TY  - JOUR
AU  - Taboun, Abdulrraouf
AU  - Jovanović, Marija
AU  - Petrović, Miloš
AU  - Stajčić, Ivana
AU  - Pešić, Ivan
AU  - Stojanović, Dušica B.
AU  - Radojević, Vesna
PY  - 2024
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/7455
AB  - The aim of this study is to investigate the influence of cross-linking and reinforcements in gelatin on the physico-mechanical properties of obtained composites. The gelatin-based composites cross-linked with citric acid (CA) were prepared: gelatin type B (GB) and β-tricalcium phosphate (β-TCP) and novel hybrid composite GB with β-TCP and hydroxyapatite (HAp) particles, and their structure, thermal, and mechanical properties were compared with pure gelatin B samples. FTIR analysis revealed that no chemical interaction between the reinforcements and gelatin matrix was established during the processing of hybrid composites by the solution casting method, proving the particles had no influence on GB cross-linking. The morphological investigation of hybrid composites revealed that cross-linking with CA improved the dispersion of particles, which further led to an increase in mechanical performance. The microindentation test showed that the hardness value was increased by up to 449%, which shows the high potential of β-TCP and HAp particle reinforcement combined with CA as a cross-linking agent. Furthermore, the reduced modulus of elasticity was increased by up to 288%. Results of the MTT assay on L929 cells have revealed that the hybrid composite GB-TCP-HA-CA was not cytotoxic. These results showed that GB cross-linked with CA and reinforced with different calcium phosphates presents a valuable novel material with potential applications in dentistry.
PB  - MDPI
T2  - Polymers
T1  - Citric Acid Cross-Linked Gelatin-Based Composites with Improved Microhardness
IS  - 8
SP  - 1077
VL  - 16
DO  - 10.3390/polym16081077
ER  - 

@article{
author = "Taboun, Abdulrraouf and Jovanović, Marija and Petrović, Miloš and Stajčić, Ivana and Pešić, Ivan and Stojanović, Dušica B. and Radojević, Vesna",
year = "2024",
abstract = "The aim of this study is to investigate the influence of cross-linking and reinforcements in gelatin on the physico-mechanical properties of obtained composites. The gelatin-based composites cross-linked with citric acid (CA) were prepared: gelatin type B (GB) and β-tricalcium phosphate (β-TCP) and novel hybrid composite GB with β-TCP and hydroxyapatite (HAp) particles, and their structure, thermal, and mechanical properties were compared with pure gelatin B samples. FTIR analysis revealed that no chemical interaction between the reinforcements and gelatin matrix was established during the processing of hybrid composites by the solution casting method, proving the particles had no influence on GB cross-linking. The morphological investigation of hybrid composites revealed that cross-linking with CA improved the dispersion of particles, which further led to an increase in mechanical performance. The microindentation test showed that the hardness value was increased by up to 449%, which shows the high potential of β-TCP and HAp particle reinforcement combined with CA as a cross-linking agent. Furthermore, the reduced modulus of elasticity was increased by up to 288%. Results of the MTT assay on L929 cells have revealed that the hybrid composite GB-TCP-HA-CA was not cytotoxic. These results showed that GB cross-linked with CA and reinforced with different calcium phosphates presents a valuable novel material with potential applications in dentistry.",
publisher = "MDPI",
journal = "Polymers",
title = "Citric Acid Cross-Linked Gelatin-Based Composites with Improved Microhardness",
number = "8",
pages = "1077",
volume = "16",
doi = "10.3390/polym16081077"
}

Taboun, A., Jovanović, M., Petrović, M., Stajčić, I., Pešić, I., Stojanović, D. B.,& Radojević, V.. (2024). Citric Acid Cross-Linked Gelatin-Based Composites with Improved Microhardness. in Polymers
MDPI., 16(8), 1077.
https://doi.org/10.3390/polym16081077

Taboun A, Jovanović M, Petrović M, Stajčić I, Pešić I, Stojanović DB, Radojević V. Citric Acid Cross-Linked Gelatin-Based Composites with Improved Microhardness. in Polymers. 2024;16(8):1077.
doi:10.3390/polym16081077 .

Taboun, Abdulrraouf, Jovanović, Marija, Petrović, Miloš, Stajčić, Ivana, Pešić, Ivan, Stojanović, Dušica B., Radojević, Vesna, "Citric Acid Cross-Linked Gelatin-Based Composites with Improved Microhardness" in Polymers, 16, no. 8 (2024):1077,
https://doi.org/10.3390/polym16081077 . .

