Effects ofin-situfunctionalization of carbon nanotubes with bis(triethoxysilylpropyl) tetrasulfide (TESPT) and 3-aminopropyltriethoxysilane (APTES) on properties of epoxidized natural rubber-carbon nanotube composites

Composites of carbon nanotubes (CNT) and epoxidized natural rubber (ENR) were prepared by in-situ functionalization of CNT with two alternative silane coupling agents: bis(triethoxysilylpropyl) tetrasulfide (TESPT) and 3-aminopropyltriethoxysilane (APTES). The reactions of ENR molecules with the functional groups on CNT surfaces and with the silane molecules were characterized by Fourier transform infrared. Furthermore, cross-link density, relaxation behaviors, curing, mechanical, electrical, and morphological properties of pristine ENR and the ENR composites were investigated. Very low percolation thresholds, at CNT concentrations as low as 1 phr, were observed in the ENR–CNT and the ENR–CNT–TESPT composites. This might be attributed to improvements in the chemical linkages between ENR molecules and functional groups on CNT surfaces that led to a homogenous dispersion of CNTs in the ENR matrix, with loose CNT agglomerates. POLYM. ENG. SCI., 55:2500–2510, 2015. © 2015 Society of Plastics Engineers