Poly(1,4-cyclohexylenedimethylene 1,4-cyclohexanedicarboxylate): Influence of stereochemistry of 1,4-cyclohexylene units on the thermal properties

A series of poly(1,4-cyclohexylenedimethylene 1,4-cyclohexanedicarboxylate) (PCCD) samples, characterized by different cis/trans ratio of the 1,4-cyclohexanedicarbonyl unit, have been synthesized and analyzed by thermogravimetry (TGA), calorimetry (DSC), and X-ray diffraction (WAXD). The thermal stability results are good and are not affected by the stereochemistry of the 1,4-cyclohexylene units. On the other hand, the thermal transitions are notably influenced by the cis/trans content. With the increment of the trans content the polymer changes from completely amorphous to semicrystalline material. T-g, T-m, and crystallinity increase. These results suggest that the trans configuration induces a better chain packing and higher symmetry, improving the crystallizability of the samples. The effect of the molecular structure on the thermal properties is analyzed by using a statistical approach. From the effective correlations found between stereochemistry of the C-6 rings and transition temperatures it is possible to extrapolate that the configuration of 1,4-cyclohexylene ring deriving from 1,4-cyclohexanedicarboxylic acid or dimethyl 1,4-cyclohexanedicarboxylate results to be the main element responsible for the thermal properties. This is due to the high rigidity of the 1,4-cyclohexanedicarbonyl unit with respect to 1,4-cyclohexanedimethyleneoxy unit, deriving from the diol. (c) 2008 Wiley Periodicals, Inc.