Evolution from micropinned to polymeric alloy structure of XLPE-PS: Improving electrical properties and mechanism

Abstract

This research investigates the transition from a micropinned to a polymeric alloy structure in crosslinked-polyethylene-polystyrene (XLPE-PS). Incorporating 2 wt% 10 μm PS particles into low-density polyethylene (LDPE) and crosslinking with 2 wt% dicumyl peroxide (DCP) forms XLPE-PS structures. The polymeric alloy structure, formed at 220°C extrusion, contrasts with the micropinned formed at 150°C. Morphological, thermo-structural, chemical, and crystal properties are examined to understand their impact on electrical properties and charge transport mechanisms. Results indicate that the polymeric alloy effectively resolves void/crack issues, whereas the micropinned exhibits phase separation. Both structures exhibit a benzene-crosslinked network, and variations in these structures lead to significant changes in thermo-structural, chemical, and crystalline properties. The polymeric alloy XLPE-PS shifts the polyethylene (PE) hkl crystal planes, confirming phase shift and optimal alloying. The structural alterations reveal deeper traps and higher densities in the polymeric alloy XLPE-PS, leading to significantly improved electrical properties, including reduced DC conductivity by up to 1.3 and 0.7 decades at 30 and 90°C, and increased DC breakdown strength by up to 40.34% and 16.17% at 30 and 90°C, respectively, compared with micropinned XLPE-PS. This research offers insights into stable high-voltage insulation development.