Aromatic Polymethacrylates from Lignin‐Based Feedstock: Synthesis, Thermal Properties, Life‐Cycle Assessment and Toxicity

Abstract

There is currently a great need for rigid, high‐performance and processable bio‐based polymers and plastics as alternatives to the fossil‐based materials used today. Here, we report on the straightforward synthesis and polymerization of lignin‐derived methacrylate monomers based on the methyl esters of syringic, vanillic, and 4‐hydroxybenzoic acid, respectively. The corresponding homopolymethacrylates exhibit high glass transition temperatures (Tgs) at 106, 128, and 197 °C, respectively. Rheological properties and thermal stability up to at least 277 °C indicate that these polymers are melt‐processable. In addition, copolymers with methyl methacrylate are prepared to further vary and tune the polymer properties. An integrated ex‐ante and prospective life‐cycle assessment of key environmental impact parameters indicates similar or only slightly higher values compared to well‐established fossil‐based methyl methacrylate. Moreover, the toxicity towards human HeLa cell lines compares well with that of poly(methyl methacrylate). Hence, the potential availability of lignin‐derived acids, combined with the straightforward and potentially upscalable monomer synthesis, make these rigid polymers appealing alternatives towards bio‐based high‐Tg thermoplastic materials with low toxicity.