Thermal properties of blends of a thermotropic liquid crystalline copolyester of poly(hydroxy benzoic acid-co-ethylene terephthalate) and polyarylate

Thermal properties and transesterification reaction of blends of polyarylat e (PAr) and a thermotropic liquid crystalline polymer (LCP) were investigat ed by differential scanning calorimetry (DSC) and Fourier Transform infrare d (FT-IR) spectroscopy. In the thermogram of PAr-LCP blends, two glass tran sition temperatures (T(g)s) were observed. Phase behavior of the blends rev ealed that the LCP dissolved more in the Phr-rich phase than did the PAr in the LCP-rich phase, indicating partial miscibility between two polymers. T he polymer-polymer interaction parameter (chi(12)) was calculated, and rang ed from 0.069 to 0.076. In the calculation of the chi(12), the anisotropy o f the LCP was considered. After annealing, the two T(g)s of the blends were shifted toward the center. In the FT-IR spectroscopy study of the annealed PAr-LCP blends, three new characteristic peaks of the ester group were det ected. The DSC and FT-IR results suggested that transesterification reactio n between PAr and LCP occurred under the annealed condition.