STUDIES OF RIGID POLY(VINYL CHLORIDE) (PVC) COMPOUNDS .2. DETERMINATION OF THE FUSION LEVEL

Rigid poly(vinyl chloride) (PVC) compounds were prepared in a Haake to rque rheometer using various blending conditions. The fusion levels of processed compounds were evaluated by a capillary rheometer and diffe rential scanning calorimetry (DSC), based on the entrance pressure dro p and the heat of fusion, respectively. S-shaped fusion curves were ob tained. Starting temperature of the mixer, rotor speed, and totalized torque are the three major factors that affect the fusion level of PVC compounds blended in the Haake torque rheometer. All three parameters have a significant effect; however, totalized torque has the greatest effect and this can be characterized using a torque rheometer. Both c apillary rheological and DSC thermal analysis can be applied to determ ine the fusion level of a PVC compound. The morphological changes of t he various fusion processes were characterized by scanning electron mi croscopy (SEM). (C) 1995 John Wiley & Sons, Inc.