Effect of blend ratio on cure characteristics, mechanical properties, oil resistance,  and ageing resistance of silica-filled ENR/NR blends

Adul Na Wichien; Chanin Ngudsuntear; Garry L. Rempel; Wanvimon Arayapranee

Authors

Adul Na Wichien Rubber Research Institute of Thailand, Department of Agriculture, Bangkok, 10900, Thailand
Chanin Ngudsuntear Department of Chemical Engineering, Kasetsart University, Bangkok, 10900, Thailand
Garry L. Rempel Department of Chemical Engineering, University of Waterloo, Ontario N2L 3G1, Canada
Wanvimon Arayapranee Department of Chemical and Material Engineering, Rangsit University, Patumthani, 12000, Thailand

Keywords:

epoxidized natural rubber, blend, resistance, mechanical properties

Abstract

The effects of blend ratio on cure characteristics, mechanical properties, morphology, and the resistance to oil, thermal ageing, and ozone of blends based on epoxidized natural rubber (ENR) and natural rubber (NR) have been investigated in the presence of silica selected as a reinforcing filler due to its unique characteristic to interact with ENR. The blend composition was varied from 0 to 100%. The results indicate that the Mooney viscosity increased whereas cure time (t₉₀) decreased with an increase of ENR in the blend. Due to better filler dispersion and greater crosslink density, the silica-filled ENR exhibited slightly better tensile properties, compared to silica-filled NR. The maximum value of tensile properties was obtained for at 50/50 (wt/wt) of ENR/NR blend. The observed changes in the mechanical properties of the blends were correlated with phase morphology as attested to by scanning electron microscopy (SEM). The results reveal that the oil and ozone resistances of the ENR/NR blend were increased with increasing ENR content. However, the resistances to degradation from thermal ageing and abrasion showed a reverse behavior in their respective blends.

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