凝固张力对聚丙烯腈初生纤维凝聚态的作用机理

Mechanism of Coagulation Tension on the Aggregation of Polyacrylonitrile Nascent Fibers

控制纺丝工艺中外场条件恒定,通过改变单因素凝固张力制备聚丙烯腈(PAN)初生纤维。运用X射线衍射、傅里叶变换红外、张力仪进行研究,探讨凝固张力对初生纤维凝聚态的影响,并分析其内在作用机理。结果表明,在凝固相分离过程中,凝固张力值影响着分子链构象状态和初生纤维的结晶性;随着凝固张力的增大,分子链螺旋构象成分逐渐增多,结晶度先降低后升高。外加凝固张力和内部分子链构象共同影响着初生纤维的结晶性。

The polyacrylonitrile( PAN) nascent fibers were prepared by changing coagulation tension with other coagulation process constant. Wide-angle X-ray diffraction( WAXD),Fourier transform infrared( FT-IR) and the tension test were carried out to examine the effect of the tension on the aggregation structure of nascent fibers and the mechanism was discussed. The results indicate that coagulation tension affects molecular chain conformation and the crystallinity.With increase of tension,molecular chains convert into helical conformation gradually and the crystallinity decreases at first and then increases. Coagulation tension and molecular chain conformation jointly are responsible for the crystallinity of the PAN nascent fibers.