TY  - JOUR
AU  - Grković, Mirjana
AU  - Stojanović, Dušica
AU  - Kojović, Aleksandar
AU  - Strnad, Simona
AU  - Kreže, Tatjana
AU  - Aleksić, Radoslav
AU  - Uskoković, Petar
PY  - 2015
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/3068
AB  - Polyethylene oxide (PEO) functionalized graphene (f-G) was prepared by ultrasonication of pristine graphene in PEO aqueous solution. The feasible sonication protocol of PEO degradation and graphene functionalization enabled fabrication of solvent cast nanocomposites. Additionally, the steps to form new bio-nanocomposite films have been described. Taking the advantage of the combination of graphene, PEO and keratin fibers from poultry feather waste, the aforementioned bio-nanocomposite films were designed with extraordinary properties allowing the films to have promising applications as eventual packaging materials and enabling bio-waste keratin to be converted into value-added materials. Compared to neat PEO, addition of only 0.3 wt% f-G provided an increase of 92% to the storage modulus. These findings are similar to the nanoindentation results, which yielded increases in the reduced modulus of the same composition by about 92%. Nanoindentation testing shows that the incorporation of 0.3 wt% f-G increased the reduced modulus and hardness of the keratin-PEO blend by about 155 and 99%, respectively.
PB  - Royal Society of Chemistry
T2  - RSC Advances
T1  - Keratin-polyethylene oxide bio-nanocomposites reinforced with ultrasonically functionalized graphene
EP  - 91287
IS  - 111
SP  - 91280
VL  - 5
DO  - 10.1039/c5ra12402f
ER  - 

@article{
author = "Grković, Mirjana and Stojanović, Dušica and Kojović, Aleksandar and Strnad, Simona and Kreže, Tatjana and Aleksić, Radoslav and Uskoković, Petar",
year = "2015",
abstract = "Polyethylene oxide (PEO) functionalized graphene (f-G) was prepared by ultrasonication of pristine graphene in PEO aqueous solution. The feasible sonication protocol of PEO degradation and graphene functionalization enabled fabrication of solvent cast nanocomposites. Additionally, the steps to form new bio-nanocomposite films have been described. Taking the advantage of the combination of graphene, PEO and keratin fibers from poultry feather waste, the aforementioned bio-nanocomposite films were designed with extraordinary properties allowing the films to have promising applications as eventual packaging materials and enabling bio-waste keratin to be converted into value-added materials. Compared to neat PEO, addition of only 0.3 wt% f-G provided an increase of 92% to the storage modulus. These findings are similar to the nanoindentation results, which yielded increases in the reduced modulus of the same composition by about 92%. Nanoindentation testing shows that the incorporation of 0.3 wt% f-G increased the reduced modulus and hardness of the keratin-PEO blend by about 155 and 99%, respectively.",
publisher = "Royal Society of Chemistry",
journal = "RSC Advances",
title = "Keratin-polyethylene oxide bio-nanocomposites reinforced with ultrasonically functionalized graphene",
pages = "91287-91280",
number = "111",
volume = "5",
doi = "10.1039/c5ra12402f"
}

Grković, M., Stojanović, D., Kojović, A., Strnad, S., Kreže, T., Aleksić, R.,& Uskoković, P.. (2015). Keratin-polyethylene oxide bio-nanocomposites reinforced with ultrasonically functionalized graphene. in RSC Advances
Royal Society of Chemistry., 5(111), 91280-91287.
https://doi.org/10.1039/c5ra12402f

Grković M, Stojanović D, Kojović A, Strnad S, Kreže T, Aleksić R, Uskoković P. Keratin-polyethylene oxide bio-nanocomposites reinforced with ultrasonically functionalized graphene. in RSC Advances. 2015;5(111):91280-91287.
doi:10.1039/c5ra12402f .

Grković, Mirjana, Stojanović, Dušica, Kojović, Aleksandar, Strnad, Simona, Kreže, Tatjana, Aleksić, Radoslav, Uskoković, Petar, "Keratin-polyethylene oxide bio-nanocomposites reinforced with ultrasonically functionalized graphene" in RSC Advances, 5, no. 111 (2015):91280-91287,
https://doi.org/10.1039/c5ra12402f . .

