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

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 H-1 and C-13 NMR. The weight-average molecular weights (M-w) of the PKs were 2.6-15.0 x 10(3) g/mol, and those of all PEKs were approximately 1.0 x 10(3). The 10% degradation temperatures of the PKs and PEKs were 340-400 degrees 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 (T-g) in the range 250-297 degrees C, while T-g of PK (octyl side-chain) was 157 degrees C and those of the PEKs were 73-127 degrees C.

Automated summary

In this study, bio-based aromatic polyketones (PKs) and polyetherketones (PEKs) were synthesized using electrophilic substitution reaction. The introduction of alkoxy side-chains at the hydroxyl groups of divanillic acid prior to polymerization allowed for the successful synthesis of soluble polymers with determined chemical structures. The PKs exhibited high glass transition temperatures (T-g) and thermal stability compared to the PEKs, highlighting the importance of side-chain structures in determining properties of these materials.