Sustainable chitin-derived elastomers via grafting strategy with tunable mechanical and adhesion properties.

With increasing environmental awareness and the pursuit of sustainable development goals, environmentally friendly sustainable thermoplastic elastomers (TPEs) derived from natural resources are highly desired to replace traditional TPEs. However, preparing sustainable TPEs with high mechanical properties and multifunctionality from biobased feedstocks remains a significant challenge. In this work, a series of chitin-graft-poly(acrylamide-co-2-ethylhexyl acrylate) (Chitin-g-P(AM-co-EHA)) copolymers were synthesized through reversible addition-fragmentation chain transfer (RAFT) polymerization. The tensile strength of Chitin-g-P(AM-co-EHA) copolymers can be tuned over a wide range from 1.0 to 7.3 MPa by adjusting the chitin and PAM contents. Benefiting from the brush-like architecture, Chitin-g-P(AM-co-EHA) copolymer exhibits improved mechanical properties over its linear counterparts. Moreover, these Chitin-g-P(AM-co-EHA) copolymers show good adhesion performance on different substrates. The shear strength can achieve 7.5 MPa for Chitin0.8-PAM50, which is high enough for commercial applications. The combination of chitin and grafting strategy can promote the development of strong chitin-based sustainable elastomers. This approach can be further utilized to design novel high-performance biobased elastomers and adhesives derived from natural resources.