Morphology and enzymatic degradation of thermoplastic starch-polycaprolactone blends

Abstract

This study's aim was to evaluate the effect of processing conditions on the morphology and enzymatic degradation of 50/50 (w/w) thermoplastic starch–polycaprolactone blends. The blends, produced from native potato starch, glycerol, and polycaprolactone in a melt mixer using different mixing speeds and temperatures, were cocontinuous, and the blends were very homogeneous. Enzymatic hydrolysis was performed using Bacillus licheniformis alpha-amylase and Aspergillus niger glucoamylase on both milled and intact samples. The thin layer of polycaprolactone (≈ 5 μm) formed on the surface of the thermoplastic starch–polycaprolactone blends during compression molding strongly reduced the rate of enzymatic hydrolysis. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2594–2604, 1999