干法纺丝聚(苯并咪唑-酰亚胺)纤维的制备及性能研究

Preparation and properties of poly( benzimidazole-co-imide) fibers via dry spinning process

以3,3',4,4'-联苯四甲酸二酐为二酐单体,对苯二胺和2-(4-氨基苯基)-5-氨基苯并咪唑为二胺单体,在非质子溶剂中合成前驱体聚酰胺酸,采用干法纺丝、热环化及热拉伸制备聚(苯并咪唑-酰亚胺)(简称聚酰亚胺)纤维(PI纤维),研究了不同拉伸倍数下的PI纤维的结构及性能。结果表明:PI纤维表面光滑致密,截面为肾形;随着拉伸倍数提高,PI纤维的取向度和力学性能提高;当拉伸倍数为6.35时,其取向因子为0.81,拉伸强度为2.31 GPa,拉伸模量达到117.0 GPa;随着拉伸倍数提高,PI纤维的玻璃化转变温度(T_g)逐渐降低,T_g为324~342℃;PI纤维在500℃以上开始热分解,具有良好的热稳定性能。

A poly（ amic acid） precursor was synthesized by using 2-（ 4-aminophenyl）-5-amino-benzimidazole as diamine monomer and 3,3＇,4,4＇-biphenyl tetracarboxylic diandhydride as dianhydride monomer in presence of aprotic solven and was produced into poly（ benzimidazole-co-imide）（ PI） fibers by dry spinning process,heat imidization and hot drawing. The structure and properties of PI fiber were studied at different draw ratios. The results showed that the obtained PI fiber had smooth and compact surface and kidney-shaped cross section; the degree of orientation and the mechanical properties of PI fiber were increased with the increase of draw ratio; the orientation factor,the tensile strength and the tensile modulus were 0. 81,2. 31 GPa and 117. 0 GPa,respectively,as the draw ratio was 6. 35; the glass transition temperature（ Tg） of PI fiber was gradually decreased to 324-342 ℃ with the increase of draw ratio; the thermal decomposition of the obtained PI fiber started above 500 ℃,indicating fairly good thermal stability.