TY  - JOUR
AU  - Sejkot, Petr
AU  - Aloisio, Angelo
AU  - Obradović, Vera
AU  - Iqbal, Asif
PY  - 2024
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/7447
AB  - Engineered wood products along with advanced processing and fabrication are pushing the limits of modern wood construction. Innovative concepts and applications facilitate the development of a new generation of structural systems. However, capacities of such systems are often governed by capabilities of the connections. This paper presents the experimental results with numerical and analytical models of angle brackets for prediction of load bearing capacity, stiffness, and ductility.
Three types of metal brackets in beam-column connections have been investigated and their performance has been studied in various loading arrangements. Detailed finite-element models of each connection have been developed to gain insights into their behavior. An analytical approach is also adopted to represent the connections. Comparison with test data suggests that
the models can reproduce results with good accuracy. The findings confirm feasibility of implementing ductile connections in practical mass timber structures.
PB  - Canadian Science Publishing
T2  - Canadian Journal of Civil Engineering
T1  - Experimental, finite element and analytical characterization of hysteretic response of ductile connections with nailed angle brackets for mass timber structures
DO  - 10.1139/cjce-2023-0394
ER  - 

@article{
author = "Sejkot, Petr and Aloisio, Angelo and Obradović, Vera and Iqbal, Asif",
year = "2024",
abstract = "Engineered wood products along with advanced processing and fabrication are pushing the limits of modern wood construction. Innovative concepts and applications facilitate the development of a new generation of structural systems. However, capacities of such systems are often governed by capabilities of the connections. This paper presents the experimental results with numerical and analytical models of angle brackets for prediction of load bearing capacity, stiffness, and ductility.
Three types of metal brackets in beam-column connections have been investigated and their performance has been studied in various loading arrangements. Detailed finite-element models of each connection have been developed to gain insights into their behavior. An analytical approach is also adopted to represent the connections. Comparison with test data suggests that
the models can reproduce results with good accuracy. The findings confirm feasibility of implementing ductile connections in practical mass timber structures.",
publisher = "Canadian Science Publishing",
journal = "Canadian Journal of Civil Engineering",
title = "Experimental, finite element and analytical characterization of hysteretic response of ductile connections with nailed angle brackets for mass timber structures",
doi = "10.1139/cjce-2023-0394"
}

Sejkot, P., Aloisio, A., Obradović, V.,& Iqbal, A.. (2024). Experimental, finite element and analytical characterization of hysteretic response of ductile connections with nailed angle brackets for mass timber structures. in Canadian Journal of Civil Engineering
Canadian Science Publishing..
https://doi.org/10.1139/cjce-2023-0394

Sejkot P, Aloisio A, Obradović V, Iqbal A. Experimental, finite element and analytical characterization of hysteretic response of ductile connections with nailed angle brackets for mass timber structures. in Canadian Journal of Civil Engineering. 2024;.
doi:10.1139/cjce-2023-0394 .

Sejkot, Petr, Aloisio, Angelo, Obradović, Vera, Iqbal, Asif, "Experimental, finite element and analytical characterization of hysteretic response of ductile connections with nailed angle brackets for mass timber structures" in Canadian Journal of Civil Engineering (2024),
https://doi.org/10.1139/cjce-2023-0394 . .

TY  - JOUR
AU  - Obradović, Vera
AU  - Sejkot, Petr
AU  - Zabloudil, Adam
AU  - Machalická, Klára V.
AU  - Vokáč, Miroslav
PY  - 2024
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/7320
AB  - Kevlar fibers are widely used for industrial and military purposes due to their remarkable mechanical properties, such as their high tenacity and high strength-to-weight ratio. In this study, two-layered Kevlar composite specimens were impregnated with 10 wt.% poly (vinyl butyral)/ethanol solution which contained TiO2 nanoparticles as reinforcement. The concentrations of the nanoparticles were 1 wt.% or 2 wt.% with respect to the poly (vinyl butyral), PVB. The single-axial tensile test and three-point bending test of the Kevlar/PVB composites have been performed according to the ASTM D 3039 and ASTM D 790-03 standards, respectively. The tensile and bending properties of the dry and wet Kevlar/PVB composite specimens after a 56-day immersion are examined in this work. Upon the addition of the 2 wt.% TiO2 nanoparticles, the tensile strength and modulus of the dry specimens without reinforcement were increased by 39.8% and 24.3%, respectively. All the submerged specimens’ tensile and flexural property values were lower than those of the dry specimens. After comparing the wet composite specimens to their dry counterparts, the percentage decrease in tensile strength was approximately 20%. The wet Kevlar/PVB specimens with no TiO2 reinforcement showed the greatest reduction in bending strength, 61.4% less than for the dry Kevlar/PVB specimens, due to the degradation of the PVB matrix. In addition, a numerical simulation of the three-point bending test was carried out in Abaqus.
PB  - MDPI
T2  - Buildings
T1  - Degradation Effect of Moisture on Mechanical Properties of Kevlar/PVB Composites with TiO2 Nanoparticles
IS  - 2
SP  - 409
VL  - 14
DO  - 10.3390/buildings14020409
ER  - 

@article{
author = "Obradović, Vera and Sejkot, Petr and Zabloudil, Adam and Machalická, Klára V. and Vokáč, Miroslav",
year = "2024",
abstract = "Kevlar fibers are widely used for industrial and military purposes due to their remarkable mechanical properties, such as their high tenacity and high strength-to-weight ratio. In this study, two-layered Kevlar composite specimens were impregnated with 10 wt.% poly (vinyl butyral)/ethanol solution which contained TiO2 nanoparticles as reinforcement. The concentrations of the nanoparticles were 1 wt.% or 2 wt.% with respect to the poly (vinyl butyral), PVB. The single-axial tensile test and three-point bending test of the Kevlar/PVB composites have been performed according to the ASTM D 3039 and ASTM D 790-03 standards, respectively. The tensile and bending properties of the dry and wet Kevlar/PVB composite specimens after a 56-day immersion are examined in this work. Upon the addition of the 2 wt.% TiO2 nanoparticles, the tensile strength and modulus of the dry specimens without reinforcement were increased by 39.8% and 24.3%, respectively. All the submerged specimens’ tensile and flexural property values were lower than those of the dry specimens. After comparing the wet composite specimens to their dry counterparts, the percentage decrease in tensile strength was approximately 20%. The wet Kevlar/PVB specimens with no TiO2 reinforcement showed the greatest reduction in bending strength, 61.4% less than for the dry Kevlar/PVB specimens, due to the degradation of the PVB matrix. In addition, a numerical simulation of the three-point bending test was carried out in Abaqus.",
publisher = "MDPI",
journal = "Buildings",
title = "Degradation Effect of Moisture on Mechanical Properties of Kevlar/PVB Composites with TiO2 Nanoparticles",
number = "2",
pages = "409",
volume = "14",
doi = "10.3390/buildings14020409"
}

Obradović, V., Sejkot, P., Zabloudil, A., Machalická, K. V.,& Vokáč, M.. (2024). Degradation Effect of Moisture on Mechanical Properties of Kevlar/PVB Composites with TiO2 Nanoparticles. in Buildings
MDPI., 14(2), 409.
https://doi.org/10.3390/buildings14020409

Obradović V, Sejkot P, Zabloudil A, Machalická KV, Vokáč M. Degradation Effect of Moisture on Mechanical Properties of Kevlar/PVB Composites with TiO2 Nanoparticles. in Buildings. 2024;14(2):409.
doi:10.3390/buildings14020409 .

Obradović, Vera, Sejkot, Petr, Zabloudil, Adam, Machalická, Klára V., Vokáč, Miroslav, "Degradation Effect of Moisture on Mechanical Properties of Kevlar/PVB Composites with TiO2 Nanoparticles" in Buildings, 14, no. 2 (2024):409,
https://doi.org/10.3390/buildings14020409 . .

TY  - CHAP
AU  - Obradović, Vera
AU  - Radovanović, Željko
AU  - Sejkot, Petr
AU  - Machalická, Klára V.
AU  - Vokáč, Miroslav
PY  - 2024
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/7068
AB  - The Kevlar fabric composites have a wide range of applications in the
body armor and lightweight vehicle-armor structures. Nanoparticles are one of the
most common nanofillers for these structures. In this research, the testing specimens have been made from the Kevlar fabrics impregnated with the poly (vinyl
butyral)/ethanol solution which had been reinforced with the ZnO nanoparticles.
The two-layered composite samples have been fabricated by means of hot compression. The immersion of the square Kevlar/PVB specimens for the water uptake
measurements has been performed according to the ISO 62 standard. The specimens have been immersed in a water bath filled with the distilled water (40 °C) in
the period of 8 weeks. The Kevlar/PVB specimens have been tested in accordance
with the ASTM D 3039 standard for the tensile properties and the ASTM D 790–
03 standard for the flexural properties. The tensile and bending characteristics of
the dry specimens have been compared with the ones that had undergone the water
immersion.
PB  - Springer Nature Switzerland
T2  - Modern Building Materials, Structures and Techniques
T1  - Effects of Water Immersion on Mechanical Properties of Kevlar Composites Reinforced with ZnO Nanoparticles
EP  - 277
SP  - 268
VL  - 392
DO  - 10.1007/978-3-031-44603-0_27
ER  - 

@inbook{
author = "Obradović, Vera and Radovanović, Željko and Sejkot, Petr and Machalická, Klára V. and Vokáč, Miroslav",
year = "2024",
abstract = "The Kevlar fabric composites have a wide range of applications in the
body armor and lightweight vehicle-armor structures. Nanoparticles are one of the
most common nanofillers for these structures. In this research, the testing specimens have been made from the Kevlar fabrics impregnated with the poly (vinyl
butyral)/ethanol solution which had been reinforced with the ZnO nanoparticles.
The two-layered composite samples have been fabricated by means of hot compression. The immersion of the square Kevlar/PVB specimens for the water uptake
measurements has been performed according to the ISO 62 standard. The specimens have been immersed in a water bath filled with the distilled water (40 °C) in
the period of 8 weeks. The Kevlar/PVB specimens have been tested in accordance
with the ASTM D 3039 standard for the tensile properties and the ASTM D 790–
03 standard for the flexural properties. The tensile and bending characteristics of
the dry specimens have been compared with the ones that had undergone the water
immersion.",
publisher = "Springer Nature Switzerland",
journal = "Modern Building Materials, Structures and Techniques",
booktitle = "Effects of Water Immersion on Mechanical Properties of Kevlar Composites Reinforced with ZnO Nanoparticles",
pages = "277-268",
volume = "392",
doi = "10.1007/978-3-031-44603-0_27"
}

Obradović, V., Radovanović, Ž., Sejkot, P., Machalická, K. V.,& Vokáč, M.. (2024). Effects of Water Immersion on Mechanical Properties of Kevlar Composites Reinforced with ZnO Nanoparticles. in Modern Building Materials, Structures and Techniques
Springer Nature Switzerland., 392, 268-277.
https://doi.org/10.1007/978-3-031-44603-0_27

Obradović V, Radovanović Ž, Sejkot P, Machalická KV, Vokáč M. Effects of Water Immersion on Mechanical Properties of Kevlar Composites Reinforced with ZnO Nanoparticles. in Modern Building Materials, Structures and Techniques. 2024;392:268-277.
doi:10.1007/978-3-031-44603-0_27 .

Obradović, Vera, Radovanović, Željko, Sejkot, Petr, Machalická, Klára V., Vokáč, Miroslav, "Effects of Water Immersion on Mechanical Properties of Kevlar Composites Reinforced with ZnO Nanoparticles" in Modern Building Materials, Structures and Techniques, 392 (2024):268-277,
https://doi.org/10.1007/978-3-031-44603-0_27 . .

TY  - CONF
AU  - Obradović, Vera
AU  - Sejkot, Petr
AU  - Machalická, Klára V.
AU  - Vokáč, Miroslav
PY  - 2023
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/7070
AB  - In this research, the testing specimens were made from the Kevlar fabrics impregnated with 10
wt.% poly (vinyl butyral)/ethanol solution but with the addition of the TiO2 nanoparticles. The
tensile and bending properties of the dry specimens were compared with the ones that had been
immersed in a water bath filled with distilled water (40°C) in the period of 8 weeks.
The PVB/fabric weight ratio for the impregnation of the woven Kevlar fabric was 20 wt.%. The
Kevlar/PVB fabric composites were reinforced with the TiO2 nanoparticles in different
concentrations (1 wt.% or 2 wt.% of reinforcement regarding poly (vinyl butyral), PVB). The
two layers of composite fabrics were hot-pressed by using the digital press at a temperature of
170 °C for 30 minutes.
The immersion of the square Kevlar/PVB composite specimens for the water weight gain
measurements was performed according to the ISO 62 standard. The Kevlar/PVB specimens
were tested in accordance with the ASTM D 3039 standard for the tensile properties and ASTM
D 790-03 standard for the flexural properties.
During the tensile and the flexural test, the complete fracture of the specimens did not occur.
The addition of 2 wt.% TiO2 nanoparticles produced 39.8% and 24.3% improvement in the
tensile strength and tensile modulus, respectively, compared to the dry Kevlar/PVB specimens
without reinforcement. The tensile properties of all the immersed Kevlar/PVB composite
specimens had decreased values compared to the ones of their dry specimens.
Unlike the tensile test results, the best flexural properties (strength and modulus) were achieved
with the dry specimens with no particles due to the better bonding between their two
impregnated fabric layers since the presence of TiO2 nanoparticles reduced the shear
connection between the layers. However, there was not such a decline in the properties of the
wet specimens with nanoparticles which even made some improvement in the bending strength
compared to the wet Kevlar/PVB specimens.
C3  - Scientific Program and Book of Abstracts / 9th International Conference on Fatigue of Composites (ICFC9), Vicenza, University of Padova, 21-23 June 2023
T1  - Environmental durability of Kevlar composites reinforced with TiO2 nanoparticles
SP  - 48
UR  - https://hdl.handle.net/21.15107/rcub_technorep_7070
ER  - 

