TY  - JOUR
AU  - Petronijevic, Ivan M.
AU  - Cerovic, Dragana D.
AU  - Dudic, Dusko A.
AU  - Dojčilović, Jablan R.
AU  - Dojčinović, Biljana
AU  - Pergal, Marija
PY  - 2018
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/2289
AB  - In this paper, a new simple and environmentally friendly treatment technique for obtaining polymer nanocomposites with appropriate dielectric properties has been presented. Sheets of isotactic polypropylene and atactic polystyrene were immersed in 3 saturated water solutions of alkali metal salts (LiCl, NaCl, and KCl) at 2 fixed temperatures (23 degrees C and 90 degrees C), and 3 DC electrical potentials (+4kV, -4kV, and ground potential) were applied. A quantification of alkali metals in the polymer sheets was conducted by inductively coupled plasma optic emission spectrometry. The obtained concentration values were from 7.3810(-9)mol/cm(3) to 1.2510(-7)mol/cm(3). The qualitative analysis of potassium distribution in the polymer matrix was conducted by time-of-flight secondary ion mass spectrometry cross-sectional record. The relative dielectric constant (epsilon) of samples was investigated in the frequency range from 20Hz to 9MHz at the constant temperature of 22 degrees C. Stable values of epsilon in fully measured frequency range were observed for both pure and treated samples. Next, the results of the dielectric spectroscopy measurements were compared and established the kind of treatment that provided the highest value of epsilon. The relationship between the concentrations of alkali metals and the values of relative dielectric constant was determined for the samples obtained by a treatment at 90 degrees C and +4kV.
PB  - Wiley, Hoboken
T2  - Polymers For Advanced Technologies
T1  - Dielectric spectroscopy of nanocomposites based on iPP and aPS treated in the water solutions of alkali metal salts
VL  - 29
IS  - 6
SP  - 1826
EP  - 1833
DO  - 10.1002/pat.4289
ER  - 

@article{
author = "Petronijevic, Ivan M. and Cerovic, Dragana D. and Dudic, Dusko A. and Dojčilović, Jablan R. and Dojčinović, Biljana and Pergal, Marija",
year = "2018",
abstract = "In this paper, a new simple and environmentally friendly treatment technique for obtaining polymer nanocomposites with appropriate dielectric properties has been presented. Sheets of isotactic polypropylene and atactic polystyrene were immersed in 3 saturated water solutions of alkali metal salts (LiCl, NaCl, and KCl) at 2 fixed temperatures (23 degrees C and 90 degrees C), and 3 DC electrical potentials (+4kV, -4kV, and ground potential) were applied. A quantification of alkali metals in the polymer sheets was conducted by inductively coupled plasma optic emission spectrometry. The obtained concentration values were from 7.3810(-9)mol/cm(3) to 1.2510(-7)mol/cm(3). The qualitative analysis of potassium distribution in the polymer matrix was conducted by time-of-flight secondary ion mass spectrometry cross-sectional record. The relative dielectric constant (epsilon) of samples was investigated in the frequency range from 20Hz to 9MHz at the constant temperature of 22 degrees C. Stable values of epsilon in fully measured frequency range were observed for both pure and treated samples. Next, the results of the dielectric spectroscopy measurements were compared and established the kind of treatment that provided the highest value of epsilon. The relationship between the concentrations of alkali metals and the values of relative dielectric constant was determined for the samples obtained by a treatment at 90 degrees C and +4kV.",
publisher = "Wiley, Hoboken",
journal = "Polymers For Advanced Technologies",
title = "Dielectric spectroscopy of nanocomposites based on iPP and aPS treated in the water solutions of alkali metal salts",
volume = "29",
number = "6",
pages = "1826-1833",
doi = "10.1002/pat.4289"
}

Petronijevic, I. M., Cerovic, D. D., Dudic, D. A., Dojčilović, J. R., Dojčinović, B.,& Pergal, M.. (2018). Dielectric spectroscopy of nanocomposites based on iPP and aPS treated in the water solutions of alkali metal salts. in Polymers For Advanced Technologies
Wiley, Hoboken., 29(6), 1826-1833.
https://doi.org/10.1002/pat.4289

Petronijevic IM, Cerovic DD, Dudic DA, Dojčilović JR, Dojčinović B, Pergal M. Dielectric spectroscopy of nanocomposites based on iPP and aPS treated in the water solutions of alkali metal salts. in Polymers For Advanced Technologies. 2018;29(6):1826-1833.
doi:10.1002/pat.4289 .