TY  - JOUR
AU  - Elhmali, Houda Taher
AU  - Stajčić, Ivana
AU  - Stajčić, Aleksandar
AU  - Pešić, Ivan
AU  - Jovanović, Marija
AU  - Petrović, Miloš
AU  - Radojević, Vesna
PY  - 2024
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/7157
AB  - While dental poly methyl methacrylate(PMMA) possesses distinctive qualities such as ease of fabrication, cost-effectiveness, and favorable physical and mechanical properties, these attributes alone are inadequate to impart the necessary impact strength and hardness. Consequently, pure PMMA is less suitable for dental applications. This research focused on the incorporation of Strontium titanate (SrTiO3-STO) and hybrid filler STO/Manganese oxide (MnO2) to improve impact resistance and hardness. The potential of STO in reinforcing PMMA is poorly investigated, while hybrid filler STO/MnO2 has not been presented yet. Differential scanning calorimetry is conducted in order to investigate the agglomeration influence on the PMMA glass transition temperature (Tg), as well as the leaching of residual monomer and volatile additives that could pose a threat to human health. It has been determined that agglomeration with 1 wt% loading had no influence on Tg, while the first scan revealed differences in evaporation of small molecules, in favor of composite PMMA-STO/MnO2, which showed the trapping potential of volatiles. Investigations of mechanical properties have revealed the significant influence of hybrid STO/MnO2 filler on microhardness and total absorbed impact energy, which were increased by 89.9% and 145.4%, respectively. Results presented in this study revealed the reinforcing potential of hybrid nanoparticles that could find application in other polymers as well.
PB  - MDPI
T2  - Polymers
T1  - Influence of Novel SrTiO3/MnO2 Hybrid Nanoparticles on Poly(methyl methacrylate) Thermal and Mechanical Behavior
IS  - 2
SP  - 278
VL  - 16
DO  - 10.3390/polym16020278
ER  - 

@article{
author = "Elhmali, Houda Taher and Stajčić, Ivana and Stajčić, Aleksandar and Pešić, Ivan and Jovanović, Marija and Petrović, Miloš and Radojević, Vesna",
year = "2024",
abstract = "While dental poly methyl methacrylate(PMMA) possesses distinctive qualities such as ease of fabrication, cost-effectiveness, and favorable physical and mechanical properties, these attributes alone are inadequate to impart the necessary impact strength and hardness. Consequently, pure PMMA is less suitable for dental applications. This research focused on the incorporation of Strontium titanate (SrTiO3-STO) and hybrid filler STO/Manganese oxide (MnO2) to improve impact resistance and hardness. The potential of STO in reinforcing PMMA is poorly investigated, while hybrid filler STO/MnO2 has not been presented yet. Differential scanning calorimetry is conducted in order to investigate the agglomeration influence on the PMMA glass transition temperature (Tg), as well as the leaching of residual monomer and volatile additives that could pose a threat to human health. It has been determined that agglomeration with 1 wt% loading had no influence on Tg, while the first scan revealed differences in evaporation of small molecules, in favor of composite PMMA-STO/MnO2, which showed the trapping potential of volatiles. Investigations of mechanical properties have revealed the significant influence of hybrid STO/MnO2 filler on microhardness and total absorbed impact energy, which were increased by 89.9% and 145.4%, respectively. Results presented in this study revealed the reinforcing potential of hybrid nanoparticles that could find application in other polymers as well.",
publisher = "MDPI",
journal = "Polymers",
title = "Influence of Novel SrTiO3/MnO2 Hybrid Nanoparticles on Poly(methyl methacrylate) Thermal and Mechanical Behavior",
number = "2",
pages = "278",
volume = "16",
doi = "10.3390/polym16020278"
}

Elhmali, H. T., Stajčić, I., Stajčić, A., Pešić, I., Jovanović, M., Petrović, M.,& Radojević, V.. (2024). Influence of Novel SrTiO3/MnO2 Hybrid Nanoparticles on Poly(methyl methacrylate) Thermal and Mechanical Behavior. in Polymers
MDPI., 16(2), 278.
https://doi.org/10.3390/polym16020278

Elhmali HT, Stajčić I, Stajčić A, Pešić I, Jovanović M, Petrović M, Radojević V. Influence of Novel SrTiO3/MnO2 Hybrid Nanoparticles on Poly(methyl methacrylate) Thermal and Mechanical Behavior. in Polymers. 2024;16(2):278.
doi:10.3390/polym16020278 .

Elhmali, Houda Taher, Stajčić, Ivana, Stajčić, Aleksandar, Pešić, Ivan, Jovanović, Marija, Petrović, Miloš, Radojević, Vesna, "Influence of Novel SrTiO3/MnO2 Hybrid Nanoparticles on Poly(methyl methacrylate) Thermal and Mechanical Behavior" in Polymers, 16, no. 2 (2024):278,
https://doi.org/10.3390/polym16020278 . .

