Chemically recyclable, fully biobased polyolefins with performance parity to low-density polyethylene

Abstract

Plastics underpin modern society yet impose unsustainable burdens: petroleum consumption and environmental persistence. Developing chemically recyclable, biobased plastics with performance parity to conventional polymers represents a critical advance toward circular materials. Herein, we achieve this through molecular design of a structurally precise macrocyclic lactone derived from starch and castor oil. Homopolymerization affords high-molecular-weight polyolefins with strategically embedded ester linkages. Through a simple backbone hydrogenation strategy, the properties of such polyolefins (which may alternatively be classified as polyesters) can be dramatically tuned, converting them from elastomers into plastics. These linkages—uniformly positioned along the backbone—enable low-density polyethylene (LDPE)-comparable thermomechanical properties while serving as programmed break points. Crucially, these polyolefin plastics with a biomass content of up to 100 wt% could undergo quantitative degradation to telechelic diols/diacids under mild conditions, which were efficiently repolymerized via polycondensation to regenerate virgin materials. Owing to their favorable water vapor permeability and thermomechanical properties, these biobased polyolefins are ideal for use in packaging and agricultural films.