A Facile Method for Generating Designer Block Copolymers from Functionalized Lignin Model Compounds

We report a versatile scheme for the synthesis of renewable homopolymers and block copolymers (BCPs) via the functionalization and subsequent controlled reversible addition fragmentation chain transfer (RAFT) polymerization of vanillin, a possible lignin derivative. The vanillin-based homopolymers exhibit glass transition temperatures (120 degrees C) and degradation temperatures (>= 300 degrees C) comparable to polystyrene, indicating that these and similar polymers may serve as suitable alternatives to petroleum-based materials. Additionally, by employing controlled polymerization techniques, a vanillin-based homopolymer was chain-extended with lauryl methacrylate, a model fatty acid-derived monomer, to generate nanostructured BCPs. As one example, these elastomeric copolymers can self-assemble into a body-centered cubic array of vanillin-based nanospheres in a poly(lauryl methacrylate) matrix, which we demonstrated via small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM) analysis. This work provides a blueprint for the controlled polymerization of phenolic lignin model compounds and their subsequent chain extension with various biobased comonomers, enabling the de novo design and generation of new homopolymers and BCPs with tunable properties.