Composites of a biodegradable thermoplastic aliphatic polyester, polybutylene succinate adipate (PBSA), with granular corn starch were investigated for processability, mechanical and thermal properties, and biodegradability. The PBSA/starch films were prepared with starch contents of 5%–30% by weight and processed by blown film extrusion. Increasing the starch content led to an increase in modulus and decreases in tensile strength, elongation to break and toughness. The rate of biodegradation in soil, as measured by respirometry, increased significantly as the starch content was increased to 20% and then plateaued. Scanning electron microscopy revealed that the starch granules were embedded in the continuous-phase PBSA and that starch promotes the biodegradation of PBSA. Gel permeation chromatography indicated a molecular weight decrease for the PBSA after soil exposure and confirmed that biodegradation was enhanced by the presence of starch. The results demonstrated that the biodegradable PBSA/starch system has mechanical properties useful for blown film applications.
Посилання на статтю:
Processing, performance and biodegradability of a thermoplastic aliphatic polyester/starch system / Jo Ann Ratto, Peter J. Stenhouse, Margaret Auerbach, John Mitchell, Richard Farrell // Polymer. – 1999. – N 40. – P. 6777–6788.