Naslov
Effect of gamma-irradiation and thermal aging on gas barrier of polyolephines

Autori
Klepac, Damir ; Ščetar, Mario ; Valić, Srećko ; Galić, Kata

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Proceedings MATBIM2012 / Debeaufort, Frédéric - Dijon, 2012

Skup
2nd International symposium International Meeting on packaging Material / Bioproduct Interactions

Mjesto i datum
Dijon, Francuska, 22.04.2012. - 25.04.2012

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
gamma-irradiation; polyolephines; thermal aging; oxygen permeability

Sažetak
Linear low density polyethylene (PE-LLD) and cast polypropylene (PPcast) films were exposed to γ- irradiation. The irradiation dose varied from 0 kGy (nonirradiated samples) to 200 kGy. A manometric method was used to investigate oxygen permeability of polyolephines. Structural changes were studied by differential scanning calorimetry (DSC), electron spin resonance (ESR) and Fourier transform infrared spectroscopy (FTIR). The results show that γ-irradiation slightly reduces oxygen permeability coefficient in both films. This reduction was associated with an increase in crystallinity. DSC thermograms revealed a decrease in PPcast melting temperature with irradiation dose, indicating a higher degradation compared to polyethylene. The observed peak in FTIR spectra for both samples at 1716 cm-1 corresponds to the stretching of the carbonyl and carboxylic groups which arise from the reaction of oxygen with the free radicals produced in the polymer matrix as a result of irradiation. Free radicals decay as a function of time was monitored by ESR spectroscopy. The samples were subjected to accelerated thermal aging during 48 and 96 hours at 80 °C. The decreasing of oxygen permeability, as a consequence of thermal aging was more pronounced in PE-LLD film. This effect was attributed to partial crystallization of amorphous PE-LLD. According to FT-IR spectra, no evidence for the oxidation process of thermally treated films was observed (no presence of carbonyl and carboxylic groups).

Izvorni jezik
Engleski

Znanstvena područja
Kemija, Prehrambena tehnologija

POVEZANOST RADA