Influence of molecular structure and stereochemistry of the 1,4-cyclohexylene ring on thermal and mechanical behavior of poly(butylene 1,4-cyclohexanedicarboxylate)

Poly(butylene 1,4-cyclohexanedicarboxylate), an aliphatic polyester with favorable properties, such as resistance to weather and potential biodegradability, has been synthesized with different cis/trans ratio of the 1,4-cyclohexylene ring. The samples show high degradation temperatures, independent of the stereochemistry of the aliphatic ring. Instead, glass transition temperature, crystallization and melting behavior are strongly influenced by the cis/trans ratio. The trans isomer, more rigid and symmetric than the cis, favors higher transition temperatures and crystallizability. The DMTA spectra present two secondary relaxations, attributed to the -(CH2)-unit and aliphatic ring motions, which can be beneficial for improving impact resistance properties. The physical properties are compared with those of PBT and PCCD.