恭喜课题组博士生杨凯的文章“Enhancing electrical properties of impact polypropylene copolymer for ecofriendly power cable insulation by manipulating the multiphase structure through molten-state annealing”被知名期刊Composites Science and Technology接收。

The multi-phase structure and electrical properties evolution of impact polypropylene copolymer (IPC) during molten-state annealing (MSA) were investigated. Significant increases by about 17% and 30% in breakdown strength and charge injecting transition field strength were achieved respectively through proper MSA, which closely correlated with interactions among multiple phases in IPC. With ongoing MSA, ethylene-propylene random copolymer (EPR) was separated from block copolymer (EbP) or polypropylene (PP) matrix, and crystallizable EbP segments were drawn into PP matrix to form thicker lamellae. As a result, energy levels of deep and shallow trap increased with the increase in lamella thickness and the enhancement of interactions between amorphous PP and EPR chains, respectively. Moreover, the breakdown strength was found significantly depending on deep trap energy levels. Under 50 Hz AC voltage, electro-hole recombination was proposed to be the main origins of high-energy electrons rather than acceleration under electric field. The greater the energy level of the deep trap, the smaller the energy released by recombination, resulting in reduced probability of collision ionization and increased breakdown strength. This work provides a new comprehending into the electrical breakdown and its modification of IPC eco-friendly cable insulation.

Composites Science and Technology publishes refereed original articles on the fundamental and applied science of composites. The focus of the journal is on polymeric matrix composites with reinforcements/fillers ranging from nano- to macro-scale. CSTE encourages manuscripts reporting unique, innovative contributions to the materials science, physics, chemistry and applied mechanics aspects of advanced composites.