@conference{
author = "Obradović, Vera and Sejkot, Petr and Machalická, Klára V. and Vokáč, Miroslav",
year = "2023",
abstract = "In this research, the testing specimens were made from the Kevlar fabrics impregnated with 10
wt.% poly (vinyl butyral)/ethanol solution but with the addition of the TiO2 nanoparticles. The
tensile and bending properties of the dry specimens were compared with the ones that had been
immersed in a water bath filled with distilled water (40°C) in the period of 8 weeks.
The PVB/fabric weight ratio for the impregnation of the woven Kevlar fabric was 20 wt.%. The
Kevlar/PVB fabric composites were reinforced with the TiO2 nanoparticles in different
concentrations (1 wt.% or 2 wt.% of reinforcement regarding poly (vinyl butyral), PVB). The
two layers of composite fabrics were hot-pressed by using the digital press at a temperature of
170 °C for 30 minutes.
The immersion of the square Kevlar/PVB composite specimens for the water weight gain
measurements was performed according to the ISO 62 standard. The Kevlar/PVB specimens
were tested in accordance with the ASTM D 3039 standard for the tensile properties and ASTM
D 790-03 standard for the flexural properties.
During the tensile and the flexural test, the complete fracture of the specimens did not occur.
The addition of 2 wt.% TiO2 nanoparticles produced 39.8% and 24.3% improvement in the
tensile strength and tensile modulus, respectively, compared to the dry Kevlar/PVB specimens
without reinforcement. The tensile properties of all the immersed Kevlar/PVB composite
specimens had decreased values compared to the ones of their dry specimens.
Unlike the tensile test results, the best flexural properties (strength and modulus) were achieved
with the dry specimens with no particles due to the better bonding between their two
impregnated fabric layers since the presence of TiO2 nanoparticles reduced the shear
connection between the layers. However, there was not such a decline in the properties of the
wet specimens with nanoparticles which even made some improvement in the bending strength
compared to the wet Kevlar/PVB specimens.",
journal = "Scientific Program and Book of Abstracts / 9th International Conference on Fatigue of Composites (ICFC9), Vicenza, University of Padova, 21-23 June 2023",
title = "Environmental durability of Kevlar composites reinforced with TiO2 nanoparticles",
pages = "48",
url = "https://hdl.handle.net/21.15107/rcub_technorep_7070"
}

Obradović, V., Sejkot, P., Machalická, K. V.,& Vokáč, M.. (2023). Environmental durability of Kevlar composites reinforced with TiO2 nanoparticles. in Scientific Program and Book of Abstracts / 9th International Conference on Fatigue of Composites (ICFC9), Vicenza, University of Padova, 21-23 June 2023, 48.
https://hdl.handle.net/21.15107/rcub_technorep_7070

Obradović V, Sejkot P, Machalická KV, Vokáč M. Environmental durability of Kevlar composites reinforced with TiO2 nanoparticles. in Scientific Program and Book of Abstracts / 9th International Conference on Fatigue of Composites (ICFC9), Vicenza, University of Padova, 21-23 June 2023. 2023;:48.
https://hdl.handle.net/21.15107/rcub_technorep_7070 .

Obradović, Vera, Sejkot, Petr, Machalická, Klára V., Vokáč, Miroslav, "Environmental durability of Kevlar composites reinforced with TiO2 nanoparticles" in Scientific Program and Book of Abstracts / 9th International Conference on Fatigue of Composites (ICFC9), Vicenza, University of Padova, 21-23 June 2023 (2023):48,
https://hdl.handle.net/21.15107/rcub_technorep_7070 .

TY  - JOUR
AU  - Obradović, Vera
AU  - Vuksanović, Marija M.
AU  - Tomić, Nataša
AU  - Petrović, Miloš
AU  - Marinković, Aleksandar
AU  - Stojanović, Dušica
AU  - Radojević, Vesna
AU  - Jančić-Heinemann, Radmila
AU  - Uskoković, Petar
PY  - 2022
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5167
AB  - This study presents the impact properties of the new form of hybrid thermoplastic composites. The Kolon fabrics were impregnated with the 10 wt% poly (vinyl butyral) (PVB)/ethanol solution with the addition of silica (SiO2) particles originating from rice husk or layered double hydroxide modified silica particles (FeAl-LDH@SiO2) as reinforcement. All the composites consisted of one layer of the impregnated fabric where the silica particles concentrations were 0.5 wt% and 1.0 wt% regarding PVB. The impact properties of the composite samples were analyzed by the controlled energy puncture impact tester. The structures of the composite samples were determined by the attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) and field emission scanning electron microscopy (FE-SEM). The results showed that the Kolon/PVB/1 wt% FeAl-LDH@SiO2 sample yielded the maximum impact force.
T2  - Materials Letters
T1  - Impact properties of Kolon/PVB fabrics reinforced with rice-husk silica particles
SP  - 132668
VL  - 324
DO  - 10.1016/j.matlet.2022.132668
ER  - 

@article{
author = "Obradović, Vera and Vuksanović, Marija M. and Tomić, Nataša and Petrović, Miloš and Marinković, Aleksandar and Stojanović, Dušica and Radojević, Vesna and Jančić-Heinemann, Radmila and Uskoković, Petar",
year = "2022",
abstract = "This study presents the impact properties of the new form of hybrid thermoplastic composites. The Kolon fabrics were impregnated with the 10 wt% poly (vinyl butyral) (PVB)/ethanol solution with the addition of silica (SiO2) particles originating from rice husk or layered double hydroxide modified silica particles (FeAl-LDH@SiO2) as reinforcement. All the composites consisted of one layer of the impregnated fabric where the silica particles concentrations were 0.5 wt% and 1.0 wt% regarding PVB. The impact properties of the composite samples were analyzed by the controlled energy puncture impact tester. The structures of the composite samples were determined by the attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) and field emission scanning electron microscopy (FE-SEM). The results showed that the Kolon/PVB/1 wt% FeAl-LDH@SiO2 sample yielded the maximum impact force.",
journal = "Materials Letters",
title = "Impact properties of Kolon/PVB fabrics reinforced with rice-husk silica particles",
pages = "132668",
volume = "324",
doi = "10.1016/j.matlet.2022.132668"
}

Obradović, V., Vuksanović, M. M., Tomić, N., Petrović, M., Marinković, A., Stojanović, D., Radojević, V., Jančić-Heinemann, R.,& Uskoković, P.. (2022). Impact properties of Kolon/PVB fabrics reinforced with rice-husk silica particles. in Materials Letters, 324, 132668.
https://doi.org/10.1016/j.matlet.2022.132668

Obradović V, Vuksanović MM, Tomić N, Petrović M, Marinković A, Stojanović D, Radojević V, Jančić-Heinemann R, Uskoković P. Impact properties of Kolon/PVB fabrics reinforced with rice-husk silica particles. in Materials Letters. 2022;324:132668.
doi:10.1016/j.matlet.2022.132668 .

Obradović, Vera, Vuksanović, Marija M., Tomić, Nataša, Petrović, Miloš, Marinković, Aleksandar, Stojanović, Dušica, Radojević, Vesna, Jančić-Heinemann, Radmila, Uskoković, Petar, "Impact properties of Kolon/PVB fabrics reinforced with rice-husk silica particles" in Materials Letters, 324 (2022):132668,
https://doi.org/10.1016/j.matlet.2022.132668 . .

Obradović, V., Vuksanović, M., Tomić, N., Petrović, M., Marinković, A., Radojević, V., Jančić Heinemann, R., Stojanović, D.,& Uskoković, P.. (2021). Primena čestica silicijum dioksida dobijenog iz biomase za ojačanje aramidnih kompozita otpornih na udar. .
https://hdl.handle.net/21.15107/rcub_technorep_7067

Obradović V, Vuksanović M, Tomić N, Petrović M, Marinković A, Radojević V, Jančić Heinemann R, Stojanović D, Uskoković P. Primena čestica silicijum dioksida dobijenog iz biomase za ojačanje aramidnih kompozita otpornih na udar. 2021;.
https://hdl.handle.net/21.15107/rcub_technorep_7067 .

Obradović, Vera, Vuksanović, Marija, Tomić, Nataša, Petrović, Miloš, Marinković, Aleksandar, Radojević, Vesna, Jančić Heinemann, Radmila, Stojanović, Dušica, Uskoković, Petar, "Primena čestica silicijum dioksida dobijenog iz biomase za ojačanje aramidnih kompozita otpornih na udar" (2021),
https://hdl.handle.net/21.15107/rcub_technorep_7067 .

TY  - CONF
AU  - Obradović, Vera
AU  - Bajić, Danica
AU  - Sejkot, Petr
AU  - Fidanovski, Bojana
AU  - Machalická, Klára V.
AU  - Vokáč, Miroslav
PY  - 2021
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/7076
AB  - The para-aramid fibres (Kevlar, Twaron, Kolon) are high performance polymeric fibres characterized by their high tenacity, strength to weight ratio and impact resistance. They are used for the soft body armour structures in ballistics and for the manufacture of parts in aerospace and automotive industry.
In this study, the specimens were made from the two-layered Kolon fabrics impregnated with epoxy resin where some silicon carbide (SiC) microparticles or SiC nanofibres were added as reinforcement. These composite specimens
were fabricated by hot compression and curing of epoxy resin.
Despite their good mechanical strength it is a well-known fact that the mechanical properties of epoxy resins are affected by moisture absorption. The tensile and impact properties of the untreated specimens were compared with the ones that underwent water absorption in the duration of 72h (immersion or humidity) followed by desorption. The immersion of the specimens in water and the exposure to high humidity (70%) were completed in accordance with the ISO 62 standard while the tensile test was performed according to the ASTM D 3039 standard. Furthermore, the tensile test simulation of the Kolon/epoxy composite by using software Abaqus® was accomplished.
For the determination of the absorbed impact energy and the impact toughness of the composite specimens, an impact test was performed by using the Charpy impact pendulum in accordance with the ASTM D5942 standard.
PB  - Royal Society of Chemistry
C3  - Book of poster Abstracts / 15th International conference on materials chemistry (MC15) - online, United Kingdom, July 12-15, 2021
T1  - Effect of moisture absorption on the mechanical properties of Kolon/ epoxy composites
SP  - P104
UR  - https://hdl.handle.net/21.15107/rcub_technorep_7076
ER  - 

@conference{
author = "Obradović, Vera and Bajić, Danica and Sejkot, Petr and Fidanovski, Bojana and Machalická, Klára V. and Vokáč, Miroslav",
year = "2021",
abstract = "The para-aramid fibres (Kevlar, Twaron, Kolon) are high performance polymeric fibres characterized by their high tenacity, strength to weight ratio and impact resistance. They are used for the soft body armour structures in ballistics and for the manufacture of parts in aerospace and automotive industry.
In this study, the specimens were made from the two-layered Kolon fabrics impregnated with epoxy resin where some silicon carbide (SiC) microparticles or SiC nanofibres were added as reinforcement. These composite specimens
were fabricated by hot compression and curing of epoxy resin.
Despite their good mechanical strength it is a well-known fact that the mechanical properties of epoxy resins are affected by moisture absorption. The tensile and impact properties of the untreated specimens were compared with the ones that underwent water absorption in the duration of 72h (immersion or humidity) followed by desorption. The immersion of the specimens in water and the exposure to high humidity (70%) were completed in accordance with the ISO 62 standard while the tensile test was performed according to the ASTM D 3039 standard. Furthermore, the tensile test simulation of the Kolon/epoxy composite by using software Abaqus® was accomplished.
For the determination of the absorbed impact energy and the impact toughness of the composite specimens, an impact test was performed by using the Charpy impact pendulum in accordance with the ASTM D5942 standard.",
publisher = "Royal Society of Chemistry",
journal = "Book of poster Abstracts / 15th International conference on materials chemistry (MC15) - online, United Kingdom, July 12-15, 2021",
title = "Effect of moisture absorption on the mechanical properties of Kolon/ epoxy composites",
pages = "P104",
url = "https://hdl.handle.net/21.15107/rcub_technorep_7076"
}

Obradović, V., Bajić, D., Sejkot, P., Fidanovski, B., Machalická, K. V.,& Vokáč, M.. (2021). Effect of moisture absorption on the mechanical properties of Kolon/ epoxy composites. in Book of poster Abstracts / 15th International conference on materials chemistry (MC15) - online, United Kingdom, July 12-15, 2021
Royal Society of Chemistry., P104.
https://hdl.handle.net/21.15107/rcub_technorep_7076

Obradović V, Bajić D, Sejkot P, Fidanovski B, Machalická KV, Vokáč M. Effect of moisture absorption on the mechanical properties of Kolon/ epoxy composites. in Book of poster Abstracts / 15th International conference on materials chemistry (MC15) - online, United Kingdom, July 12-15, 2021. 2021;:P104.
https://hdl.handle.net/21.15107/rcub_technorep_7076 .

Obradović, Vera, Bajić, Danica, Sejkot, Petr, Fidanovski, Bojana, Machalická, Klára V., Vokáč, Miroslav, "Effect of moisture absorption on the mechanical properties of Kolon/ epoxy composites" in Book of poster Abstracts / 15th International conference on materials chemistry (MC15) - online, United Kingdom, July 12-15, 2021 (2021):P104,
https://hdl.handle.net/21.15107/rcub_technorep_7076 .

