茂金属聚乙烯改性低密度聚乙烯介电性能与机械强度

为提高聚乙烯电缆料的击穿强度和机械性能,将少量茂金属聚乙烯(MPE)与普通低密度聚乙烯(LDPE)共混,用电声脉冲法(PEA)测量直流预压短路后的残余空间电荷量;详细研究了共混物的体积电阻率、直流击穿强度、直流预压反极性击穿电压和机械强度.实验结果表明:当MPE含量为1wt%时,能有效提高共混物的击穿强度和机械强度,但同时降低了体积电阻率和材料韧性,而且聚乙烯的介电性能和机械强度与其结晶形态密切相关.

Dielectric Properties and Mechanical Strength in Low-Density Polyethylene Modified by Metallocene Catalyzed Polyethylene

In order to increase the electrical breakdown strength and mechanical properties of polyethylene insulated power cable, a small amount of metallocene catalyzed polyethylene (MPE) is blended into low-density polyethylene (LDPE) in this paper. Then, the remnant space charges in the blends after pre-stressed and then short-circuit is measured by pulsed electro-acoustic (PEA) method. At the same time the volume resistivity, DC breakdown strength, breakdown voltage of opposite-polarity after DC pre-stress and mechanical strength in the blends are studied in detail. The test results show LDPE blended with 1 wt% MPE can effectively improve its breakdown strength and mechanical strength but reduce the volume resistivity and tenacity. It is also indicated that the dielectric property and mechanical strength in polyethylene are in close relation to its crystalline morphology.