Toughening Polylactide with Phase‐Separating Complex Copolymer Architectures

Abstract

Polylactide (PLA) is a commercially produced potentially sustainable plastic that holds promise to replace petroleum‐sourced materials. Unfortunately, the brittle nature of PLA limits its current utility to disposable packaging. Melt blends of PLA and a rubbery material can rubber toughen the plastic, but often require the addition of a compatibilizer and generate opaque materials. Current efforts explore using block and graft copolymers with a majority PLA block and minority rubbery block that phase separate on the nanometer length scale to rubber toughen PLA. With these complex architectures, the polymer matrix, the minor rubbery component, and the compatibilizer are present in one molecule. Many block and graft copolymers rely on non‐sustainable rubbery blocks, which limits the sustainability of these materials. Recent work has utilized polyisoprene (PI) as the sustainable backbone for PLA graft copolymers. Post‐polymerization functionalization and copolymerization of PI provides a method to create fully sustainable PLA/PI graft copolymers that phase separate on the nanometer‐scale to make potentially tough, sustainable plastics. image