摘要
利用一种新型纳米材料碳纳米纤维(carbon nanofiber,CNF)对高密度聚乙烯(high-density polyethylene,HDPE)和高密度聚乙烯/超高分子量聚乙烯(ultra-high molecular weight polyethylene,UHMWPE)共混物(UHHDPE)进行改性,制备两相CNF/HDPE复合材料和三相CNF/UH-HDPE复合材料,研究CNF含量及其在基体中的分布状态对复合材料介电性能的影响。结果表明:CNF可良好分散于HDPE基体中,但无法渗入UHMWPE基体;CNF在两相复合材料中呈均匀分布状态,而在三相复合材料中呈非均匀分布状态;复合材料的介电常数随CNF含量增加而提高,当CNF质量分数达到7.5%以上时,CNF/HDPE复合材料在100 Hz下的介电常数达到190,比HDPE提高约50倍,且表现出明显频率依赖性;CNF/UH-HDPE复合材料的介电常数变化趋势与CNF/HDPE复合材料相同,但是在CNF含量相同时,三相复合材料的介电常数高于两相复合材料;当CNF含量较低时,两相和三相复合材料均无明显的介电损耗。
An attractive type of nanofiller-carbon nanofiber(CNF) was used to modify High-density Polyethylene(HDPE) and polymer blends(UH-HDPE) of HDPE and ultra-high molecular weight polyethylene(UHMWPE), and two-phase and three-phase nanocomposites were prepared via a two-step process including melt mixing and hot press. The effects of CNF addition and their dispersion on the dielectric properties of nanocomposites were investigated. The results show that CNFs are well dispersed in HDPE matrix, while they are not permeated into the UHMWPE. It is demonstrated that CNFs are distributed homogenously in two-phase CNF/HDPE composites and heterogeneously in three-phase CNF/UH-HDPE composites. The dielectric constant of nanocomposites is dramatically improved with higher CNF content. The highest dielectric constant in CNF/HDPE composites, 190 at 102 Hz, is achieved with CNFs above 10%(mass fraction, the same as below), which is about 50 times higher than that of pure HDPE.Simultaneously, the dielectric constant of CNF/HDPE composites shows high dependence on the frequency due to the existence of CNFs, compared with the independent dielectric constant of pure HDPE. The influence of CNFs on the dielectric constant of CNF/UH-HDPE composites is similar to that of CNF/HDPE composites. However, the dielectric constant of three-phase composites is higher than that of two-phase counterparts with the same CNF addition. Additionally, no obvious dielectric loss is exhibited in both nanocomposites with CNF concentration under 5%.
作者
孙莉莉
吴南
彭睿
SUN Lili;WU Nan;PENG Rui(AEEC Beijing Institute of Aeronautics Materials,Beijing 100095,China)
出处
《航空材料学报》
EI
CAS
CSCD
北大核心
2020年第4期109-115,共7页
Journal of Aeronautical Materials
