Fully biodegradable poly (lactic acid)/poly (butylene adipate-co-terephthalate) blends with highly toughness based on in situ interfacial compatibilization by functional Epoxy compound

Abstract

Synergistically integrating poly(butylene adipate-co-terephthalate) (PBAT) with polylactic acid (PLA) presents an economical strategy to develop biodegradable materials by leveraging their complementary characteristics. However, the inherent phase incompatibility between PBAT and induces severe interfacial defects, fundamentally limiting the development of high-strength biodegradable composites. In this study, glycidyl methacrylate (GMA) is grafted onto PBAT through reactive blending during the melting process, whereupon PLA/PBAT-g-GMA blends are prepared by means of an in-situ compatibilization approach, in an attempt to achieve PLA/PBAT blends with satisfactory comprehensive properties. The effects of PBAT content and GMA grafting rate on the interfacial compatibility, microstructure, mechanical properties, thermal performance, crystalline behavior and rheological processability of PLA/PBAT blends are investigated in detail. Systematic research has shown that the compatibility of PLA/PBAT blends has been significantly improved by implementing reactive compatibilization methods, and when the PBAT-g-GMA (2.84, the number refers to the grafting rate of GMA) content is 40%, the impact strength of the blend can reach 961 J/m without affecting rigidity, which indicates that our work proposes an effective approach to fabricate high-toughness PLA/PBAT blends through simple, environmentally friendly, and low-cost processing methods. Furthermore, the PLA/PBAT blends exhibit enhanced crystallization behavior while showing a slight decrease in thermal performance. The rheological analysis shows that the storage modulus, loss modulus, and complex viscosity significantly increase with the increase of PBAT content and GMA grafting rate, which improves processing performance of blends. SEM shows that as the grafting rate of GMA increases, the particle size distribution of PBAT becomes smaller and more uniform.