Rheological and spiral mold flow measurements were made on blends of a chlorinated poly (vinyl chloride) (CPVC) compound and a thermotropic liquid crystalline copolyester of p‐hydroxybenzoic acid/poly (ethylene terephthalate) (60/40), hereafter referred to as LCC, at 210°C. Several interesting flow phenomena have been observed. While the shape of the flow curve (i.e., G′ vs. ω; G″ vs. ω) of LCC is solidlike, those of the blends are pseudoplastic. The dynamic viscosity of the blends increases as the concentration of LCC increases. However, the shear viscosity of the blends is reduced with LCC and may be described using the relationship of additivity of fluidity. Although the melt elasticity of the blends is increased with the concentration of LCC, the extrudate swell of the blends after extrusion from a capillary is decreased. This phenomenon, however, is complicated. A Theological analysis based on an idealized runner system is used to describe the spiral flow length as a function of the Theological properties of the molten polymers and also the operating conditions. The relative improvement of the spiral flow length of the CPVC compound due to blending with LCC could be correlated with the power‐law fluid model at high shear rates.

The mechanical properties of squeezed flow films were measured on blends of a chlorinated poly(viny1 chloride) (CPVC) compound and a thermotropic liquid crystalline copolyester of p-hydroxybenzoic acid/poly(ethylene terephthalatel (60/40), hereafter referred to as LCC. CPVC is immiscible with LCC. The most serious and unique problem of liquid crystalline polymers is their tendency to fibrillate when fabricated into films and injection molded parts, primarily because of a high degree of mechanical anisotropy. It has been found that the mechanical anisotropy of LCC and blends could be lessened using nonisother-ma1 squeezing equibiaxial extension flow. The maximum tensile properties of LCC are achieved when processed in the vicinity of 260°C. For blends of CPVC containing LCC, the mechanical properties are dependent on the processing temperature and compositions. Blends with no more than 20 wt% of LCC exhibit significant increases in tensile properties. This is due to the possibility of frozen-in macroscopic biaxial orientation of LCC in the blends during the nonisothermal squeezing flow. Within the range of processable temperatures, the reinforcement of CPVC due to the incorporation of LCC can be achieved at a temperature below the optimum processing temperature of LCC, although the thermal history of blends never reaches that temperature.