Blends of a Bottle-Grade Polyethylene Terephthalate Copolymer with a Liquid Crystalline Polymer. Part II: Thermal and Transport Properties

摘要

In this work the thermal and transport properties of dichloromethane in blends of a bottle-grade polyethylene terephthalate copolymer, PET, and a liquid crystalline polymer, LCP, were measured. Thermal characterizations of the blends were made by modulated differential scanning calorimetry and dynamic mechanical thermal analyses. An approximated LCP "bulk orientation" was also calculated by wide angle X-ray diffraction. The morphology was analyzed by scanning electron microscopy. The resulting sorption curves of pure PET, and the B20, B40 and B60 blends were sigmoid type curves, while the sorption curve of the B80 blend was a two-stage type curve. The diffusion coefficients of the B20 and B40 blends were found to be the lowest of all the blends. These low diffusivities were attributed to the occurrence of strong long-range and short-range interactions between the PET and the LCP in the B20 and B40 blends, and also to the perfection of the PET crystals in the B20 blend.