Main Article Content
This study aimed to prepare environmentally friendly packaging films with light, moisture, and oxygen barrier properties from poly(lactic acid) (PLA), natural rubber (NR) and modified chitosan or chitosan graft-poly acrylamide-2-methyl propane sulfonic acid (chitosan-g-PAMPs, Cg) blend. Various ratios of NR and Cg (NR:Cg) were blended in the latex stage. After drying, each NR:Cg was blended with PLA via a melt mixing process using single screw extruder and film blowing machine. It was found that NR and Cg blends were miscible in the latex stage. The elongation at break of the blends decreased with Cg content. After mixing with PLA, the morphology of the blends showed coarse surface with small particles of NR and Cg dispersed in the PLA matrix. The size of the NR:Cg particles found in the blends became smaller than that of the initial particles indicating the partial compatibility of NR:Cg and PLA blend components. The compatibility of the NR:Cg and the remaining NR:Cg particles may contribute to the improvement of the elongation at break and toughness properties of the PLA films. Moreover, the addition of NR:Cg improved the UV-vis transition, moisture and oxygen protection of PLA films. On the other hand, all blends showed lower glass transition temperatures (Tg) and lower cold crystallization temperatures (Tcc) than the pure PLA films while the percent of crystallinity increased. It can be concluded that NR:Cg is partially compatible and may contribute to the chain movement and inducing crystallinity of PLA films.
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