Petronijevic, Ivan M., Cerovic, Dragana D., Dudic, Dusko A., Dojčilović, Jablan R., Dojčinović, Biljana, Pergal, Marija, "Dielectric spectroscopy of nanocomposites based on iPP and aPS treated in the water solutions of alkali metal salts" in Polymers For Advanced Technologies, 29, no. 6 (2018):1826-1833,
https://doi.org/10.1002/pat.4289 . .

TY  - JOUR
AU  - Pavlović, Vera P.
AU  - Krstić, Jugoslav
AU  - Scepanovic, M. J.
AU  - Dojčilović, Jablan R.
AU  - Minić, Dragica M.
AU  - Blanusa, J.
AU  - Stevanović, Suzana
AU  - Mitic, V.
AU  - Pavlović, Vladimir B.
PY  - 2011
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/808
AB  - In this article, in order to obtain tetragonal nanocrystalline BaTiO3, structural investigations of mechanically activated BaTiO3 powder have been performed. A mercury porosimetry analysis and scanning electron microscopy method have been applied for determination of the specific pore volume, porosity and microstructure morphology of the samples. The lattice vibration spectra of nonactivated and activated powders, their phase composition, lattice microstrains and the mean size of coherently diffracting domains were examined by Raman spectroscopy and the X-ray powder diffraction method. The average crystal structure of obtained nanocrystalline powders, estimated from X-ray diffraction data, gave evidence of retained, but slightly sustained tetragonality of powders, even for particles as small as similar to 30 nm. Raman spectroscopy also gave clear evidence for local tetragonal symmetries, in particular through the presence of a band at similar to 307 cm(-1).
PB  - Elsevier Sci Ltd, Oxford
T2  - Ceramics International
T1  - Structural investigation of mechanically activated nanocrystalline BaTiO3 powders
VL  - 37
IS  - 7
SP  - 2513
EP  - 2518
DO  - 10.1016/j.ceramint.2011.03.064
ER  - 

@article{
author = "Pavlović, Vera P. and Krstić, Jugoslav and Scepanovic, M. J. and Dojčilović, Jablan R. and Minić, Dragica M. and Blanusa, J. and Stevanović, Suzana and Mitic, V. and Pavlović, Vladimir B.",
year = "2011",
abstract = "In this article, in order to obtain tetragonal nanocrystalline BaTiO3, structural investigations of mechanically activated BaTiO3 powder have been performed. A mercury porosimetry analysis and scanning electron microscopy method have been applied for determination of the specific pore volume, porosity and microstructure morphology of the samples. The lattice vibration spectra of nonactivated and activated powders, their phase composition, lattice microstrains and the mean size of coherently diffracting domains were examined by Raman spectroscopy and the X-ray powder diffraction method. The average crystal structure of obtained nanocrystalline powders, estimated from X-ray diffraction data, gave evidence of retained, but slightly sustained tetragonality of powders, even for particles as small as similar to 30 nm. Raman spectroscopy also gave clear evidence for local tetragonal symmetries, in particular through the presence of a band at similar to 307 cm(-1).",
publisher = "Elsevier Sci Ltd, Oxford",
journal = "Ceramics International",
title = "Structural investigation of mechanically activated nanocrystalline BaTiO3 powders",
volume = "37",
number = "7",
pages = "2513-2518",
doi = "10.1016/j.ceramint.2011.03.064"
}

