Ni@C/HDPE复合材料的制备及其正温度系数性能研究

PREPARATION OF Ni@ C/HDPE CONDUCTIVE COMPOSITES AND THEIR POSITIVE TEMPERATURE COEFFICIENT PERFORMANCE

采用还原气氛喷雾燃烧法制备了具有核壳结构Ni@C纳米复合颗粒,并与HDPE共混挤出制备了聚合物基PTC导电复合材料,并且对其结构和性能进行了表征.结果表明,所制备的Ni@C复合纳米颗粒具有典型的核壳结构,其中,金属镍的核的粒径为30~50 nm,碳包覆壳层的厚度约为2.9 nm,热重分析结果表明Ni@C复合纳米颗粒的含碳量为3.4%,碳包覆层的存在阻止了金属镍颗粒的团聚;对Ni@C/HDPE复合材料的断面SEM和切片TEM分析结果表明复合颗粒在HDPE基体中分散性良好,复合材料的渗流阈值为10wt%,PTC强度为8个数量级.

Carbon encapsulated nickel（Ni@ C） nanoparticles were synthesized via one step reducing flame spray pyrolysis approach and mixed with HDPE to prepare polymer based positive temperature coefficient（PTC） conductive composites.The as-prepared Ni@ C nanoparticles possessed a core/shell structure with carbon shell located outside and nickel core located inside.The mean size of Ni@ C nanoparticles was 30 ~ 50 nm,and the carbon shell was about 2.9 nm in thickness.The carbon content of Ni @ C was about 3.4% calculated from TG analysis.The existence of carbon shell has significantly prevented the agglomeration of metallic nickel particles.Investigations of composite structure were carried by using an optical microscope on slides of composites and section SEM analysis.Results showed the Ni@ C had a good spatial distribution in the HDPE matrix,and the PTC conductive composite performed a low percolation threshold of 10 wt% and a high PTC intensity of 8 in magnitude.