Preparation and characterization of poly(lactic acid)/elastomer blends prepared by melt blending technique

Abstract

Poly(lactic acid) (PLA) and biodegradable elastomer were melt blended and molded in an injection molding machine. The crystallinity, viscoelasticity, thermal and mechanical properties of the molded blend and annealed blend samples were studied. Differential scanning calorimetry was used to evaluate the crystallinity and thermal property of all the samples. It was found that the melting temperature decreased as the amount of elastomer increased. Additionally, the presence of elastomer tended to increase the crystallinity of PLA at 10 and 20 wt%. The injection molding led to the diminishing of neat PLA crystallinity to be 20.79%; however, annealing could recover it to be 29.94%. This result was supported by x-ray diffraction and dynamic mechanical analysis tests. The complex viscosity and storage modulus of PLA melt decreased upon addition of elastomer. The elongation at break increased as the content of elastomer increased. However, the Young’s modulus and tensile strength decreased severely due to the addition of elastomer.