Liquid crystalline polymer blends with stabilized viscosity

Abstract

The rheology of blends of thermotropic liquid crystalline copolyester co(hydroxybenzoate-isophthalate-hydroquinone) (HIQ) and polyetherimide were studied at different temperatures. As a result of the anisotropic-to-isotropic transition, the viscosity of the biphasic HIQ was found to be able to compensate that of the host polyetherimide at proper composition when the temperature increased or decreased in the capillary rheometer study. The 33% HIQ blend had almost stabilized viscosity between 350 and 370 degrees C, whereas the 15% HIQ blend did not have stabilized viscosity. For the nonisothermal spiral molding trial, the 33% HIQ blend stabilized at a mean length of 21 inches (53 cm) with a standard deviation of 2.1 inch (5.3 cm) when the melt temperature increased by 30 Celsius degrees from 340 to 370 degrees C.