摘要
以对苯二胺(PDA)、2,2′-双(三氟甲基)-4,4′-二氨基联苯(TFDB)、降莰烷-2-螺-α-环戊酮-α′-螺-2″-降莰烷-5,5″,6,6″-四甲酸二酐(CPODA)为原料制备了一系列含降冰片基的共聚低介电常数透明聚酰亚胺薄膜材料。采用傅里叶变换红外光谱、热重分析、热机械分析、介电测试、光学测试、力学性能测试研究了TFDB中三氟甲基对合成材料综合性能的影响,同时通过分子模拟技术分析了材料微观结构,解释了性能变化的内在机理。结果表明,合成的聚酰亚胺材料已经完全亚胺化;随着TFDB物质的量分数从0%增加到40%,热失重1%温度从453℃降低到432℃,在频率为105 Hz条件下,介电常数从2.87降低到2.68,介电损耗角正切从0.007 3降低到0.004 8,截止波长从372 nm降低至361 nm;合成的材料在450 nm处的透过率均达到了85%。TFDB引入使材料拉伸性能下降,所有材料均溶解于N,N-二甲基甲酰胺和N,N-二甲基乙酰胺。分子模拟结果表明,降冰片基团中不含有苯环,缺少苯环电子共轭,在三氟甲基吸电子作用和大体积效应下,单位体积的偶极矩和极化率降低,分子链间距增大,分子间的作用力减小,聚合物的内聚能密度随之降低,聚合物的自由体积分数增加。降冰片与三氟甲基的引入可使聚酰亚胺材料的介电常数降低、光学性能得到提升,可以通过调节TFDB的含量来平衡材料的综合性能。
Transparent polyimide films containing norborneol with low dielectric constant were prepared by incorporating 2,2′-bis(trifluoromethyl)benzidine(TFDB)into polymer backbones dispiro[4,7-methanoisobenzofuran-5(3H),1′-cyclopentane-3′,5″(3″H)-[4,7]methanoisobenzofuran]-1,1″,2′,3,3″(4H,4″H)-pentone,octahydro-(CPODA)/p-phenylenediamine(PDA).Fourier transform infrared spectrum,thermogravimetry,thermomechanical analysis,dielectric,optical and mechanical tests were carried out to investigate the effects of trifluoromethyl groups in TFDB on the comprehensive properties of the films.Molecular simulation was used to analyze the microstructures of the films and explain the internal mechanism of the performance variation.The results show that the imidization of the film is fully completed.When the mole fraction of TFDB increases from 0%to 40%,the 1%weight loss temperature decreases from 453℃to 432℃,the dielectric constant decreases from 2.87 to 2.68 and the tangent of dielectric loss angle decreases from 0.0073 to 0.0048 at a frequency of 105 Hz,the cutoff wavelength decreases from 372 nm to 361 nm.The transmittance of the films all reach 85%.The tensile properties of the film decrease due to the introduction of TFDB and the film can be dissolved in N,N-dimethylformamide and N,N-dimethylacetamide.The molecular simulation indicates that the absence of benzene ring in norborneol group leads to a lack of benzene ring electron conjugation.Both the dipole moment and polarizability per unit volume are decreased and the spacing between molecular chains is increased as a result of the electron absorption and large volume effect of trifluoromethyl.The intermolecular force reduces,and the cohesive energy density of the polymer declines simultaneously,the free volume fraction of the polymer increases.The introduction of norborneol and trifluoromethyl can decrease the dielectronic conatant and enhance the optical performance of the polyimide film and the comprehensive performances can be balanced by adjusting the TFDB content.
作者
黄安民
彭军
王进
杨海洋
Huang Anmin;Peng Jun;Wang Jin;Yang Haiyang(Zhuzhou Times New Material Technology Co.,Ltd.,Zhuzhou 412007,China)
出处
《工程塑料应用》
CAS
CSCD
北大核心
2023年第10期37-43,共7页
Engineering Plastics Application
关键词
低介电常数
透明性
聚酰亚胺
降冰片
分子模拟
low dielectric constant
transparency
polyimide
norborneol
molecular simulation
作者简介
通信作者:彭军,博士,研究方向为功能性高分子材料。
