含氟及硫醚基团聚酰亚胺光波导材料的合成及表征

通过分子设计,合成了含三氟甲基及硫醚基团的二胺单体4,4'-双(4-胺基-2-三氟甲基苯硫基)二苯硫醚(6FSEDA),利用其与6种芳香二酐单体:3,3',4,4'-联苯四羧酸二酐(BPDA)、4,4'-氧双邻苯二甲酸酐(ODPA)、3,3',4,4'-二苯酮四酸二酐(BTDA)、4,4'-(六氟异丙基)-苯二酸酐(6FDA)、3,3',4,4'-二苯硫醚四酸二酐(DTDA)及3,3',4,4'-二苯砜四酸二酐(DSDA)经一步法合成了一系列含氟及硫醚基团的聚酰亚胺(PI),并对其结构与性能进行了研究.结果表明,该系列PI的玻璃化温度Tg(DSC)在199.8～231.7℃范围,5%和10%热失重的温度(N2氛围)分别在491℃和517℃以上,在400～700 nm的可见光波长范围内具有优异的光学透明性,在光通讯波段(1310 nm和1550 nm处)均无明显吸收,且在这两个波长处测得的平均折射率范围分别为1.5401～1.6142和1.5389～1.6124,在波长632.8 nm测得的双折射范围为0.0012～0.0045.可见,含氟及硫醚基团聚酰亚胺薄膜具有良好的热稳定性和光学性能.

SYNTHESIS AND CHARACTERIZATION OF POLYIMIDES CONTAINING FLUORINE AND THIOETHER GROUPS AS WAVEGUIDE MATERIALS

A novel aromatic diamine containing fluorine and thioether groups,4,4′-bis(4-amino-2-(trifluoromethyl)phenylsulfanyl)diphenyl sulfide(6FSDEA),was synthesized by the condensation and reduction reaction with 1-chloro-4-nitro-2-(trifluoromethyl)benzene and 4,4′-thiobisbenzenethiol as starting material.Then it was polymerized with six various dianhydrides,including BPDA,ODPA,BTDA,6FDA,DSDA and DTDA via one-pot polycondensation to produce a series of novel polyimides.The polyimides are soluble in conventional polar organic solvents,such as NMP,DMF,DMAc,m-cresol,and some of them are even soluble in CDCl3 and acetone.The glass transition temperatures of plyimides were in the range of 197.1~235.1℃(DMA) and 199.8~231.7℃(DSC),respectively.Moreover in nitrogen atmosphere the 5% and 10% weight loss temperatures were in the range of 491~535℃ and 517~557℃,respectively.And the char yields at 800℃ were between 30 wt%~63 wt%.In addition,the PI films showed good optical transparency in the visible light region(400~700 nm) with the cutoff wavelengths range of 380~417 nm,and little absorption at the optical communication wavelengths of 1310 nm and 1550 nm.Furthermore,the average refractive indices(nAV) of the polyimide films at 1310 nm and 1550 nm were 1.5401~1.6142 and 1.5389~1.6124 respectively,measured by using a Variable Angle Spectroscopic Ellipsometer.The birefringence(Δn) of the polyimide films at 632.8 nm were in the range of 0.0012~0.0043 obtained by the prism coupling device.The above results showed that these PIs could be used as candidates for optical waveguide materials.