Effects of TESPT loading and mixing condition on properties of silica-filled HNBR cured with peroxide: Correlation of bound rubber content, viscoelastic and mechanical properties

Abstract

Peroxide-cured hydrogenated nitrile rubber (HNBR) reinforced with precipitated silica (PSi) was prepared with various loadings of Si-69 silane (TESPT). Two different mixing conditions, i.e., normal condition (low mixing temperature/short mixing time) and extreme condition (high mixing temperature/long mixing time), were employed for sample preparation. It was found that mixing at the extreme condition yielded significantly increased rubber-filler interaction. Unlike in sulphur curing system, the TESPT in peroxide curing gave an undesirable reduction in cure efficiency particularly more pronounced at high TESPT loadings. Such phenomenon was lowered at the extreme conditions.