TY  - JOUR
AU  - Tomić, Nataša Z.
AU  - Marinković, Aleksandar D.
AU  - Balanč, Bojana
AU  - Obradović, Vera
AU  - Pavlović, Vladimir
AU  - Manojlović, Vaso
AU  - Vuksanović, Marija M.
PY  - 2021
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/4944
AB  - Intelligent pedestrian crossings were made with the aim to increase pedestrian safety at poorly lit locations. New technologies include the design of polymer materials that have high performance by optimizing properties such as compression, tensile and impact strengths, wear resistance, hardness and transparency. The desired properties are set up to face the demands of a heavy daily traffic load and enable the functionality. Laminate material consists of the epoxy composite reinforced with silica (SiO2) derived from rice husk waste and a protective thermoplastic polyurethane layer. The top layer of the laminate material is a transparent thermoplastic polyurethane (TPU) serving as a protective layer with high wear resistance and good adhesion with epoxy composite. Silica obtained from rice husk waste was used in reinforcing of the epoxide in order to improve the mechanical properties, diffuse the light, improve the adhesion with TPU and decrease the production costs. Micro-Vickers hardness of the epoxy composite was increased by 70% with the addition of 15 wt% of SiO2. Impact energy of the epoxy composite with 15 wt% of SiO2 was increased by 272.9% after adding the TPU layer. Compressive strength of the epoxy resin is improved by 16.2% by reinforcement with 15 wt% of SiO2, while the laminate composite material showed 207% higher compressive strength than the commonly used asphalt pavement. Moreover, the addition of 15 wt% of SiO2 improved the adhesion between epoxy composite and TPU layer (11.2%). Thus, obtained laminated material made of the epoxy composite with 15 wt% of SiO2 (obtained from rice husk waste) and TPU598 showed mechanical properties and LED light transmission/diffusion appropriate for application in the intelligent pedestrian crossings.
PB  - Springer Science and Business Media Deutschland GmbH
T2  - Iranian Polymer Journal
T1  - High-performance laminate material based on polyurethane and epoxide reinforced by silica particles from rice husk used for intelligent pedestrian crossings
EP  - 330
IS  - 3
SP  - 319
VL  - 30
DO  - 10.1007/s13726-020-00894-6
ER  - 

@article{
author = "Tomić, Nataša Z. and Marinković, Aleksandar D. and Balanč, Bojana and Obradović, Vera and Pavlović, Vladimir and Manojlović, Vaso and Vuksanović, Marija M.",
year = "2021",
abstract = "Intelligent pedestrian crossings were made with the aim to increase pedestrian safety at poorly lit locations. New technologies include the design of polymer materials that have high performance by optimizing properties such as compression, tensile and impact strengths, wear resistance, hardness and transparency. The desired properties are set up to face the demands of a heavy daily traffic load and enable the functionality. Laminate material consists of the epoxy composite reinforced with silica (SiO2) derived from rice husk waste and a protective thermoplastic polyurethane layer. The top layer of the laminate material is a transparent thermoplastic polyurethane (TPU) serving as a protective layer with high wear resistance and good adhesion with epoxy composite. Silica obtained from rice husk waste was used in reinforcing of the epoxide in order to improve the mechanical properties, diffuse the light, improve the adhesion with TPU and decrease the production costs. Micro-Vickers hardness of the epoxy composite was increased by 70% with the addition of 15 wt% of SiO2. Impact energy of the epoxy composite with 15 wt% of SiO2 was increased by 272.9% after adding the TPU layer. Compressive strength of the epoxy resin is improved by 16.2% by reinforcement with 15 wt% of SiO2, while the laminate composite material showed 207% higher compressive strength than the commonly used asphalt pavement. Moreover, the addition of 15 wt% of SiO2 improved the adhesion between epoxy composite and TPU layer (11.2%). Thus, obtained laminated material made of the epoxy composite with 15 wt% of SiO2 (obtained from rice husk waste) and TPU598 showed mechanical properties and LED light transmission/diffusion appropriate for application in the intelligent pedestrian crossings.",
publisher = "Springer Science and Business Media Deutschland GmbH",
journal = "Iranian Polymer Journal",
title = "High-performance laminate material based on polyurethane and epoxide reinforced by silica particles from rice husk used for intelligent pedestrian crossings",
pages = "330-319",
number = "3",
volume = "30",
doi = "10.1007/s13726-020-00894-6"
}

Tomić, N. Z., Marinković, A. D., Balanč, B., Obradović, V., Pavlović, V., Manojlović, V.,& Vuksanović, M. M.. (2021). High-performance laminate material based on polyurethane and epoxide reinforced by silica particles from rice husk used for intelligent pedestrian crossings. in Iranian Polymer Journal
Springer Science and Business Media Deutschland GmbH., 30(3), 319-330.
https://doi.org/10.1007/s13726-020-00894-6

Tomić NZ, Marinković AD, Balanč B, Obradović V, Pavlović V, Manojlović V, Vuksanović MM. High-performance laminate material based on polyurethane and epoxide reinforced by silica particles from rice husk used for intelligent pedestrian crossings. in Iranian Polymer Journal. 2021;30(3):319-330.
doi:10.1007/s13726-020-00894-6 .

Tomić, Nataša Z., Marinković, Aleksandar D., Balanč, Bojana, Obradović, Vera, Pavlović, Vladimir, Manojlović, Vaso, Vuksanović, Marija M., "High-performance laminate material based on polyurethane and epoxide reinforced by silica particles from rice husk used for intelligent pedestrian crossings" in Iranian Polymer Journal, 30, no. 3 (2021):319-330,
https://doi.org/10.1007/s13726-020-00894-6 . .

TY  - JOUR
AU  - Obradović, Vera
PY  - 2021
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/7069
AB  - Materijali u vidu tkanina koje se proizvode
od vlakana velike žilavosti koriste se u antibalističkoj zaštiti zbog svoje male gustine, velike
otpornosti na udar i velikog kapaciteta apsorbovanja energije. Poslednjih godina para-aramidne
tkanine (lamine) imaju veliku primenu u formiranju kompozitnih struktura koje se koriste za
proizvodnju zaštitne opreme za telo. Njihova izvanredna mehanička svojstva potiču od dugačkih,
pravih poli (parafenilen tereftalamid) vlakana.
Povećanje modula skladištenja ili čvrstoće
polimera u kompozitu postiže se dodavanjem ojačanja. Različiti parametri ojačanja se uzimaju
u obzir pri njihovom odabiru za uspešnu realizaciju u kompozitu. Ugljenične nanocevi (engl.
Carbon nanotubes – CNT) predstavljaju odličan
izbor kod odabira ojačanja za polimerne kompozite zbog njihovog velikog odnosa dužina/prečnik
(koji je oko 132000000), velike čvrstoće, malih
dimenzija i mase, i velike provodljivosti.
AB  - Materials in the form of fabrics made of high
tenacity fibers are used in antiballistic protection
due to their low density, high resistance and high
energy absorption capability. In recent times, paraaramid fabrics have had a wide range of applications
in the construction of composite structures for the
production of the antiballistic body armour protection.
Their excellent mechanical properties originate
from the long, straight fibers of poly (paraphenylene
terephthalamide).
The increase of the storage modulus or the stiffness
of polymers can be achieved by adding reinforcement.
Carbon nanotubes (CNT) present a perfect choice as reinforcement in polymer composites because of
their high aspect ratio (length/diameter ratio, around
132000000), great stiffness, small size, small mass and
high conductivity.
PB  - Srpsko hemijsko društvo
T2  - Hemijski pregled
T1  - MEHANIČKA SVOJSTVA ARAMIDNIH KOMPOZITA
T1  - MECHANICAL PROPERTIES OF ARAMID COMPOSITES
EP  - 117
IS  - 3
SP  - 111
VL  - 62
UR  - https://hdl.handle.net/21.15107/rcub_technorep_7069
ER  - 

@article{
author = "Obradović, Vera",
year = "2021",
abstract = "Materijali u vidu tkanina koje se proizvode
od vlakana velike žilavosti koriste se u antibalističkoj zaštiti zbog svoje male gustine, velike
otpornosti na udar i velikog kapaciteta apsorbovanja energije. Poslednjih godina para-aramidne
tkanine (lamine) imaju veliku primenu u formiranju kompozitnih struktura koje se koriste za
proizvodnju zaštitne opreme za telo. Njihova izvanredna mehanička svojstva potiču od dugačkih,
pravih poli (parafenilen tereftalamid) vlakana.
Povećanje modula skladištenja ili čvrstoće
polimera u kompozitu postiže se dodavanjem ojačanja. Različiti parametri ojačanja se uzimaju
u obzir pri njihovom odabiru za uspešnu realizaciju u kompozitu. Ugljenične nanocevi (engl.
Carbon nanotubes – CNT) predstavljaju odličan
izbor kod odabira ojačanja za polimerne kompozite zbog njihovog velikog odnosa dužina/prečnik
(koji je oko 132000000), velike čvrstoće, malih
dimenzija i mase, i velike provodljivosti., Materials in the form of fabrics made of high
tenacity fibers are used in antiballistic protection
due to their low density, high resistance and high
energy absorption capability. In recent times, paraaramid fabrics have had a wide range of applications
in the construction of composite structures for the
production of the antiballistic body armour protection.
Their excellent mechanical properties originate
from the long, straight fibers of poly (paraphenylene
terephthalamide).
The increase of the storage modulus or the stiffness
of polymers can be achieved by adding reinforcement.
Carbon nanotubes (CNT) present a perfect choice as reinforcement in polymer composites because of
their high aspect ratio (length/diameter ratio, around
132000000), great stiffness, small size, small mass and
high conductivity.",
publisher = "Srpsko hemijsko društvo",
journal = "Hemijski pregled",
title = "MEHANIČKA SVOJSTVA ARAMIDNIH KOMPOZITA, MECHANICAL PROPERTIES OF ARAMID COMPOSITES",
pages = "117-111",
number = "3",
volume = "62",
url = "https://hdl.handle.net/21.15107/rcub_technorep_7069"
}

Obradović, V.. (2021). MEHANIČKA SVOJSTVA ARAMIDNIH KOMPOZITA. in Hemijski pregled
Srpsko hemijsko društvo., 62(3), 111-117.
https://hdl.handle.net/21.15107/rcub_technorep_7069

Obradović V. MEHANIČKA SVOJSTVA ARAMIDNIH KOMPOZITA. in Hemijski pregled. 2021;62(3):111-117.
https://hdl.handle.net/21.15107/rcub_technorep_7069 .

Obradović, Vera, "MEHANIČKA SVOJSTVA ARAMIDNIH KOMPOZITA" in Hemijski pregled, 62, no. 3 (2021):111-117,
https://hdl.handle.net/21.15107/rcub_technorep_7069 .

TY  - JOUR
AU  - Tomić, Nataša
AU  - Saleh, Mohamed Nasr
AU  - Vuksanović, Marija M.
AU  - Egelja, Adela
AU  - Obradović, Vera
AU  - Marinković, Aleksandar
AU  - Jančić-Heinemann, Radmila
PY  - 2021
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/4931
AB  - The goal of this study was to investigate the effect of the structure of Mn-Al layered double hydroxide (LDH) on the adhesion behavior of composite adhesives on two Al alloys (L3005 and L8079). The composite adhesives were made out of the UV-curing Bisphenol A glycidylmethacrylate/triethylene glycol dimethacrylate (BT) as polymer matrix and the addition of 1, 3, and 5 wt. % of Mn-Al LDH as adhesion enhancers. Adhesion was evaluated by using the micro Vickers hardness testing procedure. The wetting angle of composite adhesives to the Al substrates was measured and compared to the adhesion parameter b obtained from the microhardness tests. The highest increase in adhesion was observed for BT with 5 wt. % of Mn-Al LDH on L3005 substrate, which was more than 15 times higher than the adhesion for the neat BT. The morphological segregation of composite adhesives after the contact with Al substrates was examined by optical microscopy and a higher compatibility of Mn-Al LDH particles with L3005 substrate was found. The methods used for the adhesion properties assessment suggested that the Mn-Al LDH was the best adhesion enhancer of the BT matrix for L3005 substrate containing a higher content of Mn and surface hydroxyl groups.
T2  - Polymers
T1  - Tailored Adhesion Properties of Acrylate Adhesives on Al Alloys by the Addition of Mn-Al-LDH
IS  - 9
VL  - 13
DO  - 10.3390/polym13091525
ER  - 

@article{
author = "Tomić, Nataša and Saleh, Mohamed Nasr and Vuksanović, Marija M. and Egelja, Adela and Obradović, Vera and Marinković, Aleksandar and Jančić-Heinemann, Radmila",
year = "2021",
abstract = "The goal of this study was to investigate the effect of the structure of Mn-Al layered double hydroxide (LDH) on the adhesion behavior of composite adhesives on two Al alloys (L3005 and L8079). The composite adhesives were made out of the UV-curing Bisphenol A glycidylmethacrylate/triethylene glycol dimethacrylate (BT) as polymer matrix and the addition of 1, 3, and 5 wt. % of Mn-Al LDH as adhesion enhancers. Adhesion was evaluated by using the micro Vickers hardness testing procedure. The wetting angle of composite adhesives to the Al substrates was measured and compared to the adhesion parameter b obtained from the microhardness tests. The highest increase in adhesion was observed for BT with 5 wt. % of Mn-Al LDH on L3005 substrate, which was more than 15 times higher than the adhesion for the neat BT. The morphological segregation of composite adhesives after the contact with Al substrates was examined by optical microscopy and a higher compatibility of Mn-Al LDH particles with L3005 substrate was found. The methods used for the adhesion properties assessment suggested that the Mn-Al LDH was the best adhesion enhancer of the BT matrix for L3005 substrate containing a higher content of Mn and surface hydroxyl groups.",
journal = "Polymers",
title = "Tailored Adhesion Properties of Acrylate Adhesives on Al Alloys by the Addition of Mn-Al-LDH",
number = "9",
volume = "13",
doi = "10.3390/polym13091525"
}

Tomić, N., Saleh, M. N., Vuksanović, M. M., Egelja, A., Obradović, V., Marinković, A.,& Jančić-Heinemann, R.. (2021). Tailored Adhesion Properties of Acrylate Adhesives on Al Alloys by the Addition of Mn-Al-LDH. in Polymers, 13(9).
https://doi.org/10.3390/polym13091525

Tomić N, Saleh MN, Vuksanović MM, Egelja A, Obradović V, Marinković A, Jančić-Heinemann R. Tailored Adhesion Properties of Acrylate Adhesives on Al Alloys by the Addition of Mn-Al-LDH. in Polymers. 2021;13(9).
doi:10.3390/polym13091525 .