TY  - JOUR
AU  - Đokić, Jelena D.
AU  - Kojović, Aleksandar
AU  - Stojanović, Dušica
AU  - Marinković, Aleksandar
AU  - Vuković, Goran D.
AU  - Aleksić, Radoslav
AU  - Uskoković, Petar
PY  - 2012
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/2077
AB  - Chitosan-based films have found increasing implementation in a variety of fields, among which are as drug delivery carriers, in the packaging industry and as water purification filters. Therefore, in order to achieve mechanical integrity of such films while preserving processability and biocompatibility, chitosan-based films are fabricated in the forms of blends with poly(ethylene oxide) (PEO). A nano-indentation study was undertaken in order to investigate the nanomechanical properties and surface morphology of chitosan films in blends with various content of PEO. The results of differential scanning calorimetry, water uptake and nano-indentation revealed that films with an 80/20 blend ratio of chitosan/PEO showed the optimal values of reduced modulus and hardness. It appears that the incorporation of the synthetic PEO in chitosan films could lower the manufacturing costs while preserving the mechanical integrity of the films.
AB  - Filmovi na bazi hitozana nalaze sve širu primenu u raznim oblastima između ostalog kao nosači lekova, u industriji ambalaže i kao filteri za prečišćavanje voda. Da bi se postigao mehanički integritet ovakvih filmova i zadržala procesabilnost i biokompatibilnost, filmovi na bazi hitozana pripremljeni su u formi blendi sa polietilen oksidom (PEO). Studija nanoindentacije urađena je u cilju proučavanja nanomehaničkih svojstava i površinske morfologije hitozanskih filmova u blendama sa različitim sadržajem PEO. Rezultati DSC-a, apsorpcije vode i nanoindentacije pokazali su da filmovi blendi sa odnosom 80/20 hitozana i PEO poseduju optimalne vrednosti redukovanog modula elastičnosti i tvrdoće. Pokazano je da dodavanje sintetičkog PEO u hitozanske filmove može smanjiti cenu proizvodnje i istovremeno zadržati mehanički integritet filmova.
PB  - Serbian Chemical Society, Belgrade
T2  - Journal of the Serbian Chemical Society
T1  - Processing and nanomechanical properties of chitosan/poly(ethylene oxide) blend films
T1  - Procesiranje i nanomehanička svojstva filma blendi hitozan/polietilen-oksid
EP  - 1733
IS  - 12
SP  - 1723
VL  - 77
UR  - https://hdl.handle.net/21.15107/rcub_technorep_2077
ER  - 

@article{
author = "Đokić, Jelena D. and Kojović, Aleksandar and Stojanović, Dušica and Marinković, Aleksandar and Vuković, Goran D. and Aleksić, Radoslav and Uskoković, Petar",
year = "2012",
abstract = "Chitosan-based films have found increasing implementation in a variety of fields, among which are as drug delivery carriers, in the packaging industry and as water purification filters. Therefore, in order to achieve mechanical integrity of such films while preserving processability and biocompatibility, chitosan-based films are fabricated in the forms of blends with poly(ethylene oxide) (PEO). A nano-indentation study was undertaken in order to investigate the nanomechanical properties and surface morphology of chitosan films in blends with various content of PEO. The results of differential scanning calorimetry, water uptake and nano-indentation revealed that films with an 80/20 blend ratio of chitosan/PEO showed the optimal values of reduced modulus and hardness. It appears that the incorporation of the synthetic PEO in chitosan films could lower the manufacturing costs while preserving the mechanical integrity of the films., Filmovi na bazi hitozana nalaze sve širu primenu u raznim oblastima između ostalog kao nosači lekova, u industriji ambalaže i kao filteri za prečišćavanje voda. Da bi se postigao mehanički integritet ovakvih filmova i zadržala procesabilnost i biokompatibilnost, filmovi na bazi hitozana pripremljeni su u formi blendi sa polietilen oksidom (PEO). Studija nanoindentacije urađena je u cilju proučavanja nanomehaničkih svojstava i površinske morfologije hitozanskih filmova u blendama sa različitim sadržajem PEO. Rezultati DSC-a, apsorpcije vode i nanoindentacije pokazali su da filmovi blendi sa odnosom 80/20 hitozana i PEO poseduju optimalne vrednosti redukovanog modula elastičnosti i tvrdoće. Pokazano je da dodavanje sintetičkog PEO u hitozanske filmove može smanjiti cenu proizvodnje i istovremeno zadržati mehanički integritet filmova.",
publisher = "Serbian Chemical Society, Belgrade",
journal = "Journal of the Serbian Chemical Society",
title = "Processing and nanomechanical properties of chitosan/poly(ethylene oxide) blend films, Procesiranje i nanomehanička svojstva filma blendi hitozan/polietilen-oksid",
pages = "1733-1723",
number = "12",
volume = "77",
url = "https://hdl.handle.net/21.15107/rcub_technorep_2077"
}

