Strong and ultrafast stimulus-healable lignin-based composite elastomers with excellent adhesion properties

With the increased environmental issues, advanced high-performance and multifunctional polymeric materials derived from biomass have tremendous attention due to the great potential to replace their traditional petroleum-based counterparts. In this work, a series of lignin graft copolymers, lignin- graft -poly( n -butyl acrylate- co -acrylic acid) (Lig- g -P(BA- co -AA)), were rationally prepared via reversible addition-fragmentation chain transfer (RAFT) polymerization. These lignin-based copolymers demonstrate good thermal stability and tunable glass transition temperature ( T g ) values. The mechanical performance, including tensile strength , extensibility, Young's modulus , and toughness can be facilely adjusted by the BA/AA feed ratio and lignin content during polymerization. Owing to the extraordinary photothermal conversion ability of lignin, the Lig-B 550 copolymer, containing 11.8 wt% lignin content, shows excellent stimulus-healing behavior within 1 min with a 97.1 % healing efficiency under near-infrared (NIR) laser irradiation. Moreover, the Lig- g -P(BA- co -AA) copolymers exhibit remarkable adhesion property, broadening their potential applications in the adhesive area. This grafting strategy is versatile and efficient, conferring the resultant lignin-based composite elastomers with dramatically enhanced mechanical properties and unprecedented photothermal behavior, which can inspire the further development of strong lignin-based sustainable elastomers.