Reprocessable Biobased Statistical and Block Copolymer Methacrylic-Based Vitrimers with a Shape Memory Effect AITranslate

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DOI：https://doi.org/10.1021/acsapm.3c02515

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Transitioning to a circular bioeconomy requires shifting away from conventional petroleum-based thermosets to recyclable biobased materials. We developed reprocessable and shape-memory biobased vitrimers with controlled architecture and enhanced creep resistance. A series of prepolymers of lignin-based vanillin methacrylate (VMA), with a mixture of vegetable oil-derived methacrylic esters with an average alkyl side chain length of 13 units (C13MA), and glycidyl methacrylate (GMA) were synthesized: statistical copolymer poly(C13MA-co-vMA), block copolymer poly(C13MA-block-VMA), and statistical terpolymer poly(C13MA-co-VMA-co-GMA). Reversible addition–fragmentation chain-transfer (RAFT) polymerization allowed control over the backbone structure of statistical and block copolymers with similar overall molecular weights and compositions. Vitrification via aldehyde-functional VMA units with isophorone diamine enabled dynamic imine crosslinking, while adding the epoxy-functional GMA into the statistical terpolymer precursor enabled hybrid static–dynamic crosslinking networks. Vitrimers showed excellent retention of thermomechanical properties after 4× reprocessing cycles. Microphase separation was confirmed in the “hard–soft” type of block vitrimers. While statistical vitrimers showed comparable tensile properties, self-assembled block vitrimers exhibited poor tensile strength. Additionally, we compared the creep control using microphase separation and a hybrid network. Both methods reduced creep (up to 84%), but hybrid crosslinking caused significantly slower stress relaxation. A temperature-triggered shape memory effect was incorporated into the statistical vitrimer with two shape-programming cycles. Combining C13MA and VMA presents a rich platform for greener vitrimers with highly tunable properties and functionalities.