一步法合成高T_g可溶含偶氮三嗪发色团的新型侧链含氟聚酰亚胺

采用一步法合成了一系列侧链含偶氮三嗪发色团的新型含氟聚酰亚胺FPI(x),并研究其溶解性能、热性能以及光学性能.该系列聚酰亚胺具有优良的溶解性能,不仅溶于NMP,DMAc,DMF,DMSO等强极性非质子性溶剂,而且还溶于THF和乙二醇单甲醚等低沸点溶剂.FPI(x)系列共聚聚酰亚胺具有较高的玻璃化转变温度(T_g,在544～562K之间),且与主链中染料发色团的含量无关.所有聚酰亚胺都表现出优良的高温稳定性,其5%热失重温度(T₅)比T_g高出100K以上,基本能满足电场极化对聚合物材料热稳定性的要求.另外,FPI(x)系列聚酰亚胺的紫外截止吸收波长小于500nm,即在大于500nm波长范围内基本透明.其面内折光指数n_TE随着染料发色团含量的增加而逐渐增加.

One-step Synthesis of High Tg Organo-soluble Side-chain Fluorinated Polyimides Containing a Triazine-azo Chromophore

A series of fluorinated copolyimides containing a triazine azo chromophore were prepared by a one step method. The copolyimides obtained were characterized by FTIR spectra, UV Vis spectra, DSC, TGA and the prism coupling device. The copolyimides are soluble not only in aprotic organic solvents such as N methyl 2 pyrrolidone(NMP), N,N dimethyl acetamide(DMAc), N,N dimethyl formamide(DMF), dimethylsulfoxide(DMSO), but also in low boiling point solvents such as ethyleneglycol monomethyl ether and tetrahydrofuran(THF). They are almost completely transparent at wavelengths greater than 500 nm. All copolyimides possess high glass transition temperatures( T g, 544-562 K) and are almost independent of the chromophore loading level. The 5% weight loss temperatures( T 5) of the copolyimides are more than 100 K higher than the corresponding T gs and this high thermal stability would ensure high temperature electric poling of the copolyimides. The in plane refractive index of a copolyimide is increased as the chromophore content is increased.