The effect of exfoliation on the breakdown strength of polystyrene boron nitride composites

Research on polymer nanocomposites promises to create a new class of materials with enhanced dielectric properties. This paper reports on the study of polystyrene systems filled with hexagonal boron nitride (BN) nanoparticles. The polymer nanocomposite materials were produced using a solvent blending procedure, where some of the materials were produced using dichloromethane (DCM) as the solvent and others using isopropyl alcohol (IPA). The breakdown strength was measured at different loading levels; the breakdown strength was found to decrease at the 5 wt% loading level, but increased again with 10 wt% and higher loadings of BN. The effect of exfoliation by solvent choice and sonication on the breakdown strength was investigated; sonication in IPA produced the best results. However, micrographs obtained from the scanning electron microscope show no apparent change of the dispersion of BN in the sonicated systems with the different solvents.