耐高温聚间苯二甲酰间苯二胺介电复合材料的制备及性能

Preparation and Properties of High-temperature Poly(metaphenylene isophthalamide)Dielectric Composites

采用水热法以二氧化钛(TiO_(2))纳米粒子为原料合成了高长径比钛酸钡纳米线((BaTiO_(3)nanowires(BTN));为了改善BTN与聚合物基体的相容性并保持BTN完整的化学结构,选择聚乙烯吡咯烷酮(PVP)作为改性剂,通过物理吸附作用将其包裹在BTN表面形成P-BTN纳米线;随后将P-BTN作为高介电常数填料加入到聚间苯二甲酰间苯二胺(PMIA)基体中制备出耐高温的PMIA介电复合材料。研究了P-BTN含量对PMIA复合材料介电性能、击穿强度的影响以及高温下P-BTN/PMIA复合材料介电性能的变化。结果表明:BTN经过PVP表面改性后,在P-BTN含量较高时依然可以均匀地分散在PMIA基体中,且与PMIA基体具有良好的相容性;随着P-BTN含量的增加,PMIA复合材料的介电常数提升明显;100 Hz时,含有15%(质量分数)P-BTN的PMIA复合材料的介电常数提升至18.5,相较于纯PMIA增加了7.4倍,同时介电损耗依然较低;在高温环境中(150~250℃),P-BTN/PMIA复合材料的介电性能稳定,没有出现明显波动,满足高温环境对材料介电性能的使用要求;此外,低含量P-BTN还可以改善PMIA介电复合材料的击穿强度,适用于更高电场强度环境中。

Barium titanate nanowires(BTN)with high aspect ratio were synthesized through a hydrothermal method by using titanium dioxide(TiO_(2))nanoparticles.In order to improve the compatibility between BTN and polymer matrix as well as maintain the completely chemical structure of BTN,Polyvinylpyrrolidone(PVP)was selected as modification that was wrapped on the surface of BTN by physical adsorption and the modified BTN nanowires were named as P-BTN.Subsequently,P-BTN were added into poly(metaphenylene isophthalamide)(PMIA)matrix to prepare PMIA dielectric composite.The dielectric property and breakdown strength of P-BTN/PMIA composite were investigated by varying the content of P-BTN nanoparticles;furthermore,effect of high temperature on dielectric properties of P-BTN/PMIA composites was also researched.The obtained consequences indicate that,due to effective modification of PVP on BTN,the prepared P-BTN are homogeneously dispersed in PMIA matrix even at relatively high P-BTN content,and the compatibility between BTN and PMIA matrix improves as well.With increasing content of P-BTN,the dielectric constant of P-BTN/PMIA composites obviously increases.For example,the dielectric constant of PMIA composite with 15wt%P-BTN increases to 18.5,which is 7.4 times that of pure PMIA,and the dielectric loss keeps at low value.It is worth noting that,even at high temperature(150—250℃),the dielectric properties of prepared P-BTN/PMIA composites are still stable,which can meet the requirements of high temperature for dielectric composites.In addition,the breakdown strength of PMIA composite can be enhanced at low content of P-BTN nanoparticles,which is suitable for application under highly electric field.