Tomić, Nataša, Saleh, Mohamed Nasr, Vuksanović, Marija M., Egelja, Adela, Obradović, Vera, Marinković, Aleksandar, Jančić-Heinemann, Radmila, "Tailored Adhesion Properties of Acrylate Adhesives on Al Alloys by the Addition of Mn-Al-LDH" in Polymers, 13, no. 9 (2021),
https://doi.org/10.3390/polym13091525 . .

TY  - JOUR
AU  - Obradović, Vera
AU  - Vuksanović, Marija M.
AU  - Tomić, Nataša
AU  - Stojanović, Dušica
AU  - Volkov-Husović, Tatjana
AU  - Uskoković, Petar
PY  - 2021
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/4954
AB  - In this study poly (vinyl butyral)/silica (PVB/SiO2) composite films were subjected to the cavitation process. The experiments were carried out with a 10 wt.% PVB solution in ethanol. Silica nanoparticles were added into the solution in different concentration of 1, 3 and 5 wt.% SiO2 in regard to PVB. Composite films were cast from these solutions and subjected to ultrasonic cavitation. Optical images of their surfaces were analyzed before and after cavitation, by Image-Pro Plus software. The results revealed that the PVB film with 5 wt.% SiO2 nanoparticles demonstrated the greatest improvement in microhardness with the best cavitation resistance compared to other films.
T2  - Polymers & Polymer Composites
T1  - Improvement in cavitation resistance of poly (vinyl butyral) composite films with silica nanoparticles: A technical note
EP  - S1669
IS  - 9_SUPPL
SP  - S1664
VL  - 29
DO  - 10.1177/0967391120986505
ER  - 

@article{
author = "Obradović, Vera and Vuksanović, Marija M. and Tomić, Nataša and Stojanović, Dušica and Volkov-Husović, Tatjana and Uskoković, Petar",
year = "2021",
abstract = "In this study poly (vinyl butyral)/silica (PVB/SiO2) composite films were subjected to the cavitation process. The experiments were carried out with a 10 wt.% PVB solution in ethanol. Silica nanoparticles were added into the solution in different concentration of 1, 3 and 5 wt.% SiO2 in regard to PVB. Composite films were cast from these solutions and subjected to ultrasonic cavitation. Optical images of their surfaces were analyzed before and after cavitation, by Image-Pro Plus software. The results revealed that the PVB film with 5 wt.% SiO2 nanoparticles demonstrated the greatest improvement in microhardness with the best cavitation resistance compared to other films.",
journal = "Polymers & Polymer Composites",
title = "Improvement in cavitation resistance of poly (vinyl butyral) composite films with silica nanoparticles: A technical note",
pages = "S1669-S1664",
number = "9_SUPPL",
volume = "29",
doi = "10.1177/0967391120986505"
}

Obradović, V., Vuksanović, M. M., Tomić, N., Stojanović, D., Volkov-Husović, T.,& Uskoković, P.. (2021). Improvement in cavitation resistance of poly (vinyl butyral) composite films with silica nanoparticles: A technical note. in Polymers & Polymer Composites, 29(9_SUPPL), S1664-S1669.
https://doi.org/10.1177/0967391120986505

Obradović V, Vuksanović MM, Tomić N, Stojanović D, Volkov-Husović T, Uskoković P. Improvement in cavitation resistance of poly (vinyl butyral) composite films with silica nanoparticles: A technical note. in Polymers & Polymer Composites. 2021;29(9_SUPPL):S1664-S1669.
doi:10.1177/0967391120986505 .

Obradović, Vera, Vuksanović, Marija M., Tomić, Nataša, Stojanović, Dušica, Volkov-Husović, Tatjana, Uskoković, Petar, "Improvement in cavitation resistance of poly (vinyl butyral) composite films with silica nanoparticles: A technical note" in Polymers & Polymer Composites, 29, no. 9_SUPPL (2021):S1664-S1669,
https://doi.org/10.1177/0967391120986505 . .

TY  - JOUR
AU  - Obradović, Vera
AU  - Simic, Danica
AU  - Zrilic, Milorad
AU  - Stojanović, Dušica
AU  - Uskoković, Petar
PY  - 2021
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/4968
AB  - Multilayered composites based on aramid fabrics are widely used in impact protection. The objective of this study is creating a new kind of multiaxial aramid fabric composites with inorganic fullerene-like tungsten disulfide nanoparticles (IF-WS2) and single walled carbon nanotubes (SWCNT) used as nanoreinforcement to enhance the dynamic mechanical and anti-stabbing properties of the composites. The four composites of the Kolon fabric forms were impregnated with 10 wt.% poly(vinyl butyral) (PVB)/ethanol solution which contained different forms of IF-WS nanoparticles. The surfaces of IF-WS2 were coated with silane coupling agent (m-IF) and the SWCNT were oxidized (o-SWCNT) for the fabrication of the o-SWCNT/m-IF hybrid nanoparticles. The mechanical testing showed that the Kolon/PVB/o-SWCNT/m-IF sample produced nearly 62 % of improvement in the tensile strength and 51 % of improvement in the tensile energy absorption compared to the Kolon/PVB sample. Furthermore, the sample with the o-SWCNT/m-IF hybrid nanoparticles demonstrated 24 % of enhancement in the impact toughness and 48 % of improvement in the absorbed energy after knife penetration in comparison with the Kolon/PVB sample.
T2  - Fibers and Polymers
T1  - Novel Hybrid Nanostructures of Carbon Nanotube/Fullerene-like Tungsten Disulfide as Reinforcement for Aramid Fabric Composites
EP  - 539
IS  - 2
SP  - 528
VL  - 22
DO  - 10.1007/s12221-021-0278-5
ER  - 

@article{
author = "Obradović, Vera and Simic, Danica and Zrilic, Milorad and Stojanović, Dušica and Uskoković, Petar",
year = "2021",
abstract = "Multilayered composites based on aramid fabrics are widely used in impact protection. The objective of this study is creating a new kind of multiaxial aramid fabric composites with inorganic fullerene-like tungsten disulfide nanoparticles (IF-WS2) and single walled carbon nanotubes (SWCNT) used as nanoreinforcement to enhance the dynamic mechanical and anti-stabbing properties of the composites. The four composites of the Kolon fabric forms were impregnated with 10 wt.% poly(vinyl butyral) (PVB)/ethanol solution which contained different forms of IF-WS nanoparticles. The surfaces of IF-WS2 were coated with silane coupling agent (m-IF) and the SWCNT were oxidized (o-SWCNT) for the fabrication of the o-SWCNT/m-IF hybrid nanoparticles. The mechanical testing showed that the Kolon/PVB/o-SWCNT/m-IF sample produced nearly 62 % of improvement in the tensile strength and 51 % of improvement in the tensile energy absorption compared to the Kolon/PVB sample. Furthermore, the sample with the o-SWCNT/m-IF hybrid nanoparticles demonstrated 24 % of enhancement in the impact toughness and 48 % of improvement in the absorbed energy after knife penetration in comparison with the Kolon/PVB sample.",
journal = "Fibers and Polymers",
title = "Novel Hybrid Nanostructures of Carbon Nanotube/Fullerene-like Tungsten Disulfide as Reinforcement for Aramid Fabric Composites",
pages = "539-528",
number = "2",
volume = "22",
doi = "10.1007/s12221-021-0278-5"
}

Obradović, V., Simic, D., Zrilic, M., Stojanović, D.,& Uskoković, P.. (2021). Novel Hybrid Nanostructures of Carbon Nanotube/Fullerene-like Tungsten Disulfide as Reinforcement for Aramid Fabric Composites. in Fibers and Polymers, 22(2), 528-539.
https://doi.org/10.1007/s12221-021-0278-5

Obradović V, Simic D, Zrilic M, Stojanović D, Uskoković P. Novel Hybrid Nanostructures of Carbon Nanotube/Fullerene-like Tungsten Disulfide as Reinforcement for Aramid Fabric Composites. in Fibers and Polymers. 2021;22(2):528-539.
doi:10.1007/s12221-021-0278-5 .

Obradović, Vera, Simic, Danica, Zrilic, Milorad, Stojanović, Dušica, Uskoković, Petar, "Novel Hybrid Nanostructures of Carbon Nanotube/Fullerene-like Tungsten Disulfide as Reinforcement for Aramid Fabric Composites" in Fibers and Polymers, 22, no. 2 (2021):528-539,
https://doi.org/10.1007/s12221-021-0278-5 . .

TY  - JOUR
AU  - Obradović, Vera
AU  - Simic, Danica
AU  - Sejkot, Petr
AU  - Machalicka, Klara, V
AU  - Vokac, Miroslav
PY  - 2021
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/4929
AB  - Para-aramid fibers (Kolon) are high performance polymeric fibers characterized by their high tenacity and impact resistance. They are used for the soft body armor structures in ballistics. In this study, the testing specimens were made from multilayered Kolon fabrics impregnated with epoxy resin where silicon carbide (SiC) microparticles or SiC nanofibers were added as reinforcement. The laminated composite samples were fabricated by hot compression and curing of epoxy resin. The tensile and impact strengths of the untreated specimens were compared with the ones that underwent water absorption in duration of 72 h (immersion or humidity) followed by desorption. The immersion of the specimens in water and exposure to high humidity (70%) were performed according to the ISO 62 standard while the tensile test was carried out in accordance with the ASTM D 3039 standard. In the end, the tensile test simulation of the laminated composite by using software Abaqus (R) was accomplished.
T2  - Current Applied Physics
T1  - Moisture absorption characteristics and effects on mechanical properties of Kolon/epoxy composites
EP  - 23
SP  - 16
VL  - 26
DO  - 10.1016/j.cap.2021.03.015
ER  - 

@article{
author = "Obradović, Vera and Simic, Danica and Sejkot, Petr and Machalicka, Klara, V and Vokac, Miroslav",
year = "2021",
abstract = "Para-aramid fibers (Kolon) are high performance polymeric fibers characterized by their high tenacity and impact resistance. They are used for the soft body armor structures in ballistics. In this study, the testing specimens were made from multilayered Kolon fabrics impregnated with epoxy resin where silicon carbide (SiC) microparticles or SiC nanofibers were added as reinforcement. The laminated composite samples were fabricated by hot compression and curing of epoxy resin. The tensile and impact strengths of the untreated specimens were compared with the ones that underwent water absorption in duration of 72 h (immersion or humidity) followed by desorption. The immersion of the specimens in water and exposure to high humidity (70%) were performed according to the ISO 62 standard while the tensile test was carried out in accordance with the ASTM D 3039 standard. In the end, the tensile test simulation of the laminated composite by using software Abaqus (R) was accomplished.",
journal = "Current Applied Physics",
title = "Moisture absorption characteristics and effects on mechanical properties of Kolon/epoxy composites",
pages = "23-16",
volume = "26",
doi = "10.1016/j.cap.2021.03.015"
}

Obradović, V., Simic, D., Sejkot, P., Machalicka, K. V.,& Vokac, M.. (2021). Moisture absorption characteristics and effects on mechanical properties of Kolon/epoxy composites. in Current Applied Physics, 26, 16-23.
https://doi.org/10.1016/j.cap.2021.03.015

Obradović V, Simic D, Sejkot P, Machalicka KV, Vokac M. Moisture absorption characteristics and effects on mechanical properties of Kolon/epoxy composites. in Current Applied Physics. 2021;26:16-23.
doi:10.1016/j.cap.2021.03.015 .

Obradović, Vera, Simic, Danica, Sejkot, Petr, Machalicka, Klara, V, Vokac, Miroslav, "Moisture absorption characteristics and effects on mechanical properties of Kolon/epoxy composites" in Current Applied Physics, 26 (2021):16-23,
https://doi.org/10.1016/j.cap.2021.03.015 . .

TY  - JOUR
AU  - Samolov, Aleksandra D.
AU  - Simic, Danica M.
AU  - Fidanovski, Bojana Z.
AU  - Obradović, Vera
AU  - Tomic, Ljubisa D.
AU  - Knezevic, Dragan M.
PY  - 2021
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/4824
AB  - In order to examine the possibility to improve its camouflage properties standard cotton fabric with camouflage print was impregnated with poly(vinyl butyral), PVB and fullerene-like nanoparticles of tungsten disulfide, PVB/IF-WS2. FTIR analysis excluded any possible chemical interaction of IF-WS2 with PVB and the fabric. The camouflage behavior of the impregnated fabric has been examined firstly in the VIS part of the spectrum. Diffuse reflection, specular gloss and color coordinates were measured for three different shades (black, brown and dark green). Thermal imaging was applied to examine the camouflage abilities of this impregnation in IR part of the spectrum. The obtained results show that PVB/IF-WS2 impregnation system induced enhacement of the materials camouflage properties, i.e. that IF-WS2 have a positive effect on spectrophotometric characteristics of the fabric. (c) 2020 China Ordnance Society. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).
T2  - Defence Technology
T1  - Improvement of VIS and IR camouflage properties by impregnating cotton fabric with PVB/IF-WS2
EP  - 2056
IS  - 6
SP  - 2050
VL  - 17
DO  - 10.1016/j.dt.2020.10.008
ER  - 

@article{
author = "Samolov, Aleksandra D. and Simic, Danica M. and Fidanovski, Bojana Z. and Obradović, Vera and Tomic, Ljubisa D. and Knezevic, Dragan M.",
year = "2021",
abstract = "In order to examine the possibility to improve its camouflage properties standard cotton fabric with camouflage print was impregnated with poly(vinyl butyral), PVB and fullerene-like nanoparticles of tungsten disulfide, PVB/IF-WS2. FTIR analysis excluded any possible chemical interaction of IF-WS2 with PVB and the fabric. The camouflage behavior of the impregnated fabric has been examined firstly in the VIS part of the spectrum. Diffuse reflection, specular gloss and color coordinates were measured for three different shades (black, brown and dark green). Thermal imaging was applied to examine the camouflage abilities of this impregnation in IR part of the spectrum. The obtained results show that PVB/IF-WS2 impregnation system induced enhacement of the materials camouflage properties, i.e. that IF-WS2 have a positive effect on spectrophotometric characteristics of the fabric. (c) 2020 China Ordnance Society. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).",
journal = "Defence Technology",
title = "Improvement of VIS and IR camouflage properties by impregnating cotton fabric with PVB/IF-WS2",
pages = "2056-2050",
number = "6",
volume = "17",
doi = "10.1016/j.dt.2020.10.008"
}

Samolov, A. D., Simic, D. M., Fidanovski, B. Z., Obradović, V., Tomic, L. D.,& Knezevic, D. M.. (2021). Improvement of VIS and IR camouflage properties by impregnating cotton fabric with PVB/IF-WS2. in Defence Technology, 17(6), 2050-2056.
https://doi.org/10.1016/j.dt.2020.10.008

Samolov AD, Simic DM, Fidanovski BZ, Obradović V, Tomic LD, Knezevic DM. Improvement of VIS and IR camouflage properties by impregnating cotton fabric with PVB/IF-WS2. in Defence Technology. 2021;17(6):2050-2056.
doi:10.1016/j.dt.2020.10.008 .

