Preparation and properties of poly(lactic acid)/cellulolytic enzyme lignin/PGMA ternary blends

Poly(lactic acid)-based ternary blends consisting of poly(lactic acid) (PLA), cellulolytic enzyme lignin (CEL), and polyolefine grafting maleic anhydride (PGMA) were prepared by extrusion blending and the mechanical properties and the morphology of the ternary blends were investigated. It was found that the mechanical properties varied with various loading of the components in the blends. Compared to neat PLA, the tensile strength and the Young's modulus of the ternary blends were decreased, but the elongation at break and the impact strength were effectively improved. Scanning electron microscope observations revealed that the CEL plays a bridging role between PLA and PGMA, enhancing the miscibility between them and resulting in the improvement of ductility and toughness of the ternary blends. Considering the cost and performance, we obtained the optimal blend PLA/CEL/PGMA (80/20/20, w/w/w), of which the impact strength and the elongation at break were doubled as that of neat PLA, and the tensile strength remained moderate.