Physical and Biodegradation Properties of Poly(L-lactide)-b-poly (ethylene glycol)-b-poly(L-lactide)/Polypropylene Blends for Potential Use as Partially Biodegradable Plastics

Abstract

This study investigates the thermal, morphological, mechanical, and biodegradation properties of blends comprising poly(L-lactide)-b-poly (ethylene glycol)-b-poly(L-lactide) triblock copolymer (PLLA-PEG-PLLA) and polypropylene (PP) compared to the PLLA/PP blends. All the blends were prepared using a melt-blending technique. The ability to crystallize and the thermal stability of the PLLA-PEG-PLLA were enhanced by blending PP, whereas these properties were not enhanced for the PLLA. The crystallinity of PLLA-PEG-PLLA increased from 20.4% to 23.5-38.8%. The temperature at maximum decomposition rate (Td,max) of PLLA end-blocks increased from 310 °C to 327-332 °C. The phase compatibility between the PLLA-PEG-PLLA and PP was better than between the PLLA and PP, as indicated by the smaller size of dispersed PP particles in the PLLA-PEG-PLLA matrix. The PLLA-PEG-PLLA/PP blends showed greater flexibility, higher wettability, and faster biodegradation rates than the PLLA/PP blends. This suggests that these PLLA-PEG-PLLA/PP blends may be used as flexible and partially biodegradable plastics.