Miscible Polymer Blends Based on Polycarbonate and a Copolyester.

A thorough study was made of the thermodynamic, melt processing, mechanical property, environmental stability, and gaseous sorption and transport behaviour of a model miscible blend system comprised of Polycarbonate, PC, and a copolyester made from 1,4-cyclohexane dimethanol and a mixture of isophthalic and terephthalic acids. Generally the mechanical properties of this blend relative to those often observed for immiscible mixtures, are quite good and data have been developed which suggest that the interactions between polymer blend components responsible for miscibility are also responsible for deviations in blend moduli, strength, density, ductility, Henrys Law portion of gas sorption, and in gas permeation rates, relative to those expected for purely additive behavior. this miscible blend system was found to exhibit some interesting chemical phenomena. When annealed just below its melting point, Tm, the copolyester was found to undergo crystallization induced chemical rearrangements, CICR, which resulted in abnormally high levels of crystallinity and crystalline melting points.