【摘要】 通过原位缩聚,采用3,3′,4,4′-联苯四羧酸二酐(BPDA)和4,4′-二氨基二苯醚(ODA)为主要原料制备了聚酰亚胺(PI)复合管膜。首先合成聚酰胺酸(PAA),并旋涂制备了聚酰胺酸管膜,然后将溶有碳粉的氟树脂与纯聚酰胺酸管膜复合并热亚胺化,最后再涂覆保护层,制得PI复合管膜。采用傅里叶红外光谱仪(FT-IR)、差式扫描量热法(DSC)、热重分析(TGA)、精密阻抗分析仪和高阻计分别对聚酰亚胺复合管膜的结构、玻璃化转变温度(Tg)、分解温度(Td)、介电性和电阻率进行了表征。研究结果表明,聚酰亚胺管膜的Tg为312.5℃,失重5%的分解温度为560℃。PI复合管膜的介电常数较纯PI管膜稍有增加,碳粉层的加入有效改善了纯PI管膜的介电常数随频率的突变行为,而介质损耗方面,PI复合管膜比纯PI管膜稍有降低。PI复合管膜的表面电阻率比纯PI管膜降低了92.85%,体积电阻率比纯PI管膜降低了77.30%。更多还原

【Abstract】 A kind of biphenyl polyimide composite tubular film was prepared.First,polyamic acid(PAA) was synthesized by in-situ polycondensation using 3,3’,4,4’-biphenyltetracarboxylic dianhydride acid(BPDA) and 4,4’-oxydianiline(ODA) as main materials,and composite PAA tubular film was prepared by spin coating,and then fluroresin with carbon powder was overlaid on PAA film and imidized.Lastly,fluroresin was coated as a surface layer.The chemical structure,glass transition temperature(Tg),decomposition temperature(Td),dielectric performance and electrical resistivity of the obtained film were characterized by Fourier transform infrared spectroscopy(FT-IR),differential scanning calorimetry(DSC),thermogravimetric analysis(TGA),precision impedance analyzer and megohmmeter,respectively.The results show that the Tg of PI tubular film is 312.5 ℃,the Td with 5% loss is 560 ℃.With adding of carbon powder,dielectric constant of PI composite film is reduced,the wave of dielectric constant versus frequency is effectively improved,while the dielectric loss reduced,surface resistivity decreased by 92.85% and volume resistivity 77.30%.更多还原