Designing novel semi‐aromatic polyesters with dimethyl 3,3′‐bibenzoate

Melt polycondensation of dimethyl 3,3′‐bibenzoate (3,3'BB) with various linear and cycloaliphatic diols enabled the synthesis of a series of semi‐aromatic polyesters. Size exclusion chromatography analysis confirmed high molecular weight (Mn > 20 kg mol−1). Compression molding resulted in ductile films and further established molecular weights desirable for mechanical performance. 1H NMR spectroscopy confirmed polymer structure and retainment of the cis/trans ratios for the cyclohexyldimethylene‐based polyesters before and after polymerization. Thermogravimetric analysis revealed high onset of weight loss temperatures for the novel semi‐aromatic polymers (Td,5% > 380 °C). Differential scanning calorimetry and dynamic mechanical analysis were used to determine glass transition temperatures and melting temperatures. Further evaluation of these thermal transitions against previously synthesized 4,4'BB, 3,4'BB, and isophthalate‐based polymers elucidated the structure–property relationships of these systems. © 2023 Society of Industrial Chemistry. Polycondensation of regioisomeric dimethyl bibenzoates with a diverse array of aliphatic spacers provided novel polyesters with enhanced thermomechanical properties.