Rheological and Fusion Behaviors of PVC Micro- and Nano-composites Evaluated From Torque Rheometer Data

Abstract

The effects of calcium carbonate (CaCO3) particle size on the fusion and rheological behaviors of rigid poly(vinyl chloride) (PVC) composites prepared in a Haake torque rheometer were investigated by means of torque data recorded during processing. Increasing the number of particles in the same blend volume by decreasing the particle size resulted in increasing frictional forces. This increase led in turn to increased fusion torque and decreased fusion time and temperature. The power-law-index values of the composites increased with decreasing particle size except for 25-nm CaCO3. The viscosities of all composites were found to decrease with shear rate; therefore, high pseudoplasticity was observed. At a particular rotor speed, viscosity of the composites decreased with decreasing particle size except for 25-nm CaCO3. The overall results showed that the particle size of CaCO3 altered the fusion characteristics and rheological behavior of PVC. J. VINYL ADDIT. TECHNOL., 16:223-228, 2010. (C) 2010 Society of Plastics Engineers