Samolov, Aleksandra D., Simic, Danica M., Fidanovski, Bojana Z., Obradović, Vera, Tomic, Ljubisa D., Knezevic, Dragan M., "Improvement of VIS and IR camouflage properties by impregnating cotton fabric with PVB/IF-WS2" in Defence Technology, 17, no. 6 (2021):2050-2056,
https://doi.org/10.1016/j.dt.2020.10.008 . .

TY  - JOUR
AU  - Stojanović, Dušica
AU  - Brajović, Ljiljana
AU  - Obradović, Vera
AU  - Mijailović, Daniel
AU  - Dramlić, Dragan
AU  - Kojović, Aleksandar
AU  - Uskoković, Petar
PY  - 2020
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/4454
AB  - The composite nanofibers were used as reinforcement in acrylic polymer for the overall enhancement of thermo-mechanical properties, adhesion between fibers and matrix, and fracture toughness of the final nanocomposite since acrylic materials lack of this feature. So, a good balance between hardness/toughness and transparency is obtained with the addition of poly (vinyl butyral) (PVB) and titania (TiO2) nanofibers simultaneously and controlling their contents. Specifically, when compared to that of pure acrylic polymer, the fracture toughness of the PMMA nanocomposite apparently increased 55% with the addition of 3 wt.% titania nanoparticles, while the produced nanocomposite maintained high transmittance above 75-80% in the visible domain. The transmission spectrum modelling of the reinforced fiber materials and hybrid acrylic composites using Mie scattering theory for different particle sizes and particle content is presented. The calculated transmission coefficients versus wavelength are compared with the experimental ones.
PB  - Elsevier B.V.
T2  - Progress in Organic Coatings
T1  - Hybrid acrylic nanocomposites with excellent transparency and hardness/toughness balance
SP  - 105437
VL  - 139
DO  - 10.1016/j.porgcoat.2019.105437
ER  - 

@article{
author = "Stojanović, Dušica and Brajović, Ljiljana and Obradović, Vera and Mijailović, Daniel and Dramlić, Dragan and Kojović, Aleksandar and Uskoković, Petar",
year = "2020",
abstract = "The composite nanofibers were used as reinforcement in acrylic polymer for the overall enhancement of thermo-mechanical properties, adhesion between fibers and matrix, and fracture toughness of the final nanocomposite since acrylic materials lack of this feature. So, a good balance between hardness/toughness and transparency is obtained with the addition of poly (vinyl butyral) (PVB) and titania (TiO2) nanofibers simultaneously and controlling their contents. Specifically, when compared to that of pure acrylic polymer, the fracture toughness of the PMMA nanocomposite apparently increased 55% with the addition of 3 wt.% titania nanoparticles, while the produced nanocomposite maintained high transmittance above 75-80% in the visible domain. The transmission spectrum modelling of the reinforced fiber materials and hybrid acrylic composites using Mie scattering theory for different particle sizes and particle content is presented. The calculated transmission coefficients versus wavelength are compared with the experimental ones.",
publisher = "Elsevier B.V.",
journal = "Progress in Organic Coatings",
title = "Hybrid acrylic nanocomposites with excellent transparency and hardness/toughness balance",
pages = "105437",
volume = "139",
doi = "10.1016/j.porgcoat.2019.105437"
}

Stojanović, D., Brajović, L., Obradović, V., Mijailović, D., Dramlić, D., Kojović, A.,& Uskoković, P.. (2020). Hybrid acrylic nanocomposites with excellent transparency and hardness/toughness balance. in Progress in Organic Coatings
Elsevier B.V.., 139, 105437.
https://doi.org/10.1016/j.porgcoat.2019.105437

Stojanović D, Brajović L, Obradović V, Mijailović D, Dramlić D, Kojović A, Uskoković P. Hybrid acrylic nanocomposites with excellent transparency and hardness/toughness balance. in Progress in Organic Coatings. 2020;139:105437.
doi:10.1016/j.porgcoat.2019.105437 .

Stojanović, Dušica, Brajović, Ljiljana, Obradović, Vera, Mijailović, Daniel, Dramlić, Dragan, Kojović, Aleksandar, Uskoković, Petar, "Hybrid acrylic nanocomposites with excellent transparency and hardness/toughness balance" in Progress in Organic Coatings, 139 (2020):105437,
https://doi.org/10.1016/j.porgcoat.2019.105437 . .

TY  - JOUR
AU  - Obradović, Vera
AU  - Stojanović, Dušica
AU  - Janković-Častvan, Ivona
AU  - Radojević, Vesna
AU  - Uskoković, Petar
PY  - 2018
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/3922
AB  - The aim of this study was to fabricate a new kind of hybrid fabric composites with the cross-linked electrospun poly(vinyl butyral) (PVB) composite nanofibres. The experiments were performed with the 10 wt.% PVB/ethanol solution for electrospinning where the modified silica nanoparticles (mSiO(2)), the oxidised single-walled carbon nanotubes (o-SWCNT) and the o-SWCNT/mSiO(2) hybrid nanoparticles were added to the solution. The electrospun fibres were crosslinked with glutaraldehyde (GA) afterwards in order to reinforce the composite structure by bonding to the p-aramid fabrics. The chemical and thermo-mechanical properties of the hybrid fabric composites were evaluated. The greatest improvement in thermo-mechanical properties was achieved by the sample which contained the cross-linked PVB fibres with the o-SWCNT/mSiO(2) hybrid nanoparticles.
PB  - Korean Fiber Soc, Seoul
T2  - Fibers and Polymers
T1  - Processing and Characterisation of Hybrid Aramid Fabrics Reinforced with Cross-linked Electrospun PVB Composite Nanofibres
EP  - 1929
IS  - 9
SP  - 1921
VL  - 19
DO  - 10.1007/s12221-018-8381-y
ER  - 

@article{
author = "Obradović, Vera and Stojanović, Dušica and Janković-Častvan, Ivona and Radojević, Vesna and Uskoković, Petar",
year = "2018",
abstract = "The aim of this study was to fabricate a new kind of hybrid fabric composites with the cross-linked electrospun poly(vinyl butyral) (PVB) composite nanofibres. The experiments were performed with the 10 wt.% PVB/ethanol solution for electrospinning where the modified silica nanoparticles (mSiO(2)), the oxidised single-walled carbon nanotubes (o-SWCNT) and the o-SWCNT/mSiO(2) hybrid nanoparticles were added to the solution. The electrospun fibres were crosslinked with glutaraldehyde (GA) afterwards in order to reinforce the composite structure by bonding to the p-aramid fabrics. The chemical and thermo-mechanical properties of the hybrid fabric composites were evaluated. The greatest improvement in thermo-mechanical properties was achieved by the sample which contained the cross-linked PVB fibres with the o-SWCNT/mSiO(2) hybrid nanoparticles.",
publisher = "Korean Fiber Soc, Seoul",
journal = "Fibers and Polymers",
title = "Processing and Characterisation of Hybrid Aramid Fabrics Reinforced with Cross-linked Electrospun PVB Composite Nanofibres",
pages = "1929-1921",
number = "9",
volume = "19",
doi = "10.1007/s12221-018-8381-y"
}

Obradović, V., Stojanović, D., Janković-Častvan, I., Radojević, V.,& Uskoković, P.. (2018). Processing and Characterisation of Hybrid Aramid Fabrics Reinforced with Cross-linked Electrospun PVB Composite Nanofibres. in Fibers and Polymers
Korean Fiber Soc, Seoul., 19(9), 1921-1929.
https://doi.org/10.1007/s12221-018-8381-y

Obradović V, Stojanović D, Janković-Častvan I, Radojević V, Uskoković P. Processing and Characterisation of Hybrid Aramid Fabrics Reinforced with Cross-linked Electrospun PVB Composite Nanofibres. in Fibers and Polymers. 2018;19(9):1921-1929.
doi:10.1007/s12221-018-8381-y .

Obradović, Vera, Stojanović, Dušica, Janković-Častvan, Ivona, Radojević, Vesna, Uskoković, Petar, "Processing and Characterisation of Hybrid Aramid Fabrics Reinforced with Cross-linked Electrospun PVB Composite Nanofibres" in Fibers and Polymers, 19, no. 9 (2018):1921-1929,
https://doi.org/10.1007/s12221-018-8381-y . .

TY  - JOUR
AU  - Alzarrug, Faisal Ali
AU  - Stojanović, Dušica
AU  - Obradović, Vera
AU  - Kojović, Aleksandar
AU  - Nedeljković, Jovan
AU  - Rajilić-Stojanović, Mirjana
AU  - Uskoković, Petar
PY  - 2017
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/3707
AB  - Titania nanofillers were used to reinforce nanofibers in composite mats produced by electrospinning of poly(vinyl butyral) with two different concentrations of polymers. The titania nanoparticles and titania nanotubes were added into an acetic acid/ethanol solution in different contents of 3 and 1wt%, respectively. The effect of the processing system on the morphology of the produced fibers was analyzed. The antimicrobial poly(vinyl butyral) composite fibers with titanium dioxide nanoparticles and titanium dioxide nanotubes were produced by single and multineedle electrospinning systems. This study reports fabrication of composite nanofibrous mats with significant mechanical and antimicrobial properties at a high production speed, which is promising for commercial applications (health care, photocatalysis, protective clothing, etc.). The reported result revealed an outstanding correlation between values of elastic modulus derived from nanoindentation and dynamic mechanical techniques.
PB  - Wiley, Hoboken
T2  - Polymers for Advanced Technologies
T1  - Multiscale characterization of antimicrobial poly(vinyl butyral)/titania nanofibrous composites
EP  - 914
IS  - 7
SP  - 909
VL  - 28
DO  - 10.1002/pat.3996
ER  - 

@article{
author = "Alzarrug, Faisal Ali and Stojanović, Dušica and Obradović, Vera and Kojović, Aleksandar and Nedeljković, Jovan and Rajilić-Stojanović, Mirjana and Uskoković, Petar",
year = "2017",
abstract = "Titania nanofillers were used to reinforce nanofibers in composite mats produced by electrospinning of poly(vinyl butyral) with two different concentrations of polymers. The titania nanoparticles and titania nanotubes were added into an acetic acid/ethanol solution in different contents of 3 and 1wt%, respectively. The effect of the processing system on the morphology of the produced fibers was analyzed. The antimicrobial poly(vinyl butyral) composite fibers with titanium dioxide nanoparticles and titanium dioxide nanotubes were produced by single and multineedle electrospinning systems. This study reports fabrication of composite nanofibrous mats with significant mechanical and antimicrobial properties at a high production speed, which is promising for commercial applications (health care, photocatalysis, protective clothing, etc.). The reported result revealed an outstanding correlation between values of elastic modulus derived from nanoindentation and dynamic mechanical techniques.",
publisher = "Wiley, Hoboken",
journal = "Polymers for Advanced Technologies",
title = "Multiscale characterization of antimicrobial poly(vinyl butyral)/titania nanofibrous composites",
pages = "914-909",
number = "7",
volume = "28",
doi = "10.1002/pat.3996"
}

Alzarrug, F. A., Stojanović, D., Obradović, V., Kojović, A., Nedeljković, J., Rajilić-Stojanović, M.,& Uskoković, P.. (2017). Multiscale characterization of antimicrobial poly(vinyl butyral)/titania nanofibrous composites. in Polymers for Advanced Technologies
Wiley, Hoboken., 28(7), 909-914.
https://doi.org/10.1002/pat.3996

Alzarrug FA, Stojanović D, Obradović V, Kojović A, Nedeljković J, Rajilić-Stojanović M, Uskoković P. Multiscale characterization of antimicrobial poly(vinyl butyral)/titania nanofibrous composites. in Polymers for Advanced Technologies. 2017;28(7):909-914.
doi:10.1002/pat.3996 .

Alzarrug, Faisal Ali, Stojanović, Dušica, Obradović, Vera, Kojović, Aleksandar, Nedeljković, Jovan, Rajilić-Stojanović, Mirjana, Uskoković, Petar, "Multiscale characterization of antimicrobial poly(vinyl butyral)/titania nanofibrous composites" in Polymers for Advanced Technologies, 28, no. 7 (2017):909-914,
https://doi.org/10.1002/pat.3996 . .

