PVDF-HDPE双相PTC材料的制备、结构与性能

Preparation,Structures and Properties of PVDF-HDPE Bi-phase PTC Materials

分别以聚偏氟乙烯(PVDF)、高密度聚乙烯(HDPE)为基体,炭黑(CB)为导电填料,采用两步熔融混合法,制备了PVDF-HDPE-CB导电复合材料。通过差示扫描量热(DSC)、溶剂抽提、扫描电子显微镜(SEM)等方法表征了复合材料的结构,采用电阻测试仪等仪器测试了复合材料的性能。研究了PVDF与HDPE体积比与复合材料结构的关系,以及对复合材料导电性、正温度系数(PTC)特性、耐电压性能的影响。结果表明,复合材料具有双相PTC材料结构,在复合材料中,HDPE易形成连续相,少量添加即可显著提高以PVDF为基体的PTC材料的导电性和耐电压性能。

Nanocolorants were prepared by miniemulsion polymerization with sodiumα-olefin sulfonate（AOS）as polymerizable emulsifier,styrene（St）as monomer,methyl methacrylate（MMA）as polar monomer,divinylbenzene（DVB）as crosslinking agent,hexadecane（HD）as co-stabilizer.Transmission Electron Microscopy（TEM）and Dynamic Laser Light Scattering（DLS）were used to study the effects of the amount of AOS,polar monomer and crosslinker on the morphology of nanocolorants.Results showed that the average particle size of nanocolorants decreased with the increasing of the amount of AOS.Appropriate amount of polar monomer was helpful to produce the core-shell particles with narrow particle size distribution.The difference of polarity between monomer and crosslinker led to the rough surface of nanocolorants.When St was used as monomer,the nanocolorants appeared crumpled surface as the mass of DVB relative to St was higher than 30%.However,for MMA,the nanocolorants appeared serious crumpled surface when the mass of DVB relative to MMA was in the range of 8%—30%.