Characterization of biodegradable polymers by inverse gas chromatography. III. Blends of amylopectin and poly(L‐lactide)

Abstract

AbstractThe morphology changes and surface thermodynamics of blends of amylopectin (AP)–poly(L‐lactide) (PLA) were investigated over a wide range of temperatures and compositions using the inverse gas chromatography method. Twenty‐five solutes were selected such as alkanes, acetates, oxy, halogenated, and six‐member ring families. They provided a variety of specific interactions with the blends' surface. The morphology showed two regions, some others showed a de‐polymerization above 130°C. These zones enabled the estimation of Tg and Tm of AP, PLA, and the blends. Blending AP with PLA caused a decrease in AP's Tg value due to the reduction of the degree of crystallinity of the blend. Exothermic values of χ23 were obtained indicating the compatibility of AP and PLA at all temperatures and weight fractions of AP–PLA. The miscibility was favored at 75%AP, only 25%AP–75%PLA composition influenced the degree of crystallinity. The dispersive component of the surface energy of the blends ranged from 16.09 mJ/m2 for the pure AP as high as 58.36 mJ/m2 at 110°C when AP was mixed with PLA in a 50–50% ratio. The surface energy was at its highest value when the composition was 75% of AP, in good agreement with χ23 values. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012