Synthesis and characterization of bio-based aromatic polyketones and polyetherketones derived from divanillic acid

Abstract Bio-based aromatic polyketones (PKs) and polyetherketones (PEKs) were synthesized by the electrophilic substitution reaction of alkoxylated divanillic acid (R-DVA) and 2,2′-dimethoxybiphenyl or diphenylether. Alkoxy side-chains were introduced at the hydroxyl groups of DVA prior to polymerization. Polymerizations were carried out in a phosphorus pentoxide (P2O5)/methanesulfonic acid (MsOH) system. DVA-based PKs and PEKs were soluble in common organic solvents including chloroform and dimethylsulfoxide, and their chemical structures were determined by 1H and 13C-NMR. The weight-average molecular weights (Mw) of the PKs were 2.6–15.0×103 g/mol, and those of all PEKs were approximately 1.0×103. The 10% degradation temperatures of the PKs and PEKs were 340–400 °C. Dynamic mechanical analysis showed that the PKs and PEKs were amorphous. The PKs with methyl to butyl side-chains exhibited high glass transition temperatures (Tg) in the range 250–297 °C, while Tg of PK (octyl side-chain) was 157 °C and those of the PEKs were 73–127 °C.