Improving thermal/electrical properties of silicone rubber nanocomposite using exfoliated boron nitride nano sheets made by an effective/novel exfoliating agent

Abstract

In this work, boron nitride nano sheets (BNNSs) were prepared by exfoliation of h-BNs using mono ethylene glycol (MEG) as a novel exfoliating agent. For comparison, isopropyl alcohol (IPA)/water mixture was also used for exfoliation of h-BNs. It was found that using MEG caused preparing nano layers with higher yield and lower thickness compared to the IPA/water mixture. Thereafter, silicon rubber nanocomposites contained 3 and 5 wt% of pure and exfoliated BNNSs were prepared and evaluated for thermal and electrical performances. It was found that h-BNs and exfoliated-BNs drastically enhanced thermal conduction of SR. The silicon rubber contained 5 wt% of the h-BN and exfoliated-BNs illustrated around 20 times higher thermal conductivities compared to pure SR. Exfoliation of h-BNs had negligible effect on improvement of thermal properties, however, it caused 5.7 and 2.3 times enhancement in the electrical volume resistivity compared to the pristine SR and pure h-BN containing nanocomposite, respectively. Both of the BNNSs caused improvement in the heat dissipation performances of SR matrix, however, the exfoliated one with MEG showed better performances. Based on the results, it was claimed that mono ethylene glycol could improve exfoliation of h-BNs and enhance the performances of silicon rubber.