In this paper,3,3-d1aminobenzidine (DABz) and 4,4-dicarboxydiphenyl ether (DCDPE) were used as raw materials by nucleophilic polycondensation to prepare polybenzimidazole (PBI).PBI polymer has a long main chain with ether bond structure which has good solubility and can be dissolved in a variety of solvents,such as DMAc,DMF,MSA,NMP,DMSO,etc.Chemical structure of PBI was confirmed by means of nuclear magnetic resonance (1HNMR) and infrared spectroscopy (FTIR).And then a series of PBI porous membrane with pore structure were prepared in constant temperature and humidity chamber by water vapor induced method in order to explore the optimum conditions for the formation of spongy pores.The morphology of porous membranes was observed by scanning electron microscopy (SEM).The effects of solvent,film forming time,temperature,relative humidity and polymer concentration on the membrane structure were investigated in detail,and the result shows:at 80 ℃ and 60％ relative humidity,by using MSA as solvent,cavity wrapped pores was appeared,spongy pore structure was appeared by using DMAc and DMF as solvent,however,DMSO and NMP still make the PBI film maintain a dense membrane structure.When DMAc are used as solvent,film-forming time should not be less than 10 min;and humidity should not be less than 50％.The membrane surface and cross section pore diameter decreases with the increase of polymer concentration,and the bottom surface becomes denser.Membrane surface and cross section pore diameter decreases with the increase of the humidity at the same temperature;membrane surface and cross section diameter decreases with the increase of temperature under the same relative humidity.%以3,3′-二氨基联苯胺和4,4 ′-二羧基二苯醚为原料,通过亲核缩聚合成了分子主链上带有醚键结构且具备较好溶解性的聚苯并咪唑,通过核磁共振和红外光谱确定其化学结构.接着利用水蒸汽诱导相分离法制备了系列具有海绵状孔结构的多孔膜,用扫描电子显微镜观察其形貌结构.详细考察了溶剂种类、成膜时间、温度、湿度以及聚合物溶液浓度等因素对膜结构的影响.结果表明,在温度80℃、相对湿度60％时,以甲磺酸为溶剂可使聚苯并咪唑膜出现腔包状孔结构;以N,N-二甲基甲酰胺和N,N-二甲基乙酰胺为溶剂可使聚苯并咪唑膜出现海绵状孔结构;而二甲基亚砜、N-甲基吡咯烷酮这两种溶剂不能使其出现多孔结构.以N,N-二甲基乙酰胺为溶剂时,聚苯并咪唑膜出现海绵状孔结构的成膜时间应不小于10 min,成膜湿度应不小于50％,膜表面和断面孔径随着聚合物溶液浓度的增加而减小,底面也越来越致密.温度一定时,膜表面和断面孔径随着湿度的增加而减小;湿度一定时,膜表面和断面孔径随着温度的增加而减小.
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