Unveiling the effect of enhanced interfacial compatibility on the mechanical properties of PLA/PBAT blends

Polylactic acid (PLA)/polybutylene adipate terephthalate (PBAT) blend is a fully degradable polymer blend with balanced strength and toughness. However, the performance of PLA/PBAT blends deteriorates significantly after undergoing physical aging. In this work, dicumyl peroxide (DCP) and methyl methacrylate-glycidyl methacrylate copolymer (P(MMA-co-GMA)) were used respectively for reactive compatibilization by dynamic vulcanization. The effects of dynamic vulcanization on the interfacial compatibility and thus on the mechanical properties of PLA/PBAT blends were evaluated using nanomechanical mapping. Results show that the degree of interfacial compatibilization can be determined by the interface length of microscopic Young's moduli distribution between PLA and PBAT. A longer interfacial length indicates an enhanced interfacial interaction between the components in the blend, which leads to improved macroscopic mechanical properties. Moreover, the improvement of interfacial compatibility allows the PLA/PBAT blends to maintain higher mechanical properties after physical aging, which provides an experimental basis for the design of PLA-based blends with both high mechanical properties and resistance to physical aging.