纳米ZnO和纳米MMT对低密度聚乙烯介电性能的影响

分别采用添加纳米ZnO和纳米蒙脱土(MMT)粒子的方法提高低密度聚乙烯(LDPE)的介电性能,选择偶联剂对纳米粒子进行表面修饰,并利用熔融共混法制备了纳米ZnO/LDPE和纳米MMT/LDPE复合材料,通过XRD、FTIR和DSC对试样进行表征。研究了复合材料的交流击穿特性,对试样进行了空间电荷试验。结果表明:通过偶联剂修饰,纳米粒子与聚合物之间的界面结合得到改善,且纳米粒子在基体中的分散性更好;同时复合材料的结晶速率提高,结晶结构更完善;添加纳米粒子可以不同程度地提高LDPE的击穿场强,当纳米ZnO和纳米MMT的质量分数均为3wt%时,复合材料的击穿场强达到最大,分别比纯LDPE的击穿场强高出11.0%和10.3%;纳米ZnO和纳米MMT都有抑制空间电荷的作用,且ZnO的抑制效果更明显。

Effects of nano-ZnO and nano-montmorillonte on dielectric properties of low density polyethylene

Nano-ZnO and nano-montmorillonite (MMT) particles were added to improve the dielectric performance of low density polyethylene (LDPE). And the coupling agent was used in surface modification of nanoparticles. The composites of nano-ZnO/LDPE and nano-MMT/LDPE were prepared by melt blending method. The sample was characterized by XRD, FTIR and DSC. The alternating current breakdown properties of composites were investigated. The space charge tests were performed for the sample. Results show that the interface binding between nano-particles modified by coupling agent and polymer is improved, and the dispersion of nano-particles in matrix is more uniform, the crystallization rate of composites increases and crystalline structure becomes more perfect. Adding nanoparticles can increase the breakdown field strength of LDPE in different degrees. When the mass fraction of nano-ZnO and nano-MMT is 3wt%, respectively, the breakdown field strength of composites appear the highest values, which are 11.0% and 10.3% higher than those of origin LDPE, respectively. Both nano-ZnO and nano-MMT play an important role in inhibiting space charge, and the effect of nano-ZnO seems more obvious.