Rheological properties of dynamically vulcanized poly(vinyl chloride)/epoxidized natural rubber thermoplastic elastomers: effect of processing variables

摘要

The melt rheological behavior of poly(vinyl chloride)/epoxidized natural rubber (PVC/ENR) thermoplastic elastomers (TPEs) was studied with a special reference to the effect of dynamic vulcanization, apparent shear rate and temperature using a twin screw capillary rheometer. PVC/ENR TPEs were compounded with a HAAKE twin screw extruder (WCT100). At a particular temperature it was found that the apparent viscosity decreased with increased in apparent shear rate following a pseudoplastic behavior, thus indicating that the dynamically vulcanized TPEs are processible as thermoplastics. The elastic phenomena was investigated by calculating the die swell which was found to be affected by the apparent shear rate and processing temperature. The extrudate surfaces at different apparent shear rates were studied by means of optical microscopy. It was observed that as apparent shear rate increases the extrudate surface exhibits a higher degree of deformation, the extent of which is also dependent on the sulfur concentration. (C) 1999 Elsevier Science Ltd. All rights reserved. [References: 28]