Pavlović, V. P., Krstić, J., Scepanovic, M. J., Dojčilović, J. R., Minić, D. M., Blanusa, J., Stevanović, S., Mitic, V.,& Pavlović, V. B.. (2011). Structural investigation of mechanically activated nanocrystalline BaTiO3 powders. in Ceramics International
Elsevier Sci Ltd, Oxford., 37(7), 2513-2518.
https://doi.org/10.1016/j.ceramint.2011.03.064

Pavlović VP, Krstić J, Scepanovic MJ, Dojčilović JR, Minić DM, Blanusa J, Stevanović S, Mitic V, Pavlović VB. Structural investigation of mechanically activated nanocrystalline BaTiO3 powders. in Ceramics International. 2011;37(7):2513-2518.
doi:10.1016/j.ceramint.2011.03.064 .

Pavlović, Vera P., Krstić, Jugoslav, Scepanovic, M. J., Dojčilović, Jablan R., Minić, Dragica M., Blanusa, J., Stevanović, Suzana, Mitic, V., Pavlović, Vladimir B., "Structural investigation of mechanically activated nanocrystalline BaTiO3 powders" in Ceramics International, 37, no. 7 (2011):2513-2518,
https://doi.org/10.1016/j.ceramint.2011.03.064 . .

TY  - JOUR
AU  - Miličević, Dejan
AU  - Trifunović, Saša
AU  - Mudrinić, Tihana
AU  - Leskovac, Andreja
AU  - Ignjatović, Nenad
AU  - Dojčilović, Jablan
AU  - Suljovrujić, Edin
PY  - 2010
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/7023
AB  - U ovom radu ispitivan je uticaj gama zračenja na molekulsku masu i staklasti prelaz poli-L-laktida (PLLA). S obzirom da je PLLA pri izlaganju visokoenergijskom zračenju sklon kidanju lanaca i velikoj degradaciji, promene u molekulskoj masi su određene primenom gel propusne hromatografije (GPC). Radijaciono-indukovane promene u staklastom prelazu su ispitane pomoću diferencijalno skenirajuće kalorimetrije (DSC). Prividna aktivaciona energija za staklasti prelaz, ΔH*, određena je na osnovu zavisnosti temperature staklastog prelaza, Tg, od brzine zagrevanja. Kidanje lanaca, uzrokovano zračenjem, glavni je razlog opadanja Tg i ΔH* sa apsorbovanom dozom. Izazvane promene u molekulskoj masi i temperaturi staklastog prelaza odigravaju se na predvidljiv i prilično precizan način. Stoga, gama zračenje može biti korišćeno nesamo za sterilizaciju nego i za dobijanje ovog biomaterijala poželjnih karakteristika.
AB  - The influence of gamma radiation on the structure and glass transition behaviour of poly-L-lactide (PLLA) has been studied. Since PLLA exposed to high-energy radiation in the presence of air is prone to chain scission reactions and large degradation, changes in molecular weight were obtained by the gel permeation chromatography (GPC). Alterations in the glass transition behaviour were investigated by differential scanning calorimetry (DSC). The apparent activation energy, ΔH*, for the glass transition was determined on the basis of the heating rate dependence of the glass transition temperature, Tg. Our findings support the fact that chain scission is the main reason for the decrease of Tg and ΔH* with the absorbed dose. At low doses, despite large changes in molecular weight, only small alterations are observed in the glass transition temperature and apparent activation energy. Further increase in the absorbed dose introduces not only significant changes in the molecular weight but also in the glass transition temperature and the activation energy. Such glass transition behavior is a manifestation of a well-known effect of molecular weight on Tg, postulated by the Fox–Flory equation. However, all the observed alterations are small and tolerable at absorbed doses required for sterilization (up to 25 kGy in most circumstances). Furthermore, this study reveals that the radiation-induced changes in the molecular weight and the glass transition temperature occur in a predictable and fairly accurate manner. Therefore, gamma radiation can be used not only for sterilization but also for tailoring desirable end-use properties of PLLA based implants.
PB  - Association of Chemical Engineers of Serbia
T2  - Hemijska industrija
T1  - Uticaj gama zračenja na molekulsku masu i staklasti prelaz PLLA
T1  - The Structure and Glass Transition Behaviour of PLLA under the Influence of Gamma Radiation
VL  - 64
IS  - 4
SP  - 275
EP  - 281
DO  - 10.2298/HEMIND100329020M
ER  - 