Đokić, J. D., Kojović, A., Stojanović, D., Marinković, A., Vuković, G. D., Aleksić, R.,& Uskoković, P.. (2012). Processing and nanomechanical properties of chitosan/poly(ethylene oxide) blend films. in Journal of the Serbian Chemical Society
Serbian Chemical Society, Belgrade., 77(12), 1723-1733.
https://hdl.handle.net/21.15107/rcub_technorep_2077

Đokić JD, Kojović A, Stojanović D, Marinković A, Vuković GD, Aleksić R, Uskoković P. Processing and nanomechanical properties of chitosan/poly(ethylene oxide) blend films. in Journal of the Serbian Chemical Society. 2012;77(12):1723-1733.
https://hdl.handle.net/21.15107/rcub_technorep_2077 .

Đokić, Jelena D., Kojović, Aleksandar, Stojanović, Dušica, Marinković, Aleksandar, Vuković, Goran D., Aleksić, Radoslav, Uskoković, Petar, "Processing and nanomechanical properties of chitosan/poly(ethylene oxide) blend films" in Journal of the Serbian Chemical Society, 77, no. 12 (2012):1723-1733,
https://hdl.handle.net/21.15107/rcub_technorep_2077 .

TY  - JOUR
AU  - Balać, Igor
AU  - Čolić, Katarina
AU  - Milovančević, Milorad
AU  - Uskoković, Petar
AU  - Zrilić, Milorad
PY  - 2012
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/2040
AB  - For a wide range of engineering structures such as ceramics, porous shape memory alloys, foam-like structures and thermal spray deposits, porous materials have been used. Recently, porous biocomposites for the applications to bone implants and hard tissue engineering have become increasingly important. The effect of matrix porosity on the elastic properties of particulate biocomposite was studied by two-and three-phase unit cell finite element models. A 3D FCC unit cell model of particulate composite with included matrix porosity is developed and compared with the simple theoretical models. It is found that the matrix porosity has noticeable influence on the composite elastic properties. The two-phase predictions overestimate the three-phase ones because of the physical threshold for three-phase model determined by the particle content.
AB  - Porozni materijali se koriste za široki spektar inženjerskih struktura napravljenih na bazi keramike, poroznih legura sa memorijskim efektom, penastih struktura, termički zaštitnih filmova. U skorije vreme primena poroznih biokompozita u inženjerstvu tvrdih tkiva kao i implanata kod koštanih defekata privlači posebnu pažnju. Uticaj matrične poroznosti na karakteristike elastičnosti čestičnih biokompozita analiziran je primenom metode konačnih elemenata upotrebom dvofaznog i trofaznog modela napravljenog na bazi reprezentativnog zapreminskog elementa - RZE. Razvijen je trofazni model RZE sa čestičnim ojačanjem raspoređenim u površinski centrirano kubnom rasporedu sa matričnom poroznošću oblika sfere, čiji su rezultati upoređeni sa jednostavnim analitičkom modelima. Primećeno je da matrična poroznost značajno utiče na karakteristike elastičnosti ovih vrsta kompozita. Rezultati dobijeni na osnovu dvofaznog modela imaju više vrednosti od onih dobijenih na osnovu trofaznog modela u skoro celom analiziranom opsegu usled fizičke granice za zapreminski udeo poroziteta kod trofaznog modela koja je očigledno određena vrednošću zapreminskog udela čestice ojačanja.
PB  - University of Belgrade - Faculty of Mechanical Engineering, Belgrade
T2  - FME Transactions
T1  - Modeling of the matrix porosity influence on the elastic properties of particulate biocomposites
T1  - Modeliranje uticaja matrične poroznosti na elastične osobine poroznih biokompozita
EP  - 86
IS  - 2
SP  - 81
VL  - 40
UR  - https://hdl.handle.net/21.15107/rcub_technorep_2040
ER  - 

