Influences of coagent hybrid ratios and silanes on viscoelastic properties of silica-filled HNBR

Abstract

Silica filled HNBR compounds were prepared, and modified with 2 different silanes, namely, mercapto silane (TESPT) and vinyl silane (VTEO). Because the HNBR was cured with peroxide, the 2 coagents (TRIM and ZDA) were used simultaneously as a hybrid system for a purpose of cure efficiency enhancement. Various composition ratios of TRIM to ZDA were used in association with 2 different silanes. Results of viscoelastic properties, as investigated by RPA2000 via oscillatory shear flow, suggest the different suitability of coagent hybrid ratio in the system with different silanes. Due to the released sulfur molecules from TESPT, a cure retardation phenomenon is resulted. The use of high ZDA composition leads to improved viscoelastic and cure properties in TESPT filled system. On the other hand, the system modified with VTEO reveals the synergistic effect of VTEO and TRIM, probably via a co-crosslink, resulting in the enhanced crosslink density, especially at high composition ratio of TRIM. © (2013) Trans Tech Publications, Switzerland.