Processing and characterization of poly(lactic acid) films plasticized with commercial adipates

Abstract

The high brittleness of Poly(lactic acid) is a major drawback for flexible food packaging applications. The aim of this work is to evaluate the potential use of commercial adipates as PLA plasticizers to obtain transparent films with enhanced mechanical properties. Processing conditions were optimized. The effect of plasticizers was characterized by a decrease on the glass transition temperature and an increase in PLA chains mobility, which induced crystallization on heating. Thermal stability was not significantly affected, and mechanical properties showed an increase in ductility with the plasticizer content. Oxygen transmission rate was also measured to evaluate the effect of the microstructures generated by the presence of these additives in PLA-based films. The monomeric adipate presented lack of homogeneity that makes films plasticized with this additive not useful for the intended application. Good compatibility was observed between polyadipates (up to 20 wt %) and the matrix, making them promising materials for biodegradable films manufacturing. © 2009 Wiley Periodicals, Inc.