ADMET polymerization of bio-based biphenyl compounds†
Four biphenyl monomers derived from vanillin or eugenol were synthesized and polymerized by the ADMET methodology. The biphenyl compounds were produced by enzymatic dimerization of 2-methoxy-4-methylphenol, methyl vanillate, vanillin and eugenol. Further chemical modifications of the obtained dimers such as transesterification, Wittig reaction or allylation led to α,ω-dienes. The reactivity of these bio-based monomers towards ADMET polymerization employing several catalysts was investigated. Only oligomers were obtained when the diallylated compound was employed. The polymers based on dieugenol and the bis-unsaturated diester exhibit good thermal stability and Tg at 17 and 54 °C, respectively. Polymerization of the divinyl compound obtained by the Wittig reaction of divanillin showed a reasonable molar mass of 30 000 g mol−1, a high Tg at around 160 °C and thermostability with a 5% weight loss occurring at 380 °C.