Preparation of all biomass lignin-based thermoplastic elastomers by ARGET ATRP

Lignin, which acts as the matrix in plant cell walls, has versatile potential to substitute synthetic polymers. To construct all-biomass lignin-based copolymers, lauryl methacrylate (LMA) from plant oil and isobornyl methacrylate (IBOMA) from pine sap were utilized to compose side chains on the lignin macro-initiator (OL-Br) via ARGET ATRP. A series of grafted copolymers with different molar ratios of LMA, IBOMA, and OL-Br were successfully synthesized and compared with each other through various characterization techniques. It turned out that the synthesized lignin graft copolymers have much higher molecular weights than that of linear copolymers. Besides that, the molar ratio of IBOMA/LMA in the grafted chains was positively related to the glass transition temperature of copolymer since the domain of PIBOMA is less flexible than that of PLMA. Owing to the existence of lignin, the prepared copolymer not only exhibited a good mechanical property as a typical elastomer but also showed an apparent UV absorption ability. Furthermore, a remarkable adhesive property of the copolymer had been also verified on various substrates. Therefore, it demonstrated that these obtained all-biomass lignin-based copolymers were able to partially replace synthetic elastomers and adhesives from petroleum.