Adição de quitosana em laminados biodegradáveis de amido e poli (ácido lático) produzidos por extrusão plana

Abstract

Currently, one of the major environmental problems is the accumulation of synthetic plastics in the environment. It is a fact that they have a wide applicability in many industry sectors due their good mechanical and barrier properties coupled with low cost. Furthermore alternatives should be studied and developed to decline this problem. In this sense, the use of blends containing biodegradable polymers like starch and poly (lactic acid) (PLA) has gained considerable attention, especially for the food packaging production. Current research has also highlighted the use of chitosan because its antimicrobial activity, biodegradability and applicability in the production of active biodegradable food packaging. The objective of this work was to produce cassava starch and PLA sheets incorporated with chitosan by flat extrusion process, and evaluate the mechanical, water vapor barrier and antimicrobial properties. The incorporation of chitosan in the starch/PLA sheets decreased significantly the tensile strength, Young's modulus, elongation at break and density. In addition, the scanning electron microscopy images showed the formation of non-homogeneous mixtures with the presence of pores between the blend compounds, and this fact affected the water vapor barrier properties increasing water vapor permeability, solubility and diffusion coefficients. Chitosan did not provide antimicrobial activity against Staphylococcus aureus and Escherichia coli in the concentrations employed in this work. It was possible to conclude that although the incorporation of chitosan to the starch/PLA sheets has not contributed to obtain materials with suitable properties, it was able to produced them by flat extrusion process in pilot scale. The use of chitosan can be viable with their purification and incorporation by surface crosslinking.