Efficient conversion of poly(butylene adipate-co-terephthalate) into covalent adaptable networks via a chain breaking–crosslinking strategy

Abstract

Poly(butylene adipate-co-terephthalate) (PBAT) is a widely used biodegradable polymer, but its application is limited by its poor mechanical properties and barrier properties. Herein, PBAT was extruded with polyols and isophorone diisocyanate on a twin-screw extruder to obtain PBAT covalent adaptable networks (CANs), in which chain breaking and crosslinking occurred. In the chain-breaking step, transesterification between polyols and PBAT chains introduced plenty of reactive hydroxyl groups and produced long-chain branched PBAT which was further crosslinked with diisocyanate to obtain crosslinked networks in the chain-crosslinking step. PBAT-CANs possessed higher mechanical properties, gas barrier, and creep resistance than PBAT, and maintained the favorable degradability and processability suitable for screw extrusion and hot-press processing. This work provides a highly-efficient method for enhancing the performance of PBAT.