【摘要】 为研究低密度聚乙烯和掺杂浮石粉的聚乙烯中的空间电荷分布规律,采用热共混法制备了掺杂不同质量分数浮石粉的低密度聚乙烯(LDPE)材料,并利用脉冲电声法,分别测试了在不同电场强度下以及短路状态下的空间电荷分布随时间的变化。得出在电场的作用下,纯聚乙烯中的空间电荷主要积聚在电极附近且大部分为同极性电荷;相对地,浮石粉复合聚乙烯中则有大量的异极性电荷在阴极附近出现,并且电荷量随着浮石粉质量分数的提高而增加,而当浮石粉质量分数为5%时,且电场强度较高时,有大量正电荷从阳极注入并向阴极移动的空间电荷包现象;短路实验的结果表明,纯聚乙烯和浮石粉的质量分数为1%的复合聚乙烯中的空间电荷衰减较快,然而浮石粉质量分数为2%和5%的复合聚乙烯中的空间电荷衰减较慢。测试结果表明,浮石粉复合低密度聚乙烯材料中出现的异极性电荷和正电荷注入将有助于改善空间电荷分布,从而提高高聚物材料的介电性能。更多还原

【Abstract】 In order to find the discipline of space charge distribution in low-density Polyethylene (LDPE)/Pumice composites,composites with different pumice weight percentage (1%,2% and 5%) were prepared by melt blending process in torque rheometer.Space charge distribution in composites and pure LDPE were investigated with the pulsed electro-acoustic method (PEA).The results indicate that most of the space charge in pure LDPE under high electric field is homo-polarity space charge and gathers near both sides of the two electrodes.Oppositely,there is a great amount of hetero-polarity space charge appeared near cathode in LDPE/pumice composites.Meanwhile,the quantity of hetero-polarity space charge increases with the increasing of pumice content.A great amount of positive charge is injected in LDPE/Pumice composite with pumice 5% near the anode side and moves toward to the cathode of the sample when the electric field strength increases to 30 kV/mm and 50 kV/mm.As the circuit is shorted,the space charge in pure LDPE and LDPE/Pumice composite with pumice 1% decays rapidly,nevertheless,the space charge in LDPE/Pumice composite with pumice 2% and 5% decays more slowly.The results show that the hetero-polarity space charge which appears in the LDPE/Pumice composite and the positive charge is injected in LDPE/Pumice can contribute to improving the space charge distribution in LDPE and increasing the dielectric properties of polymer materials.更多还原