Pe-Sodyum Kazeinat ve Pe-Kitosan Karışımlarından Biyobozunur Film Eldesi ve Değişik Plastikleştirici ve Uyumlaştırıcıların Etkisinin İncelenmesi
Özet
In this study, low density polyethylene (PE)/sodium caseinate (SC), PE/chitosan (CH) and PE/SC+CH (HYB) mixtures were prepared. The ratios 5% , 15% for SC-based films, 10%, 15% for chitosan-based films, 7,5% SC+ 7,5% CH for HYB-based films were used. The effects of three different platicizers (glycerol (G), sorbitol (S), polyethylene glycol (P)) were investigated and they were added in equal amounts to the amount of biopolymer. Maleic anhydride grafted polyethylene (PE-g-MA) was used as compatibilizer, 5%, 10% and 15% of biopolymer ratio was added to the films with 15% biopolymer ratio. All films were produced in two stages. The mixtures were turned into pellets in the twin screw extruder by melt-mixing method, then the films were produced with a hot press. The visual, flowability, chemical, mechanical, hydrophobic, thermal, morphological, barrier, seal strength, biodegradation and antibacterial properties of the films were investigated. All films look like a single structure. Melt flow index decreased with increasing concentration of SC and CH into PE. Melt flow index of HYB film was between 15SC and 15CH films. Melt flow index of 15SC, 15CH and 15HYB increased with the addition of plasticizers and decreased with the compatibilizer. The molecular interaction was not observed between PE-SC and PE-CH by Fourier transform infrared spectroscopy. The electrostatic interaction was identified between SC and CH in HYB film. There was a slight interaction with the addition of plasticizers and the interaction was also proven by the tensile test with the addition of PE-g-MA. Tensile strength (TS) decreased with the incorporation of SC and CH into PE and it increased about 30% compared to 15SC film with the addition of HYB. There was no significant change in TS of SC-based films with the addition of plasticizers but, TS of CH and HYB-based films reduced. GLY was the most effective plasticizer in SC-based films, PEG was in CH and HYB-based films. While there was no change at 15CH film with only 5% of PE-g-MA and HYB-based films with the addition of all concentrations of PE-g-MA, TS and flexibility of the other films showed in an increasing tendency. Contact angle (CA) reduced with incorporation of SC and CH into PE. CA of HYB film was between 15SC and 15CH films. CA increased with the addition of plasticizer, decreased with the incorporation of PE-g-MA. PE has a single degradation curve, PE-SC, PE-CH and PE-HYB films have two stages. Thermal stability decreased with the addition of plasticizers. The degradation temperatures of the films increased with the incorporation of PE-g-MA. Phase separation was observed in the films plasticized by PEG. Heteregenous structure was observed in SEM images with the addition of SC, CH and HYB into PE. Heteregenous structure tended an improving with the addition of plasticizers and PE-g-MA. Water vapor permeability (WVP) increased with the addition of SC, CH and HYB into PE. The plasticized films by PEG were obtained the lowest WVP among the plasticizers. WVP did not show any effect on SC-based films with the addition of compatibilizer and it was generally in reducing trend on CH and HYB-based films. Oxygen transmission rate decreased about 45-50% with the addition of SC and CH into PE, it was obtained between SC and CH in HYB film. Plasticizer addition was more effective in CH and HYB-based films. There was no major change with the compatibilizer. Seal strength decreased about 90% with the addition of SC, CH and HYB. There was no significant effect on SC and CH-based films with the addition of plasticizer, it particularly increased in HYB-based films with addition of GLY. Seal strength increased with addition of compatibilizer. CH-based films degraded more slowly than SC-based films in the biodegradation test. The highest degradation was 15% in 15SC and 15SC plasticized by SOR films at the end of 120 days. Degradation increased with the plasticizers and decreased with the addition of compatibilizer. The highest antibacterial activity was obtained in 15CH film. The mixture films obtained with the addition of SC, CH and HYB into PE could be an alternative to PE films for food packaging applications.
