聚丙烯/热塑性弹性体复合绝缘材料介电性能

Dielectric Properties of Polypropylene/thermoplastic Elastomer Composite Insulating Materials

聚丙烯(PP)具有高温热稳定、工作温度高和电气绝缘强等优势,还可实现回收再利用,有望成为未来电缆绝缘的替代材料,但PP的机械性能还需通过增韧改性以满足电缆敷设的需求。对此,主要研究以热塑性弹性体苯乙烯乙烯丁二烯苯乙烯嵌段共聚物(SEBS)与PP进行共混,制备了不同组分配比的PP/SEBS复合材料,进行红外光谱、差式扫描、电阻率、击穿电场强度、介电谱和结构表征测试。测试结果表明,随着SEBS含量的增加,结晶度、直流体积电阻率和直流击穿电场强度均下降,介质损耗因子上升;形貌观察表明,随着SEBS含量的增加,SEBS在PP中的分散性变差,球晶边界也逐渐模糊,与结晶度下降现象一致。综合来说,PP与SEBS质量之比为60∶40的PP/SEBS具有较高的直流体积电阻率和直流击穿电场强度,质量之比为70∶30的PP/SEBS具有较低的介质损耗因子,可用于指导未来PP电缆绝缘材料的配比优化。

Polypropylene(PP)has the advantages of high thermal stability,high working temperature and strong electrical insulation,and can also be recycled and reused,which is expected to become an alternative material for cable insulation in the future.But the mechanical properties of PP need to be toughened to meet the needs of cable laying.Therefore,this paper studies the blends of thermoplastic elastomer hydrogenated styrene-butadiene-styrene block copolymer(SEBS)with polypropylene.PP/SEBS composite materials with different mass fraction are prepared for the infrared spectroscopy,differential scanning,resistivity,breakdown field strength,dielectric spectrum,and structural characterization tests.The test results show that with the increase of SEBS content,the crystallinity,DC volume resistivity and DC breakdown field strength all decrease,the dielectric loss factor increases.The morphology observations indicate that with the increase of SEBS content,the dispersity of SEBS in PP got worse,and the boundnary of spherocrystal got more indistinct,consistent with the decrease of crystallinity.In general,the PP/SEBS ratio of 60/40 has the higher DC resistivity and DC breakdown field strength,and the PP/SEBS ratio of 70/30 has a lower dielectric loss factor.The conclusions can be used for guiding the optimized ratio of polypropylene cable insulation materials in the future.