@article{
author = "Miličević, Dejan and Trifunović, Saša and Mudrinić, Tihana and Leskovac, Andreja and Ignjatović, Nenad and Dojčilović, Jablan and Suljovrujić, Edin",
year = "2010",
abstract = "U ovom radu ispitivan je uticaj gama zračenja na molekulsku masu i staklasti prelaz poli-L-laktida (PLLA). S obzirom da je PLLA pri izlaganju visokoenergijskom zračenju sklon kidanju lanaca i velikoj degradaciji, promene u molekulskoj masi su određene primenom gel propusne hromatografije (GPC). Radijaciono-indukovane promene u staklastom prelazu su ispitane pomoću diferencijalno skenirajuće kalorimetrije (DSC). Prividna aktivaciona energija za staklasti prelaz, ΔH*, određena je na osnovu zavisnosti temperature staklastog prelaza, Tg, od brzine zagrevanja. Kidanje lanaca, uzrokovano zračenjem, glavni je razlog opadanja Tg i ΔH* sa apsorbovanom dozom. Izazvane promene u molekulskoj masi i temperaturi staklastog prelaza odigravaju se na predvidljiv i prilično precizan način. Stoga, gama zračenje može biti korišćeno nesamo za sterilizaciju nego i za dobijanje ovog biomaterijala poželjnih karakteristika., The influence of gamma radiation on the structure and glass transition behaviour of poly-L-lactide (PLLA) has been studied. Since PLLA exposed to high-energy radiation in the presence of air is prone to chain scission reactions and large degradation, changes in molecular weight were obtained by the gel permeation chromatography (GPC). Alterations in the glass transition behaviour were investigated by differential scanning calorimetry (DSC). The apparent activation energy, ΔH*, for the glass transition was determined on the basis of the heating rate dependence of the glass transition temperature, Tg. Our findings support the fact that chain scission is the main reason for the decrease of Tg and ΔH* with the absorbed dose. At low doses, despite large changes in molecular weight, only small alterations are observed in the glass transition temperature and apparent activation energy. Further increase in the absorbed dose introduces not only significant changes in the molecular weight but also in the glass transition temperature and the activation energy. Such glass transition behavior is a manifestation of a well-known effect of molecular weight on Tg, postulated by the Fox–Flory equation. However, all the observed alterations are small and tolerable at absorbed doses required for sterilization (up to 25 kGy in most circumstances). Furthermore, this study reveals that the radiation-induced changes in the molecular weight and the glass transition temperature occur in a predictable and fairly accurate manner. Therefore, gamma radiation can be used not only for sterilization but also for tailoring desirable end-use properties of PLLA based implants.",
publisher = "Association of Chemical Engineers of Serbia",
journal = "Hemijska industrija",
title = "Uticaj gama zračenja na molekulsku masu i staklasti prelaz PLLA, The Structure and Glass Transition Behaviour of PLLA under the Influence of Gamma Radiation",
volume = "64",
number = "4",
pages = "275-281",
doi = "10.2298/HEMIND100329020M"
}

Miličević, D., Trifunović, S., Mudrinić, T., Leskovac, A., Ignjatović, N., Dojčilović, J.,& Suljovrujić, E.. (2010). Uticaj gama zračenja na molekulsku masu i staklasti prelaz PLLA. in Hemijska industrija
Association of Chemical Engineers of Serbia., 64(4), 275-281.
https://doi.org/10.2298/HEMIND100329020M

Miličević D, Trifunović S, Mudrinić T, Leskovac A, Ignjatović N, Dojčilović J, Suljovrujić E. Uticaj gama zračenja na molekulsku masu i staklasti prelaz PLLA. in Hemijska industrija. 2010;64(4):275-281.
doi:10.2298/HEMIND100329020M .

