Preparation and Properties of Toughened PLA / PBAT Blends Based on EVA and Multi‐Functional Epoxy Chain Extender

ABSTRACT The effects of ethylene‐vinyl acetate copolymer (EVA) and multi‐component epoxy chain expander (ADR) on the performance of PLA/PBAT blend were investigated by preparing PLA/PBAT/EVA blends and PLA/PBAT/EVA/ADR blends through melt blending method. The mechanical properties, morphology, thermal behavior, and rheological properties were studied. The addition of EVA had a slight improvement on the impact strength of PLA, while the tensile strength had a decrease and elongation at break had significant increase. The microstructure of PLA/PBAT/EVA also showed a sea‐island morphology, the EVA had a small impact on the rheological property of PLA/PBAT blend. When introduced ADR in the PLA/PBAT/EVA blend, the morphology showed that the interface interaction of the blends was been significantly improved. As a result, the rheological property, including the complex viscosity, storage modulus and loss modulus increased remarkably compared with PLA. The impact strength of PLA/PBAT/EVA/ADR blends had a significant improvement, the highest impact strength reaches 51.99 kJ/m2, which is 22.3 times higher than that of PLA. The elongation at break of the blend maintains in the range of 400%–500% with tensile strength 43.5 MPa. Furthermore, the PLA/PBAT/EVA/ADR blends also showed an improved of heat resistance and thermostability compared with PLA.