Effects of Hydrolytic Degradation on the Mechanical Properties of Renewable Bioplastics: Poly(trimethylene malonate) and Poly(trimethylene itaconate)

摘要

Hydrolytic degradation of two renewable copolymers, poly(trimethylene malonate) (PTM) and poly(trimethylene itaconate) (PTI), was performed in aqueous solutions adjusted to pH values ranging approximately from 5.5 to 11. The influence of the degradation on the elastic modulus of these bioplastics was examined by a new atomic force microscopy (AFM) mode. Elastic modulus was monitored as a function of degradation time (100 to 10000 min) in DI water to determine changes. After degradation for one week the elastic modulus of PTI has decreased by 71 %. PTM was found to be hygroscopic. Due to significant swelling and uneven surfaces-in both the dry and wet state-PTM samples could neither be easily imaged nor its nanomechanical properties evaluated by AFM.