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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. Tg, Tm, 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 C6 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. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 619–630, 2008

SynopsisIn this work the reactions taking place during melt mixing of bisphenol-A polycarbonate (PC) with poly(ethy1ene terephthalate) (PET) were studied by selective degradation of PC sequences, solubility tests, and IR spectroscopy. It was found that exchange reactions between PC and PET took place, contrary to what has been previously suggested by other authors. Kinetic constants were evaluated from intrinsic viscosity measurements of PET blocks. The reaction rate was slow when only the Sb catalyst (residues of the PET polymerization) were present, but it was significantly accelerated by the addition of Ti(OBu1,. In the presence of the latter catalyst, other side reactions, leading to discoloration and gas evolution, took place.

Cover: The properties of poly(butylene 1,4-cyclohexanedicarboxylate) can be easily modulated by controlling the cis/trans ratio of the cycloaliphatic unit, as can be seen in the cover picture. The crystalline phase perfection increases with an increasing trans percentage. The mechanical relaxations at low temperatures, which improve the impact properties, depend on the cis/trans ratio. Further details can be found in the article

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