A comprehensive study on thermal/electrical conduction, mechanical and curing properties of silicone rubber nanocomposites contained exfoliated-surface modified h-BNs

In current work, hexagonal boron nitride (h-BN) was firstly exfoliated and then surface modified by vinyltriethoxysilane (VTES) at different concentrations. The success of silane grafting was evaluated using FTIR, XRD, TGA and XPS analysis. Thereafter, the modified and unmodified h-BNs were incorporated in to silicone rubber matrix and comprehensively examined for final performances. Silane modification of the exfoliated h-BN made the nanocomposite less thermal stable than the rest. In contrast, the thermal conductivity of the modified nanocomposite enhanced by 42.2 and 550% compared to the unmodified nanocomposite and SR. Although, the presence of h-BNs (i.e. both of the modified and unmodified) improved considerably the electrical resistivity of SR but, silane treated nanocomposites showed lower electrical resistivity than unmodified ones (19.7%). FE-SEM images confirmed improved interfacial bonding between exfoliated/silanized h-BN to SR matrix that was arisen from co-curing of vinyl groups in VTES and SR chains. This happening improved filler-polymer adhesion and made the mechanical property of the modified nanocomposite outstanding with higher storage modulus, tensile strength and Tg compared to the SR (i.e. 127%, 26% and 10 degrees C, respectively). The contact angle increased from 92.8o for SR to 107.6 for modified nanocomposite which is mostly desired in microelectronic applications.