The simultaneous introduction of low and high molecular weight of biodegradable Poly(diethylene glycol adipate)s to Plasticize and Toughen Polylactide

Abstract

Plasticization and toughness of polylactide (PLA) are of interesting due to its poor machinability and brittleness. Here, low and high macromolecular weight of Poly(diethylene glycol adipate)s (L-PDEGA and H-PDEGA) were used to plasticize and toughen PLA simultaneously. The results showed that the mechanical properties of PLA remained almost unchanged when only 5 wt% L-PDEGA was added. However, H-PDEGA were effective in lowering the glass transition temperatures as well as in increasing the elongation at break and the impact strength. Compared with neat PLA, the crystallinity of PLA increased with increasing H-PDEGA content. When 20 wt% H-PDEGA was added, the impact strength and the elongation at break increased from 3.1 kJ/m2 and 5.6 % of neat PLA to 68.3 kJ/m2 to 272.4 %, respectively. Additionally, morphological study revealed that the fracture behavior of PLA had been changed from brittle to ductile after H-PDEGA incorporated. The results of rheological analysis showed that the storage modulus and complex viscosity in the melt state of the blends were decreased compared with that of neat PLA.