@article{
author = "Balać, Igor and Čolić, Katarina and Milovančević, Milorad and Uskoković, Petar and Zrilić, Milorad",
year = "2012",
abstract = "For a wide range of engineering structures such as ceramics, porous shape memory alloys, foam-like structures and thermal spray deposits, porous materials have been used. Recently, porous biocomposites for the applications to bone implants and hard tissue engineering have become increasingly important. The effect of matrix porosity on the elastic properties of particulate biocomposite was studied by two-and three-phase unit cell finite element models. A 3D FCC unit cell model of particulate composite with included matrix porosity is developed and compared with the simple theoretical models. It is found that the matrix porosity has noticeable influence on the composite elastic properties. The two-phase predictions overestimate the three-phase ones because of the physical threshold for three-phase model determined by the particle content., Porozni materijali se koriste za široki spektar inženjerskih struktura napravljenih na bazi keramike, poroznih legura sa memorijskim efektom, penastih struktura, termički zaštitnih filmova. U skorije vreme primena poroznih biokompozita u inženjerstvu tvrdih tkiva kao i implanata kod koštanih defekata privlači posebnu pažnju. Uticaj matrične poroznosti na karakteristike elastičnosti čestičnih biokompozita analiziran je primenom metode konačnih elemenata upotrebom dvofaznog i trofaznog modela napravljenog na bazi reprezentativnog zapreminskog elementa - RZE. Razvijen je trofazni model RZE sa čestičnim ojačanjem raspoređenim u površinski centrirano kubnom rasporedu sa matričnom poroznošću oblika sfere, čiji su rezultati upoređeni sa jednostavnim analitičkom modelima. Primećeno je da matrična poroznost značajno utiče na karakteristike elastičnosti ovih vrsta kompozita. Rezultati dobijeni na osnovu dvofaznog modela imaju više vrednosti od onih dobijenih na osnovu trofaznog modela u skoro celom analiziranom opsegu usled fizičke granice za zapreminski udeo poroziteta kod trofaznog modela koja je očigledno određena vrednošću zapreminskog udela čestice ojačanja.",
publisher = "University of Belgrade - Faculty of Mechanical Engineering, Belgrade",
journal = "FME Transactions",
title = "Modeling of the matrix porosity influence on the elastic properties of particulate biocomposites, Modeliranje uticaja matrične poroznosti na elastične osobine poroznih biokompozita",
pages = "86-81",
number = "2",
volume = "40",
url = "https://hdl.handle.net/21.15107/rcub_technorep_2040"
}

Balać, I., Čolić, K., Milovančević, M., Uskoković, P.,& Zrilić, M.. (2012). Modeling of the matrix porosity influence on the elastic properties of particulate biocomposites. in FME Transactions
University of Belgrade - Faculty of Mechanical Engineering, Belgrade., 40(2), 81-86.
https://hdl.handle.net/21.15107/rcub_technorep_2040

Balać I, Čolić K, Milovančević M, Uskoković P, Zrilić M. Modeling of the matrix porosity influence on the elastic properties of particulate biocomposites. in FME Transactions. 2012;40(2):81-86.
https://hdl.handle.net/21.15107/rcub_technorep_2040 .

Balać, Igor, Čolić, Katarina, Milovančević, Milorad, Uskoković, Petar, Zrilić, Milorad, "Modeling of the matrix porosity influence on the elastic properties of particulate biocomposites" in FME Transactions, 40, no. 2 (2012):81-86,
https://hdl.handle.net/21.15107/rcub_technorep_2040 .