TY  - JOUR
AU  - Obradović, Vera
AU  - Stojanović, Dušica
AU  - Jokić, Bojan
AU  - Zrilić, Milorad
AU  - Radojević, Vesna
AU  - Uskoković, Petar
AU  - Aleksić, Radoslav
PY  - 2017
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/3662
AB  - In this study carbon nanotubes (CNT) and silica nanoparticles (SiO2) were added to enhance the dynamic mechanical and anti-stabbing properties of the polyurethaneip-aramid multiaxial fabric (Kolon fabric) composites for ballistic protection. The SiO2 were modified (mSiO(2)) and CNT were oxidised (o-CNT) in order to fabricate o-CNT/mSiO(2) hybrid nanoparticles. Various kinds of nanoreinforcement particles were added into poly (vinyl butyral) (PVB)/ethanol solution. The results revealed that the films PVB/oMWCNT/mSiO(2) and PVB/o-SWCNT/mSiO(2) yielded 101% and 141% improvement in indentation hardness together with 89% and 117% improvement in reduced elastic modulus, respectively, compared to the neat PVB film. The experiments demonstrated that the Kolon/PVB/o-SWCNT/mSiO(2) fabric sample yielded 35% improvement in absorbed energy and 50% improvement in the storage modulus compared to the Kolon/PVB sample.
PB  - Elsevier Sci Ltd, Oxford
T2  - Composites Part B-Engineering
T1  - Nanomechanical and anti-stabbing properties of Kolon fabric composites reinforced with hybrid nanoparticles
EP  - 152
SP  - 143
VL  - 108
DO  - 10.1016/j.compositesb.2016.09.095
ER  - 

@article{
author = "Obradović, Vera and Stojanović, Dušica and Jokić, Bojan and Zrilić, Milorad and Radojević, Vesna and Uskoković, Petar and Aleksić, Radoslav",
year = "2017",
abstract = "In this study carbon nanotubes (CNT) and silica nanoparticles (SiO2) were added to enhance the dynamic mechanical and anti-stabbing properties of the polyurethaneip-aramid multiaxial fabric (Kolon fabric) composites for ballistic protection. The SiO2 were modified (mSiO(2)) and CNT were oxidised (o-CNT) in order to fabricate o-CNT/mSiO(2) hybrid nanoparticles. Various kinds of nanoreinforcement particles were added into poly (vinyl butyral) (PVB)/ethanol solution. The results revealed that the films PVB/oMWCNT/mSiO(2) and PVB/o-SWCNT/mSiO(2) yielded 101% and 141% improvement in indentation hardness together with 89% and 117% improvement in reduced elastic modulus, respectively, compared to the neat PVB film. The experiments demonstrated that the Kolon/PVB/o-SWCNT/mSiO(2) fabric sample yielded 35% improvement in absorbed energy and 50% improvement in the storage modulus compared to the Kolon/PVB sample.",
publisher = "Elsevier Sci Ltd, Oxford",
journal = "Composites Part B-Engineering",
title = "Nanomechanical and anti-stabbing properties of Kolon fabric composites reinforced with hybrid nanoparticles",
pages = "152-143",
volume = "108",
doi = "10.1016/j.compositesb.2016.09.095"
}

Obradović, V., Stojanović, D., Jokić, B., Zrilić, M., Radojević, V., Uskoković, P.,& Aleksić, R.. (2017). Nanomechanical and anti-stabbing properties of Kolon fabric composites reinforced with hybrid nanoparticles. in Composites Part B-Engineering
Elsevier Sci Ltd, Oxford., 108, 143-152.
https://doi.org/10.1016/j.compositesb.2016.09.095

Obradović V, Stojanović D, Jokić B, Zrilić M, Radojević V, Uskoković P, Aleksić R. Nanomechanical and anti-stabbing properties of Kolon fabric composites reinforced with hybrid nanoparticles. in Composites Part B-Engineering. 2017;108:143-152.
doi:10.1016/j.compositesb.2016.09.095 .

Obradović, Vera, Stojanović, Dušica, Jokić, Bojan, Zrilić, Milorad, Radojević, Vesna, Uskoković, Petar, Aleksić, Radoslav, "Nanomechanical and anti-stabbing properties of Kolon fabric composites reinforced with hybrid nanoparticles" in Composites Part B-Engineering, 108 (2017):143-152,
https://doi.org/10.1016/j.compositesb.2016.09.095 . .

TY  - THES
AU  - Obradović, Vera
PY  - 2016
UR  - http://eteze.bg.ac.rs/application/showtheses?thesesId=3632
UR  - https://fedorabg.bg.ac.rs/fedora/get/o:12411/bdef:Content/download
UR  - http://vbs.rs/scripts/cobiss?command=DISPLAY&base=70036&RID=48012815
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/4631
AB  - Material in the form of fabrics made of high tenacity fibers are used in antiballistic protection due to their low density, high resistance and high energy absorption capability. In recent times, p-aramid fabrics have had a wide range of applications in the construction of composite structures for the production of the antiballistic body armour protection. Their excellent mechanical properties originate from the long, straight fibers of poly(paraphenylene terephthalamide). The increase of the storage modulus or the stiffness of polymers can be achieved by adding reinforcement. Various parameters of reinforcement are taken into consideration for their selection and their prosperous realisation in composite. Ceramics have usually been used as reinforcement in the body armour owing to its properties, such as introducing flexibility and light weight of the overall protective structure. Ceramics nanosilica is one of the primary reinforcement used in polymer composites. The silica (SiO2) nanoparticles are defined by their high specific surface area. Due to their mutual agglomeration, silane coupling agents modify nanosilica surface for their successful dispersion and deagglomeration, causing the formation of chemical bonds between them and organic components. Carbon nanotubes (CNT) present a perfect choice as reinforcement in polymer composites because of their high aspect ratio (length/diameter ratio, around 132000000), great stiffness, small size and mass, and high conductivity. The surface of the p-aramid multiaxial fabric samples (Twaron and Kolon fabrics) was modified by γ-aminopropyl triethoxysilane (AMEO silane)/ethanol solution. Afterwards, the samples were impregnated with poly(vinyl butyral) (PVB)/ethanol solution with different types and contents of nanoreinforcement due to the improvement of their mechanical, thermal and ballistic properties and the increase of absorbed impact energy, which presented the aim of the research of this doctoral
AB  - Materijal u vidu tkanina koje se proizvode od vlakana velike žilavosti se koristi u antibalističkoj zaštiti zbog svoje male gustine, velike otpornosti i velikog kapaciteta apsorpcije. Poslednjih godina p-aramidne tkanine (lamine) imaju veliku primenu u formiranju različitih kompozitnih struktura koje se koriste za proizvodnju antibalističke zaštitne opreme za telo. Njihove izvanredne mehaničke osobine potiču od dugačkih, pravih poli(parafenilen tereftalamid) vlakana. Povećanje modula ili čvrstoće polimera se postiže dodavanjem ojačanja. Različiti parametri ojačanja se uzimaju u obzir pri njihovom odabiru za uspešnu realizaciju u kompozitu. U njih se ubrajaju: veličina ojačanja (čestica), njihova geometrija, orijentacija, čvrstoća i jačina veze ojačanjematrica. Keramika se, zbog svojih svojstava, često koristi za ojačavanje zaštitne opreme za telo. Time se postiže fleksibilnost i mala težina cele zaštitne strukture. U okviru keramike nanosilika predstavlja jedno od vodećih ojačanja koje se koristi u polimernim kompozitima. Silika (SiO2) nanočestice karakterišu njihova velika specifična površina. Kako dolazi do uzajamne aglomeracije nanočestica, agensi u vidu silana se koriste za modifikaciju površine nanosilike zbog njihove uspešne disperzije i deaglomeracije, uzrokujući formiranje hemijskih veza između njih i organskih komponenata. Ugljenične nanocevi (Carbon nanotubes - CNT) predstavljaju odličan izbor kod odabira ojačanja za polimerne kompozite zbog njihovog velikog odnosa dužina/prečnik (oko 132000000), velike čvrstoće, malih dimenzija i mase, i velike provodljivosti. Površina uzoraka p-aramidnih multiaksijalnih lamina (Twaron i Kolon lamina) je bila modifikovana sa γ-aminopropiltrietoksisilanom (AMEO silan)/etanol rastvorom. Uzorci su potom bili impregnisani sa poli(vinil butiral)(PVB)/etanol rastvorom sa različitim vrstom i sadržajem nanoojačanja radi poboljšanja njihovih mehaničkih, termičkih i balističkih svojstava i povećanja apsorbovane energije udara, što je predstavljalo cilj istraživanja ove doktorske teze.
PB  - Univerzitet u Beogradu, Tehnološko-metalurški fakultet
T1  - Processing and characterisation of hybrid nanocomposite materials with increased impact resistance
T1  - Procesiranje i karakterizacija hibridnih nanokompozitnih materijala povećane otpornosti na udar
UR  - https://hdl.handle.net/21.15107/rcub_technorep_4631
ER  - 

@phdthesis{
author = "Obradović, Vera",
year = "2016",
abstract = "Material in the form of fabrics made of high tenacity fibers are used in antiballistic protection due to their low density, high resistance and high energy absorption capability. In recent times, p-aramid fabrics have had a wide range of applications in the construction of composite structures for the production of the antiballistic body armour protection. Their excellent mechanical properties originate from the long, straight fibers of poly(paraphenylene terephthalamide). The increase of the storage modulus or the stiffness of polymers can be achieved by adding reinforcement. Various parameters of reinforcement are taken into consideration for their selection and their prosperous realisation in composite. Ceramics have usually been used as reinforcement in the body armour owing to its properties, such as introducing flexibility and light weight of the overall protective structure. Ceramics nanosilica is one of the primary reinforcement used in polymer composites. The silica (SiO2) nanoparticles are defined by their high specific surface area. Due to their mutual agglomeration, silane coupling agents modify nanosilica surface for their successful dispersion and deagglomeration, causing the formation of chemical bonds between them and organic components. Carbon nanotubes (CNT) present a perfect choice as reinforcement in polymer composites because of their high aspect ratio (length/diameter ratio, around 132000000), great stiffness, small size and mass, and high conductivity. The surface of the p-aramid multiaxial fabric samples (Twaron and Kolon fabrics) was modified by γ-aminopropyl triethoxysilane (AMEO silane)/ethanol solution. Afterwards, the samples were impregnated with poly(vinyl butyral) (PVB)/ethanol solution with different types and contents of nanoreinforcement due to the improvement of their mechanical, thermal and ballistic properties and the increase of absorbed impact energy, which presented the aim of the research of this doctoral, Materijal u vidu tkanina koje se proizvode od vlakana velike žilavosti se koristi u antibalističkoj zaštiti zbog svoje male gustine, velike otpornosti i velikog kapaciteta apsorpcije. Poslednjih godina p-aramidne tkanine (lamine) imaju veliku primenu u formiranju različitih kompozitnih struktura koje se koriste za proizvodnju antibalističke zaštitne opreme za telo. Njihove izvanredne mehaničke osobine potiču od dugačkih, pravih poli(parafenilen tereftalamid) vlakana. Povećanje modula ili čvrstoće polimera se postiže dodavanjem ojačanja. Različiti parametri ojačanja se uzimaju u obzir pri njihovom odabiru za uspešnu realizaciju u kompozitu. U njih se ubrajaju: veličina ojačanja (čestica), njihova geometrija, orijentacija, čvrstoća i jačina veze ojačanjematrica. Keramika se, zbog svojih svojstava, često koristi za ojačavanje zaštitne opreme za telo. Time se postiže fleksibilnost i mala težina cele zaštitne strukture. U okviru keramike nanosilika predstavlja jedno od vodećih ojačanja koje se koristi u polimernim kompozitima. Silika (SiO2) nanočestice karakterišu njihova velika specifična površina. Kako dolazi do uzajamne aglomeracije nanočestica, agensi u vidu silana se koriste za modifikaciju površine nanosilike zbog njihove uspešne disperzije i deaglomeracije, uzrokujući formiranje hemijskih veza između njih i organskih komponenata. Ugljenične nanocevi (Carbon nanotubes - CNT) predstavljaju odličan izbor kod odabira ojačanja za polimerne kompozite zbog njihovog velikog odnosa dužina/prečnik (oko 132000000), velike čvrstoće, malih dimenzija i mase, i velike provodljivosti. Površina uzoraka p-aramidnih multiaksijalnih lamina (Twaron i Kolon lamina) je bila modifikovana sa γ-aminopropiltrietoksisilanom (AMEO silan)/etanol rastvorom. Uzorci su potom bili impregnisani sa poli(vinil butiral)(PVB)/etanol rastvorom sa različitim vrstom i sadržajem nanoojačanja radi poboljšanja njihovih mehaničkih, termičkih i balističkih svojstava i povećanja apsorbovane energije udara, što je predstavljalo cilj istraživanja ove doktorske teze.",
publisher = "Univerzitet u Beogradu, Tehnološko-metalurški fakultet",
title = "Processing and characterisation of hybrid nanocomposite materials with increased impact resistance, Procesiranje i karakterizacija hibridnih nanokompozitnih materijala povećane otpornosti na udar",
url = "https://hdl.handle.net/21.15107/rcub_technorep_4631"
}

Obradović, V.. (2016). Processing and characterisation of hybrid nanocomposite materials with increased impact resistance. 
Univerzitet u Beogradu, Tehnološko-metalurški fakultet..
https://hdl.handle.net/21.15107/rcub_technorep_4631

Obradović V. Processing and characterisation of hybrid nanocomposite materials with increased impact resistance. 2016;.
https://hdl.handle.net/21.15107/rcub_technorep_4631 .

Obradović, Vera, "Processing and characterisation of hybrid nanocomposite materials with increased impact resistance" (2016),
https://hdl.handle.net/21.15107/rcub_technorep_4631 .

