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Poly(lactic acid) (PLA) is a biodegradable polymer that exhibits high elastic modulus, high mechanical strength, and feasible processability. However, high cost and fragility hinder the application of PLA in food packaging. Therefore, this study aimed to develop flexible PLA/acetate and PLA/chitosan films with improved thermal and mechanical properties without the addition of a plasticizer and additive to yield extruder compositions with melt temperatures above those of acetate and chitosan. PLA blends with 10, 20, and 30 wt% of chitosan or cellulose acetate were processed in a twin-screw extruder, and grain pellets were then pressed to form films. PLA/acetate films showed an increase of 30°C in initial degradation temperature and an increase of 3.9 % in elongation at break. On the other hand, PLA/chitosan films showed improvements in mechanical properties as an increase of 4.7 % in elongation at break. PLA/chitosan film which presented the greatest increase in elongation at break proved to be the best candidate for application in packaging.

Cell wall hemicelluloses are useful in various industries due to their ability to form edible and biodegradable films with plasticizerssuch as glycerol. The objective of this research was toextract hemicelluloses from Caesalpina pulcherrima and Tamarindus indica, produce film blends from them, and evaluate their properties and their product development potential. The extraction process providedyields of 25% galactomannan (GalCp) from C. pulcherrimaand 20% xyloglucan (XilTi) from T. indica. The apparentM w obtained by GPC were 4.35 x 10 6 g/mol and 2.03 x 10 6 g/mol for GalCp and XilTi respectively. The ratio of mannose/galactose in GalCp determined by 13 C NMR was (2 : 1), while the ratio of glucose/xylose/galactose in XilTi obtained by 13 C NMR was (1.0: 1.2: 1.0). All filmogenic solutionsfrom these hemicelluloses showed non-Newtonian rheological behavior at 25 °C. The IR spectra were consistent with the presence of GalCp and XilTi and were fully assigned.Galactomannan film exhibited a higher permeability to moisture than xyloglucan and the blends.All films showed less than 20% opacity; thus, they were relatively transparent. Thermogravimetric analysis indicated that the blend films had good thermal stability.The use of theseblends permits a wider range of properties to be obtained than the hemicelluloses alone.Thus, these materials may serve asuseful biodegradable and environmentallyfriendly materials for food packaging applications.

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