TY  - JOUR
AU  - Embirsh, Hifa Salah Adeen
AU  - Stajčić, Ivana
AU  - Gržetić, Jelena
AU  - Mladenović, Ivana O.
AU  - Anđelković, Boban
AU  - Marinković, Aleksandar
AU  - Vuksanović, Marija M.
PY  - 2023
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/6610
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/6663
AB  - This paper presents sustainable technology for environmentally friendly composite production. Biobased unsaturated polyester resin (b-UPR), synthesized from waste polyethylene terephthalate (PET) glycosylate and renewable origin maleic anhydride (MAnh) and propylene glycol(PG), was reinforced with unmodified and vinyl-modified biosilica nanoparticles obtained fromrice husk. The structural and morphological properties of the obtained particles, b-UPR, as well ascomposites, were characterized by Fourier-transform infrared spectroscopy (FTIR), nuclear magneticresonance spectroscopy (NMR), scanning electron microscopy (SEM), and transmission electronmicroscopy (TEM) techniques. The study of the influence of biosilica modification on the mechanicalproperties of composites was supported by hardness modeling. Improvement of the tensile strengthof the b-UPR-based composite at 2.5 wt.% addition of biosilica modified with vinyl silane, named“b-UPR/SiO2-V” composite, has been achieved with 88% increase. The thermal aging process appliedto the b-UPR/SiO2-V composite, which simulates use over the product’s lifetime, leads to the deterioration of composites that were used as fillers in commercial unsaturated polyester resin (c-UPR).The grinded artificially aged b-UPR composites were used as filler in c-UPR for the production of atable top layer with outstanding mechanical properties, i.e., impact resistance and microhardness, aswell as fire resistance rated in the V-0 category according to the UL-94 test. Developing sustainablecomposites that are chemically synthesized from renewable sources is important from the aspect ofpreserving the environment and existing resources as well as the extending their life cycle.
PB  - MDPI
T2  - Polymers
T1  - Synthesis, Characterization and Application of Biobased Unsaturated Polyester Resin Reinforced with Unmodified/Modified Biosilica Nanoparticles
IS  - 18
SP  - 3756
VL  - 15
DO  - 10.3390/polym15183756
ER  - 

@article{
author = "Embirsh, Hifa Salah Adeen and Stajčić, Ivana and Gržetić, Jelena and Mladenović, Ivana O. and Anđelković, Boban and Marinković, Aleksandar and Vuksanović, Marija M.",
year = "2023",
abstract = "This paper presents sustainable technology for environmentally friendly composite production. Biobased unsaturated polyester resin (b-UPR), synthesized from waste polyethylene terephthalate (PET) glycosylate and renewable origin maleic anhydride (MAnh) and propylene glycol(PG), was reinforced with unmodified and vinyl-modified biosilica nanoparticles obtained fromrice husk. The structural and morphological properties of the obtained particles, b-UPR, as well ascomposites, were characterized by Fourier-transform infrared spectroscopy (FTIR), nuclear magneticresonance spectroscopy (NMR), scanning electron microscopy (SEM), and transmission electronmicroscopy (TEM) techniques. The study of the influence of biosilica modification on the mechanicalproperties of composites was supported by hardness modeling. Improvement of the tensile strengthof the b-UPR-based composite at 2.5 wt.% addition of biosilica modified with vinyl silane, named“b-UPR/SiO2-V” composite, has been achieved with 88% increase. The thermal aging process appliedto the b-UPR/SiO2-V composite, which simulates use over the product’s lifetime, leads to the deterioration of composites that were used as fillers in commercial unsaturated polyester resin (c-UPR).The grinded artificially aged b-UPR composites were used as filler in c-UPR for the production of atable top layer with outstanding mechanical properties, i.e., impact resistance and microhardness, aswell as fire resistance rated in the V-0 category according to the UL-94 test. Developing sustainablecomposites that are chemically synthesized from renewable sources is important from the aspect ofpreserving the environment and existing resources as well as the extending their life cycle.",
publisher = "MDPI",
journal = "Polymers",
title = "Synthesis, Characterization and Application of Biobased Unsaturated Polyester Resin Reinforced with Unmodified/Modified Biosilica Nanoparticles",
number = "18",
pages = "3756",
volume = "15",
doi = "10.3390/polym15183756"
}

Embirsh, H. S. A., Stajčić, I., Gržetić, J., Mladenović, I. O., Anđelković, B., Marinković, A.,& Vuksanović, M. M.. (2023). Synthesis, Characterization and Application of Biobased Unsaturated Polyester Resin Reinforced with Unmodified/Modified Biosilica Nanoparticles. in Polymers
MDPI., 15(18), 3756.
https://doi.org/10.3390/polym15183756

Embirsh HSA, Stajčić I, Gržetić J, Mladenović IO, Anđelković B, Marinković A, Vuksanović MM. Synthesis, Characterization and Application of Biobased Unsaturated Polyester Resin Reinforced with Unmodified/Modified Biosilica Nanoparticles. in Polymers. 2023;15(18):3756.
doi:10.3390/polym15183756 .