TY  - JOUR
AU  - Obradović, Vera
AU  - Stojanović, Dušica
AU  - Radojević, Vesna
AU  - Uskoković, Petar
AU  - Aleksić, Radoslav
PY  - 2015
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/2904
AB  - The physical and mechanical properties of the six samples of polyurethane/p-aramid multiaxial fabric forms (Kolon fabrics) were analyzed by high speed impact tester. The samples were impregnated with 10 wt.% poly (vinyl butyral) (PVB)/ethanol solution and modified with γ-aminopropyltriethoxysilane (AMEO silane)/ethanol solution. Unmodified silica (SiO2) nanoparticles, tungsten disulfide (WS2) nanoparticles and multiwalled carbon nanotubes (MWCNT) were used as reinforcement for multiaxial Kolon fabrics. The SiO2/PVB mass fraction was 10 wt.%, while the WS2/PVB and MWCNT/PVB mass fractions were the same - 1 wt.%. The results revealed the increase of the maximal impact force and the total energy absorbed for all the samples compared to the unmodified Kolon fabric sample and the application possibilities of these materials for the antiballistic protection.
AB  - Fizička i mehanička svojstva šest uzoraka poliuretan/p-aramidnih multiaksijalnih tkanina (Kolon lamina) su analizirana pomoću impakt tester uređaja. Uzorci su impregnisani sa 10 mas.% rastvorom poli (vinil butiral)(PVB)/etanol i modifikovani 2 mas.% rastvorom γ-aminopropiltrietoksisilana (AMEO silan) u etanolu. Nemodifikovane silika (SiO2) nanočestice, volfram disulfid (WS2) nanočestice i višeslojne ugljenične nanocevi (MWCNT) su korišćene kao ojačanja multiaksijalnih Kolon lamina. Maseni udeo ojačanja SiO2/PVB je bio 10 mas.%, dok su maseni udeli WS2/PVB i MWCNT/PVB bili 1 mas.%. Rezultati pokazuju povećanje maksimalne udarne sile i ukupne apsorbovane energije kod svih uzoraka u odnosu na nemodifikovani Kolon uzorak i mogućnosti primene ovih materijala za antibalističku zaštitu.
PB  - Savez inženjera i tehničara Srbije, Beograd
T2  - Tehnika
T1  - Impact testing with controlled energy of multiaxial aramid fabrics with various types of reinforcement
T1  - Ispitivanje udarima kontrolisane energije multiaksijalnih aramidnih lamina sa različitim tipovima ojačanja
EP  - 589
IS  - 4
SP  - 585
VL  - 70
DO  - 10.5937/tehnika1504585O
ER  - 

@article{
author = "Obradović, Vera and Stojanović, Dušica and Radojević, Vesna and Uskoković, Petar and Aleksić, Radoslav",
year = "2015",
abstract = "The physical and mechanical properties of the six samples of polyurethane/p-aramid multiaxial fabric forms (Kolon fabrics) were analyzed by high speed impact tester. The samples were impregnated with 10 wt.% poly (vinyl butyral) (PVB)/ethanol solution and modified with γ-aminopropyltriethoxysilane (AMEO silane)/ethanol solution. Unmodified silica (SiO2) nanoparticles, tungsten disulfide (WS2) nanoparticles and multiwalled carbon nanotubes (MWCNT) were used as reinforcement for multiaxial Kolon fabrics. The SiO2/PVB mass fraction was 10 wt.%, while the WS2/PVB and MWCNT/PVB mass fractions were the same - 1 wt.%. The results revealed the increase of the maximal impact force and the total energy absorbed for all the samples compared to the unmodified Kolon fabric sample and the application possibilities of these materials for the antiballistic protection., Fizička i mehanička svojstva šest uzoraka poliuretan/p-aramidnih multiaksijalnih tkanina (Kolon lamina) su analizirana pomoću impakt tester uređaja. Uzorci su impregnisani sa 10 mas.% rastvorom poli (vinil butiral)(PVB)/etanol i modifikovani 2 mas.% rastvorom γ-aminopropiltrietoksisilana (AMEO silan) u etanolu. Nemodifikovane silika (SiO2) nanočestice, volfram disulfid (WS2) nanočestice i višeslojne ugljenične nanocevi (MWCNT) su korišćene kao ojačanja multiaksijalnih Kolon lamina. Maseni udeo ojačanja SiO2/PVB je bio 10 mas.%, dok su maseni udeli WS2/PVB i MWCNT/PVB bili 1 mas.%. Rezultati pokazuju povećanje maksimalne udarne sile i ukupne apsorbovane energije kod svih uzoraka u odnosu na nemodifikovani Kolon uzorak i mogućnosti primene ovih materijala za antibalističku zaštitu.",
publisher = "Savez inženjera i tehničara Srbije, Beograd",
journal = "Tehnika",
title = "Impact testing with controlled energy of multiaxial aramid fabrics with various types of reinforcement, Ispitivanje udarima kontrolisane energije multiaksijalnih aramidnih lamina sa različitim tipovima ojačanja",
pages = "589-585",
number = "4",
volume = "70",
doi = "10.5937/tehnika1504585O"
}

Obradović, V., Stojanović, D., Radojević, V., Uskoković, P.,& Aleksić, R.. (2015). Impact testing with controlled energy of multiaxial aramid fabrics with various types of reinforcement. in Tehnika
Savez inženjera i tehničara Srbije, Beograd., 70(4), 585-589.
https://doi.org/10.5937/tehnika1504585O

Obradović V, Stojanović D, Radojević V, Uskoković P, Aleksić R. Impact testing with controlled energy of multiaxial aramid fabrics with various types of reinforcement. in Tehnika. 2015;70(4):585-589.
doi:10.5937/tehnika1504585O .

Obradović, Vera, Stojanović, Dušica, Radojević, Vesna, Uskoković, Petar, Aleksić, Radoslav, "Impact testing with controlled energy of multiaxial aramid fabrics with various types of reinforcement" in Tehnika, 70, no. 4 (2015):585-589,
https://doi.org/10.5937/tehnika1504585O . .

TY  - JOUR
AU  - Obradović, Vera
AU  - Stojanović, Dušica
AU  - Živković, Irena
AU  - Radojević, Vesna
AU  - Uskoković, Petar
AU  - Aleksić, Radoslav
PY  - 2015
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/3038
AB  - This study presents dynamic mechanical and impact properties of the new form of hybrid thermoplastic composites. The six composites of polyurethane/p-aramid multiaxial fabric forms (Kolon fabrics) were impregnated with 10 wt% poly(vinyl. butyral) (PVB)/ethanol solution with the addition of pristine multiwalled carbon nanotubes (MWCNT) where the PVB/fabric ratio was 20 wt%. All the composites consisted of four layers of the impregnated fabrics. The MWCNT/PVB content was 0, 0.5 and 1 wt%. The surface of the three composites with different MWCNT/PVB content was modified with gamma-aminopropyltriethoxy silane (AMEO silane)/ethanol solution.. The physical and dynamic mechanical properties of the prepared composite samples were analyzed by dynamic mechanical analysis (DMA) and high speed puncture impact tester. The structures of the composite samples were investigated by scanning electron microscopy (SEM). The results showed that the Kolon/AMEO/PVB/1 wt% MWCNT sample yielded a 60 % improvement in the storage modulus and a 73 % improvement in the impact absorbed energy compared to the Kolon/PVB sample. The carbon nanotubes (MWCNT) were added to improve the dynamic mechanical and impact properties of the materials for ballistic protection.
PB  - Korean Fiber Soc, Seoul
T2  - Fibers and Polymers
T1  - Dynamic Mechanical and Impact Properties of Composites Reinforced with Carbon Nanotubes
EP  - 145
IS  - 1
SP  - 138
VL  - 16
DO  - 10.1007/s12221-015-0138-2
ER  - 

@article{
author = "Obradović, Vera and Stojanović, Dušica and Živković, Irena and Radojević, Vesna and Uskoković, Petar and Aleksić, Radoslav",
year = "2015",
abstract = "This study presents dynamic mechanical and impact properties of the new form of hybrid thermoplastic composites. The six composites of polyurethane/p-aramid multiaxial fabric forms (Kolon fabrics) were impregnated with 10 wt% poly(vinyl. butyral) (PVB)/ethanol solution with the addition of pristine multiwalled carbon nanotubes (MWCNT) where the PVB/fabric ratio was 20 wt%. All the composites consisted of four layers of the impregnated fabrics. The MWCNT/PVB content was 0, 0.5 and 1 wt%. The surface of the three composites with different MWCNT/PVB content was modified with gamma-aminopropyltriethoxy silane (AMEO silane)/ethanol solution.. The physical and dynamic mechanical properties of the prepared composite samples were analyzed by dynamic mechanical analysis (DMA) and high speed puncture impact tester. The structures of the composite samples were investigated by scanning electron microscopy (SEM). The results showed that the Kolon/AMEO/PVB/1 wt% MWCNT sample yielded a 60 % improvement in the storage modulus and a 73 % improvement in the impact absorbed energy compared to the Kolon/PVB sample. The carbon nanotubes (MWCNT) were added to improve the dynamic mechanical and impact properties of the materials for ballistic protection.",
publisher = "Korean Fiber Soc, Seoul",
journal = "Fibers and Polymers",
title = "Dynamic Mechanical and Impact Properties of Composites Reinforced with Carbon Nanotubes",
pages = "145-138",
number = "1",
volume = "16",
doi = "10.1007/s12221-015-0138-2"
}

Obradović, V., Stojanović, D., Živković, I., Radojević, V., Uskoković, P.,& Aleksić, R.. (2015). Dynamic Mechanical and Impact Properties of Composites Reinforced with Carbon Nanotubes. in Fibers and Polymers
Korean Fiber Soc, Seoul., 16(1), 138-145.
https://doi.org/10.1007/s12221-015-0138-2

Obradović V, Stojanović D, Živković I, Radojević V, Uskoković P, Aleksić R. Dynamic Mechanical and Impact Properties of Composites Reinforced with Carbon Nanotubes. in Fibers and Polymers. 2015;16(1):138-145.
doi:10.1007/s12221-015-0138-2 .

Obradović, Vera, Stojanović, Dušica, Živković, Irena, Radojević, Vesna, Uskoković, Petar, Aleksić, Radoslav, "Dynamic Mechanical and Impact Properties of Composites Reinforced with Carbon Nanotubes" in Fibers and Polymers, 16, no. 1 (2015):138-145,
https://doi.org/10.1007/s12221-015-0138-2 . .

TY  - JOUR
AU  - Obradović, Vera
AU  - Stojanović, Dušica
AU  - Jančić-Heinemann, Radmila
AU  - Zivković, Irena
AU  - Radojević, Vesna
AU  - Uskoković, Petar
AU  - Aleksić, Radoslav
PY  - 2014
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/2705
AB  - Multi-axial aramid fabrics have a wide range of applications in the construction of composite structures for body armor. Nanoparticles, which include nanosilica, are one of the most common nanofillers for these structures. The particles of nanosilica possess nanometer dimensions with high specific surface area. Silane coupling agents are mostly used for modifying nanosilica surface in order to prevent silica agglomeration. Incorporation of nanosilica treated with silane adhesion promoter, in the matrix part of the hybrid composite form, leads to increased resistance to the bullet shock impact. In this study, the resistance to penetration of a shot bullet was tested for four samples of the aramid fabric composite forms. All fabrics were coated with gamma-aminopropyl triethoxysilane (AMEO silane)/ethanol solution. Two samples were impregnated with poly (vinyl butyral) (PVB)/ethanol solution, while the other two were impregnated with the same solution, but with the addition of the 30 wt.% AMEO silane modified silica nanoparticles as reinforcement. The samples were both hard and flexible options. The bullet-shooting test was applied to all the composites by two different bullet types. The structural design of the samples improved the ballistic resistance after the bullets were shot. Some ballistic image analyses for print and penetration depth of the samples were performed using Image Pro-Plus software.
PB  - Inda, Cary
T2  - Journal of Engineered Fibers and Fabrics
T1  - Ballistic Properties of Hybrid Thermoplastic Composites with Silica Nanoparticles
EP  - 107
IS  - 4
SP  - 97
VL  - 9
UR  - https://hdl.handle.net/21.15107/rcub_technorep_2705
ER  - 

@article{
author = "Obradović, Vera and Stojanović, Dušica and Jančić-Heinemann, Radmila and Zivković, Irena and Radojević, Vesna and Uskoković, Petar and Aleksić, Radoslav",
year = "2014",
abstract = "Multi-axial aramid fabrics have a wide range of applications in the construction of composite structures for body armor. Nanoparticles, which include nanosilica, are one of the most common nanofillers for these structures. The particles of nanosilica possess nanometer dimensions with high specific surface area. Silane coupling agents are mostly used for modifying nanosilica surface in order to prevent silica agglomeration. Incorporation of nanosilica treated with silane adhesion promoter, in the matrix part of the hybrid composite form, leads to increased resistance to the bullet shock impact. In this study, the resistance to penetration of a shot bullet was tested for four samples of the aramid fabric composite forms. All fabrics were coated with gamma-aminopropyl triethoxysilane (AMEO silane)/ethanol solution. Two samples were impregnated with poly (vinyl butyral) (PVB)/ethanol solution, while the other two were impregnated with the same solution, but with the addition of the 30 wt.% AMEO silane modified silica nanoparticles as reinforcement. The samples were both hard and flexible options. The bullet-shooting test was applied to all the composites by two different bullet types. The structural design of the samples improved the ballistic resistance after the bullets were shot. Some ballistic image analyses for print and penetration depth of the samples were performed using Image Pro-Plus software.",
publisher = "Inda, Cary",
journal = "Journal of Engineered Fibers and Fabrics",
title = "Ballistic Properties of Hybrid Thermoplastic Composites with Silica Nanoparticles",
pages = "107-97",
number = "4",
volume = "9",
url = "https://hdl.handle.net/21.15107/rcub_technorep_2705"
}

Obradović, V., Stojanović, D., Jančić-Heinemann, R., Zivković, I., Radojević, V., Uskoković, P.,& Aleksić, R.. (2014). Ballistic Properties of Hybrid Thermoplastic Composites with Silica Nanoparticles. in Journal of Engineered Fibers and Fabrics
Inda, Cary., 9(4), 97-107.
https://hdl.handle.net/21.15107/rcub_technorep_2705

Obradović V, Stojanović D, Jančić-Heinemann R, Zivković I, Radojević V, Uskoković P, Aleksić R. Ballistic Properties of Hybrid Thermoplastic Composites with Silica Nanoparticles. in Journal of Engineered Fibers and Fabrics. 2014;9(4):97-107.
https://hdl.handle.net/21.15107/rcub_technorep_2705 .

