改性纳米氧化镁交联聚乙烯复合材料的制备及其电气性能研究

Study on preparation and electrical properties of modified nano magnesia⁃crosslinked polyethylene composites

为提高交联聚乙烯(PE-XL)绝缘性能,以聚乙烯(PE)为基体,以改性后的MgO(MgO-NH_(2))为填料进行复配交联制备了PE-XL/MgO-NH_(2)纳米复合材料,对其热老化前后的电绝缘性能进行了研究,并与未改性的MgO交联聚乙烯复合材料(PE-XL/MgO)进行了对比研究。通过直流击穿强度、空间电荷和直流电导率来研究复合材料的绝缘性能。与未老化PE-XL/MgO相比,未老化PE-XL/MgO-NH_(2)纳米复合材料的直流击穿强度提高了20%,异质空间电荷积累可以忽略不计。热老化后,PE-XL/MgO和PE-XL/MgO-NH_(2)纳米复合材料的直流击穿强度分别较热老化前降低了38%和20%。此外,将MgO表面改性后制备的PE-XL/MgO-NH_(2)纳米复合材料比PE-XL/MgO具有更低的直流电导率。PE-XL/MgO-NH_(2)纳米复合材料在未老化条件下表现出较好的性能,且对热老化可能引起的劣化表现出更强的抑制作用。

To improve the insulation performance of crosslinked polyethylene(PE-XL),MgO-NH_(2)/PE-XL nanocompos-ites were prepared by using polyethylene(PE)as a matrix and modified MgO(MgO-NH_(2))as a filler.The electrical in-sulation performance of the nanocomposites before and after thermal aging was investigated.The obtained results were compared with the unmodified MgO-crosslinked polyethylene composites(PE-XL/MgO).The insulation properties of the nanocomposites were studied by DC breakdown strength,space charge,and DC conductivity.Compared to the non-aged PE-XL/MgO,the non-aged PE-XL/MgO-NH_(2) nanocomposites showed an increase in DC breakdown strength by 20%,and the heterogeneous space charge accumulation could be negligible.After thermal aging,the breakdown strength of MgO/PE-XL and PE-XL/MgO-NH_(2) nanocomposites decreased by 38%and 20%,respectively,compared to those before thermal aging.In addition,the PE-XL/MgO-NH_(2) nanocomposites obtained from the surface modifica-tion of MgO have a lower DC conductivity than PE-XL/MgO.The PE-XL/MgO-NH_(2) nanocomposites exhibited better performance under non-aging conditions,and they also showed stronger inhibition to the deterioration caused by thermal aging.