Miličević, Dejan, Trifunović, Saša, Mudrinić, Tihana, Leskovac, Andreja, Ignjatović, Nenad, Dojčilović, Jablan, Suljovrujić, Edin, "Uticaj gama zračenja na molekulsku masu i staklasti prelaz PLLA" in Hemijska industrija, 64, no. 4 (2010):275-281,
https://doi.org/10.2298/HEMIND100329020M . .

TY  - JOUR
AU  - Pavlović, Vera P.
AU  - Popović, D.
AU  - Krstić, Jugoslav
AU  - Dojčilović, Jablan R.
AU  - Babić, Biljana M.
AU  - Pavlović, Vladimir B.
PY  - 2009
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/588
AB  - The influence of mechanical activation in a planetary ball mill on the change of the structure of BaTiO3 powders has been investigated. The particle size distribution of the nonactivated and activated samples was measured by a particle dimension laser analyzer. The mercury porosimetry method has been applied for determination of the surface area of the samples, bulk density, specific pore volumes, total porosity and the pore size distributions. Formation of paramagnetic centers and the change of the IR active modes was investigated by EPR and IR measurements. Semi-quantitative comparison of the BaCO3 and OH- group presence in IR spectra was calculated. The investigation showed that mechanical activation of BaTiO3 has a pronounced influence on the change of the powder particles structure and enables establishing the directions of possible BaTiO3 ceramics materials properties prognosis according to the synthesis-structure correlation.
PB  - Elsevier
T2  - Journal of Alloys and Compounds
T1  - Influence of mechanical activation on the structure of ultrafine BaTiO3 powders
VL  - 486
IS  - 1-2
SP  - 633
EP  - 639
DO  - 10.1016/j.jallcom.2009.07.008
ER  - 

@article{
author = "Pavlović, Vera P. and Popović, D. and Krstić, Jugoslav and Dojčilović, Jablan R. and Babić, Biljana M. and Pavlović, Vladimir B.",
year = "2009",
abstract = "The influence of mechanical activation in a planetary ball mill on the change of the structure of BaTiO3 powders has been investigated. The particle size distribution of the nonactivated and activated samples was measured by a particle dimension laser analyzer. The mercury porosimetry method has been applied for determination of the surface area of the samples, bulk density, specific pore volumes, total porosity and the pore size distributions. Formation of paramagnetic centers and the change of the IR active modes was investigated by EPR and IR measurements. Semi-quantitative comparison of the BaCO3 and OH- group presence in IR spectra was calculated. The investigation showed that mechanical activation of BaTiO3 has a pronounced influence on the change of the powder particles structure and enables establishing the directions of possible BaTiO3 ceramics materials properties prognosis according to the synthesis-structure correlation.",
publisher = "Elsevier",
journal = "Journal of Alloys and Compounds",
title = "Influence of mechanical activation on the structure of ultrafine BaTiO3 powders",
volume = "486",
number = "1-2",
pages = "633-639",
doi = "10.1016/j.jallcom.2009.07.008"
}

Pavlović, V. P., Popović, D., Krstić, J., Dojčilović, J. R., Babić, B. M.,& Pavlović, V. B.. (2009). Influence of mechanical activation on the structure of ultrafine BaTiO3 powders. in Journal of Alloys and Compounds
Elsevier., 486(1-2), 633-639.
https://doi.org/10.1016/j.jallcom.2009.07.008

Pavlović VP, Popović D, Krstić J, Dojčilović JR, Babić BM, Pavlović VB. Influence of mechanical activation on the structure of ultrafine BaTiO3 powders. in Journal of Alloys and Compounds. 2009;486(1-2):633-639.
doi:10.1016/j.jallcom.2009.07.008 .

Pavlović, Vera P., Popović, D., Krstić, Jugoslav, Dojčilović, Jablan R., Babić, Biljana M., Pavlović, Vladimir B., "Influence of mechanical activation on the structure of ultrafine BaTiO3 powders" in Journal of Alloys and Compounds, 486, no. 1-2 (2009):633-639,
https://doi.org/10.1016/j.jallcom.2009.07.008 . .