Obradović, Vera, Stojanović, Dušica, Jančić-Heinemann, Radmila, Zivković, Irena, Radojević, Vesna, Uskoković, Petar, Aleksić, Radoslav, "Ballistic Properties of Hybrid Thermoplastic Composites with Silica Nanoparticles" in Journal of Engineered Fibers and Fabrics, 9, no. 4 (2014):97-107,
https://hdl.handle.net/21.15107/rcub_technorep_2705 .

TY  - JOUR
AU  - Obradović, Vera
AU  - Stojanović, Dušica
AU  - Kojović, Aleksandar
AU  - Živković, Irena
AU  - Radojević, Vesna
AU  - Uskoković, Petar
AU  - Aleksić, Radoslav
PY  - 2014
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/2603
AB  - In this study, the electrospun nanofibers, nanoparticles and nanotubes were used as reinforcement in order to improve mechanical properties of materials for ballistic protection. The samples of polyurethane/p-aramid multiaxial fabric forms (Twaron fabrics and Colon fabrics) were impregnated with poly (vinyl butyral) (PVB) ethanol solution with the different content of reinforcement. Due to the improvement in mechanical, ballistic and impact properties, the surface modification of the fabrics with γ-aminopropyltriethoxysilane (AMEO silane)/ethanol solution was used and silica nanoparticles were modified with AMEO silane. This study is divided into three parts of research: electrospinning process, ballistic testing of the p-aramid composites and impact tester analysis of the Colon composites. The mechanical properties of all the composites were tested by the dynamic mechanical analysis (DMA).
AB  - U ovom istraživanju su se elektrospinovana vlakna, nanočestice i nanocevi koristili kao ojačanja koja bi unapredila mehanička svojstva materijala za balističku zaštitu. Uzorci poliuretan/paramidnih multiaksijalnih lamina (Twaron i Kolon lamine) su impregnisani sa poli(vinil butiral)(PVB)/etanol rastvorom sa različitim sadržajem ojačanja. Radi poboljšanja mehaničkih, balističkih i impakt svojstava, modifikovala se površina lamina sa γ-aminopropiltrietoksisilanom (AMEO silan)/etanol rastvorom i koristile su se silika nanočestice modifikovane AMEO silanom. Ovaj rad je podeljen na tri dela istraživanja: proces elektrospininga, balističko testiranje paramidnih kompozita i impakt tester analiza Kolon kompozita. Mehanička svojstva svih kompozita su bila testirana pomoću dinamičko mehaničke analize (DMA).
PB  - Engineering Society for Corrosion, Belgrade, Serbia
T2  - Zaštita materijala
T1  - Aramid composites impregnated with different reinforcement: Nanofibers, nanoparticles and nanotubes
T1  - Aramidni kompoziti impregnisani sa različitim ojačanjima - nanovlakna, nanočestice i nanocevi
EP  - 361
IS  - 4
SP  - 351
VL  - 55
DO  - 10.5937/ZasMat1404351O
ER  - 

@article{
author = "Obradović, Vera and Stojanović, Dušica and Kojović, Aleksandar and Živković, Irena and Radojević, Vesna and Uskoković, Petar and Aleksić, Radoslav",
year = "2014",
abstract = "In this study, the electrospun nanofibers, nanoparticles and nanotubes were used as reinforcement in order to improve mechanical properties of materials for ballistic protection. The samples of polyurethane/p-aramid multiaxial fabric forms (Twaron fabrics and Colon fabrics) were impregnated with poly (vinyl butyral) (PVB) ethanol solution with the different content of reinforcement. Due to the improvement in mechanical, ballistic and impact properties, the surface modification of the fabrics with γ-aminopropyltriethoxysilane (AMEO silane)/ethanol solution was used and silica nanoparticles were modified with AMEO silane. This study is divided into three parts of research: electrospinning process, ballistic testing of the p-aramid composites and impact tester analysis of the Colon composites. The mechanical properties of all the composites were tested by the dynamic mechanical analysis (DMA)., U ovom istraživanju su se elektrospinovana vlakna, nanočestice i nanocevi koristili kao ojačanja koja bi unapredila mehanička svojstva materijala za balističku zaštitu. Uzorci poliuretan/paramidnih multiaksijalnih lamina (Twaron i Kolon lamine) su impregnisani sa poli(vinil butiral)(PVB)/etanol rastvorom sa različitim sadržajem ojačanja. Radi poboljšanja mehaničkih, balističkih i impakt svojstava, modifikovala se površina lamina sa γ-aminopropiltrietoksisilanom (AMEO silan)/etanol rastvorom i koristile su se silika nanočestice modifikovane AMEO silanom. Ovaj rad je podeljen na tri dela istraživanja: proces elektrospininga, balističko testiranje paramidnih kompozita i impakt tester analiza Kolon kompozita. Mehanička svojstva svih kompozita su bila testirana pomoću dinamičko mehaničke analize (DMA).",
publisher = "Engineering Society for Corrosion, Belgrade, Serbia",
journal = "Zaštita materijala",
title = "Aramid composites impregnated with different reinforcement: Nanofibers, nanoparticles and nanotubes, Aramidni kompoziti impregnisani sa različitim ojačanjima - nanovlakna, nanočestice i nanocevi",
pages = "361-351",
number = "4",
volume = "55",
doi = "10.5937/ZasMat1404351O"
}

Obradović, V., Stojanović, D., Kojović, A., Živković, I., Radojević, V., Uskoković, P.,& Aleksić, R.. (2014). Aramid composites impregnated with different reinforcement: Nanofibers, nanoparticles and nanotubes. in Zaštita materijala
Engineering Society for Corrosion, Belgrade, Serbia., 55(4), 351-361.
https://doi.org/10.5937/ZasMat1404351O

Obradović V, Stojanović D, Kojović A, Živković I, Radojević V, Uskoković P, Aleksić R. Aramid composites impregnated with different reinforcement: Nanofibers, nanoparticles and nanotubes. in Zaštita materijala. 2014;55(4):351-361.
doi:10.5937/ZasMat1404351O .

Obradović, Vera, Stojanović, Dušica, Kojović, Aleksandar, Živković, Irena, Radojević, Vesna, Uskoković, Petar, Aleksić, Radoslav, "Aramid composites impregnated with different reinforcement: Nanofibers, nanoparticles and nanotubes" in Zaštita materijala, 55, no. 4 (2014):351-361,
https://doi.org/10.5937/ZasMat1404351O . .

TY  - JOUR
AU  - Obradović, Vera
AU  - Stojanović, Dušica
AU  - Kojović, Aleksandar
AU  - Zivković, Irena
AU  - Radojević, Vesna
AU  - Uskoković, Petar
AU  - Aleksić, Radoslav
PY  - 2014
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/2554
AB  - The poly (vinyl butyral)/silica (PVB/SiO2) composite fibers were produced by the electrospinning process. The experiments were performed with the PVB solution in concentration of 10 wt.% where ethanol was used as the solvent. The silica nanoparticles were added into the solution in different content of 1, 3 and 5 wt.% SiO2. The PVB fibers with 50 wt.% SiO2 nanoparticles were deposited on p-aramid fabrics which were coated with PVB solution. The effect of the processing parameters on the morphology of PVB/SiO2 composite fibers was analysed. Mechanical properties of the p-aramid fabrics were tested by dynamic mechanical analysis (DMA).
T2  - Materiale Plastice
T1  - Electrospun Poly(vinylbutyral)/silica Composite Fibres for Impregnation of Aramid Fabrics
EP  - 322
IS  - 3
SP  - 319
VL  - 51
UR  - https://hdl.handle.net/21.15107/rcub_technorep_2554
ER  - 

@article{
author = "Obradović, Vera and Stojanović, Dušica and Kojović, Aleksandar and Zivković, Irena and Radojević, Vesna and Uskoković, Petar and Aleksić, Radoslav",
year = "2014",
abstract = "The poly (vinyl butyral)/silica (PVB/SiO2) composite fibers were produced by the electrospinning process. The experiments were performed with the PVB solution in concentration of 10 wt.% where ethanol was used as the solvent. The silica nanoparticles were added into the solution in different content of 1, 3 and 5 wt.% SiO2. The PVB fibers with 50 wt.% SiO2 nanoparticles were deposited on p-aramid fabrics which were coated with PVB solution. The effect of the processing parameters on the morphology of PVB/SiO2 composite fibers was analysed. Mechanical properties of the p-aramid fabrics were tested by dynamic mechanical analysis (DMA).",
journal = "Materiale Plastice",
title = "Electrospun Poly(vinylbutyral)/silica Composite Fibres for Impregnation of Aramid Fabrics",
pages = "322-319",
number = "3",
volume = "51",
url = "https://hdl.handle.net/21.15107/rcub_technorep_2554"
}

Obradović, V., Stojanović, D., Kojović, A., Zivković, I., Radojević, V., Uskoković, P.,& Aleksić, R.. (2014). Electrospun Poly(vinylbutyral)/silica Composite Fibres for Impregnation of Aramid Fabrics. in Materiale Plastice, 51(3), 319-322.
https://hdl.handle.net/21.15107/rcub_technorep_2554

Obradović V, Stojanović D, Kojović A, Zivković I, Radojević V, Uskoković P, Aleksić R. Electrospun Poly(vinylbutyral)/silica Composite Fibres for Impregnation of Aramid Fabrics. in Materiale Plastice. 2014;51(3):319-322.
https://hdl.handle.net/21.15107/rcub_technorep_2554 .

Obradović, Vera, Stojanović, Dušica, Kojović, Aleksandar, Zivković, Irena, Radojević, Vesna, Uskoković, Petar, Aleksić, Radoslav, "Electrospun Poly(vinylbutyral)/silica Composite Fibres for Impregnation of Aramid Fabrics" in Materiale Plastice, 51, no. 3 (2014):319-322,
https://hdl.handle.net/21.15107/rcub_technorep_2554 .

TY  - JOUR
AU  - Obradović, Vera
AU  - Stojanović, D.
AU  - Grković, Mirjana
AU  - Živković, Irena
AU  - Radojević, Vesna
AU  - Uskoković, Petar
AU  - Aleksić, Radoslav
PY  - 2013
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/2324
AB  - In this study six samples of polyurethane/p-aramid multiaxial fabric forms (Colon fabrics) were coated with 10 wt.% poly (vinyl butyral) (PVB)/ethanol solution with the addition of multiwalled carbon nanotubes (MWCNT). The solution was impregnated on both sides of each of the fabrics. All composite samples consisted of four layers of the impregnated fabrics. The MWCNT/PVB content was 0, 0.1 and 1 wt.%. The three samples of the fabrics with different MWCNT/PVB content were coated with y-aminopropyltriethoxysilane (AMEO silane)/ethanol solution due to the surface modification. The mechanical properties of the prepared composite samples were studied by dynamic mechanical analysis (DMA). The 60% increase in storage modulus was achieved by addition of MWCNT and impregnation of aramid fabrics with AMEO silane. The pristine multiwalled carbon nanotubes (MWCNT) were introduced in order to enhance additionally the mechanical properties of the materials for ballistic protection.
PB  - Association of Metallurgical Engineers of Serbia
T2  - Metallurgical & Materials Engineering
T1  - Dynamic mechanical properties of aramid fabrics impregnated with carbon nanotube/poly (vinyl butyral)/ethanol solution
EP  - 266
IS  - 3
SP  - 259
VL  - 19
UR  - https://hdl.handle.net/21.15107/rcub_technorep_2324
ER  - 

@article{
author = "Obradović, Vera and Stojanović, D. and Grković, Mirjana and Živković, Irena and Radojević, Vesna and Uskoković, Petar and Aleksić, Radoslav",
year = "2013",
abstract = "In this study six samples of polyurethane/p-aramid multiaxial fabric forms (Colon fabrics) were coated with 10 wt.% poly (vinyl butyral) (PVB)/ethanol solution with the addition of multiwalled carbon nanotubes (MWCNT). The solution was impregnated on both sides of each of the fabrics. All composite samples consisted of four layers of the impregnated fabrics. The MWCNT/PVB content was 0, 0.1 and 1 wt.%. The three samples of the fabrics with different MWCNT/PVB content were coated with y-aminopropyltriethoxysilane (AMEO silane)/ethanol solution due to the surface modification. The mechanical properties of the prepared composite samples were studied by dynamic mechanical analysis (DMA). The 60% increase in storage modulus was achieved by addition of MWCNT and impregnation of aramid fabrics with AMEO silane. The pristine multiwalled carbon nanotubes (MWCNT) were introduced in order to enhance additionally the mechanical properties of the materials for ballistic protection.",
publisher = "Association of Metallurgical Engineers of Serbia",
journal = "Metallurgical & Materials Engineering",
title = "Dynamic mechanical properties of aramid fabrics impregnated with carbon nanotube/poly (vinyl butyral)/ethanol solution",
pages = "266-259",
number = "3",
volume = "19",
url = "https://hdl.handle.net/21.15107/rcub_technorep_2324"
}

Obradović, V., Stojanović, D., Grković, M., Živković, I., Radojević, V., Uskoković, P.,& Aleksić, R.. (2013). Dynamic mechanical properties of aramid fabrics impregnated with carbon nanotube/poly (vinyl butyral)/ethanol solution. in Metallurgical & Materials Engineering
Association of Metallurgical Engineers of Serbia., 19(3), 259-266.
https://hdl.handle.net/21.15107/rcub_technorep_2324

Obradović V, Stojanović D, Grković M, Živković I, Radojević V, Uskoković P, Aleksić R. Dynamic mechanical properties of aramid fabrics impregnated with carbon nanotube/poly (vinyl butyral)/ethanol solution. in Metallurgical & Materials Engineering. 2013;19(3):259-266.
https://hdl.handle.net/21.15107/rcub_technorep_2324 .

Obradović, Vera, Stojanović, D., Grković, Mirjana, Živković, Irena, Radojević, Vesna, Uskoković, Petar, Aleksić, Radoslav, "Dynamic mechanical properties of aramid fabrics impregnated with carbon nanotube/poly (vinyl butyral)/ethanol solution" in Metallurgical & Materials Engineering, 19, no. 3 (2013):259-266,
https://hdl.handle.net/21.15107/rcub_technorep_2324 .