Tailoring the structures and properties of biodegradable poly(lactic acid)/poly(butylene adipate-co-terephthalic...

In conventional elastomer-toughened PLA blends, the huge sacrifice in strength and modulus due to poor compatibility is a major problem plaguing such materials. In this work, oxide-epoxy-graphene (SGO-GMA) nanoparticles that can chemically react with both components of PLA/PBAT blends are prepared to serve as compatibilizer by "thiol-ene click" reaction. It is found that SGO-GMA tends to be dispersed in the PBAT phase thermodynamically. However, the one-step process, SGO-GMA is dispersed in both PBAT and PLA phases because of the chemical reaction limiting its migration, and the crystallization rate of the PLA phase is significantly increased. In contrast, in the two-step process, SGO-GMA is anchored at the interface by the in-situ reaction between epoxy groups in GMA with PLA and PBAT. Consequently, the mechanical properties of the samples prepared using a two-step process demonstrate a significant advantage. Specifically, incorporating 1 wt% SGO-GMA into PLA/PBAT blends results in simultaneous enhancements in tensile strength, elongation at break, and impact strength by 7.9%, 40.7%, and 57.1%, respectively. The improved mechanical properties that based on the roles functionalized GO compatibilization are expected to facilitate the application of PLA in tissue engineering materials, in vivo and in vitro medical devices and other fields.