Comparison of viscoelastic behaviour in silica filled cured and uncured CPE/NR blends with various mixing time

Abstract

Blends of 30-phr silica filled elastomeric chlorinated polyethylene (CPE) and natural rubber (NR) at the blend composition ratio of 80/20 CPE/NR were prepared with various mixing time from 120 to 600 s. Viscoelastic behaviours of cured and uncured blends were determined using two rheometers with different shear modes, i.e., the oscillatory rheometer (Rubber Process Analyser, RPA2000) and the rate-controlled capillary rheometer (Goettfert Rheotester 2000). Results obtained reveal that the viscoelastic behaviour of blends is influenced by the formation of silica transient network, particularly in cured blends. Mixing time affects viscoelastic properties of vulcanised blends to some extent which is due probably to the high extent of thermal degradation, but plays no significant role in viscoelastic properties of unvulcanised blends. The superimposition of oscillatory and steady shear results is possible when the elastic component is eliminated from the results. © Appl. Rheol.