Structure-property Relationships of Series Copolymers with Well-defined Sequence Lengths

In 1975 Roviello and Sirigu reported the properties of a series of polyesters which were prepared by incorporating a rigid and a flexible segment in the repeating unit. It perhaps the first example of the preparation of copolymers with well-defined sequence lengths. Recently, the crystal structures of some related copolymers were established by X-ray diffraction (XRD). However, the relationships between the polymer chain structures and the polymer properties, such as, thermal properties, mechanical properties, gas permeability and surface properties, etc. are still not clear. In order to get a better understanding of structure-property relationships, it is necessary to investigate on these copolymers with well-defined sequence lengths and sequence distributions. For this purpose, we have synthesized a series of copolymers composed of two parts, the rigid part is 2, 2-bis-hydroxyphenyl-hexafluoropropane (6FBA) or bisphenol A (BA) and the flexible part is different lengths of methylene segments (aliphatic sequence). The structure-property relationships are studied using XRD and differential scanning calorimeter (DSC).