The Balanced Insulating Performance and Mechanical Property of PP by Introducing PP‑<i>g</i>‑PS Graft Copolymer and SEBS Elastomer

The PP/PP-<i>g</i>-PS/SEBS blends are prepared by melt extrusion in order to improve both insulating properties and toughness of PP. SEBS is used to reduce the rigidity of PP, while the insulating properties are improved by adding PP-<i>g</i>-PS without decreasing mechanical properties. The microstructure of PP blends is carefully investigated by SEM, DMA, XRD, and DSC. It is interesting to find that a core–shell dispersion phase formed in the blend with the adding of PP-<i>g</i>-PS, and the size of core is decreased while the thickness of shell is increased with further increasing volume of PP-<i>g</i>-PS. Due to this special structure, the nucleation ability of SEBS is decreased. Meanwhile, the rigid segments and compatibilization effect of PP-<i>g</i>-PS not only increased the glass transition temperature of both PP and SEBS, but also enhanced their adhesion. Therefore, the electrical properties were increased without decreasing the mechanical properties of the blends. Consequently, an insulation material with excellent mechanical properties was obtained