Embirsh, Hifa Salah Adeen, Stajčić, Ivana, Gržetić, Jelena, Mladenović, Ivana O., Anđelković, Boban, Marinković, Aleksandar, Vuksanović, Marija M., "Synthesis, Characterization and Application of Biobased Unsaturated Polyester Resin Reinforced with Unmodified/Modified Biosilica Nanoparticles" in Polymers, 15, no. 18 (2023):3756,
https://doi.org/10.3390/polym15183756 . .

TY  - JOUR
AU  - Stajčić, Ivana
AU  - Stajčić, Aleksandar
AU  - Serpa, Cristina
AU  - Vasiljević-Radović, Dana
AU  - Ranđelović, Branislav
AU  - Radojević, Vesna
AU  - Fecht, Hans
PY  - 2022
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5296
AB  - Polymers and polymer matrix composites are commonly used materials with applications extending from packaging materials to delicate electronic devices. Epoxy resins and fiber-reinforced epoxy-based composites have been used as adhesives and construction parts. Fractal analysis has been recognized in materials science as a valuable tool for the microstructural characterization of composites by connecting fractal characteristics with composites’ functional properties. In this study, fractal reconstructions of different microstructural shapes in an epoxy-based composite were performed on field emission scanning electron microscopy (FESEM) images. These images were of glass fiber reinforced epoxy as well as a hybrid composite containing both glass and electrospun polystyrene fibers in an epoxy matrix. Fractal reconstruction enables the identification of self-similarity in the fractal structure, which represents a novelty in analyzing the fractal properties of materials. Fractal Real Finder software, based on the mathematical affine fractal regression model, was employed to reconstruct different microstructure shapes and calculate fractal dimensions to develop a method of predicting the optimal structure–property relations in composite materials in the future.
PB  - MDPI
T2  - Fractal and Fractional
T1  - Microstructure of Epoxy-Based Composites: Fractal Nature Analysis †
IS  - 12
SP  - 741
VL  - 6
DO  - 10.3390/fractalfract6120741
ER  - 

@article{
author = "Stajčić, Ivana and Stajčić, Aleksandar and Serpa, Cristina and Vasiljević-Radović, Dana and Ranđelović, Branislav and Radojević, Vesna and Fecht, Hans",
year = "2022",
abstract = "Polymers and polymer matrix composites are commonly used materials with applications extending from packaging materials to delicate electronic devices. Epoxy resins and fiber-reinforced epoxy-based composites have been used as adhesives and construction parts. Fractal analysis has been recognized in materials science as a valuable tool for the microstructural characterization of composites by connecting fractal characteristics with composites’ functional properties. In this study, fractal reconstructions of different microstructural shapes in an epoxy-based composite were performed on field emission scanning electron microscopy (FESEM) images. These images were of glass fiber reinforced epoxy as well as a hybrid composite containing both glass and electrospun polystyrene fibers in an epoxy matrix. Fractal reconstruction enables the identification of self-similarity in the fractal structure, which represents a novelty in analyzing the fractal properties of materials. Fractal Real Finder software, based on the mathematical affine fractal regression model, was employed to reconstruct different microstructure shapes and calculate fractal dimensions to develop a method of predicting the optimal structure–property relations in composite materials in the future.",
publisher = "MDPI",
journal = "Fractal and Fractional",
title = "Microstructure of Epoxy-Based Composites: Fractal Nature Analysis †",
number = "12",
pages = "741",
volume = "6",
doi = "10.3390/fractalfract6120741"
}

Stajčić, I., Stajčić, A., Serpa, C., Vasiljević-Radović, D., Ranđelović, B., Radojević, V.,& Fecht, H.. (2022). Microstructure of Epoxy-Based Composites: Fractal Nature Analysis †. in Fractal and Fractional
MDPI., 6(12), 741.
https://doi.org/10.3390/fractalfract6120741

Stajčić I, Stajčić A, Serpa C, Vasiljević-Radović D, Ranđelović B, Radojević V, Fecht H. Microstructure of Epoxy-Based Composites: Fractal Nature Analysis †. in Fractal and Fractional. 2022;6(12):741.
doi:10.3390/fractalfract6120741 .

Stajčić, Ivana, Stajčić, Aleksandar, Serpa, Cristina, Vasiljević-Radović, Dana, Ranđelović, Branislav, Radojević, Vesna, Fecht, Hans, "Microstructure of Epoxy-Based Composites: Fractal Nature Analysis †" in Fractal and Fractional, 6, no. 12 (2022):741,
https://doi.org/10.3390/fractalfract6120741 . .