聚丙烯腈原液凝固成型工艺对原丝结构的影响

Effects of Polyacrylonitrile Fluid Solidification Process on Structure of Precursor

研究了聚丙烯腈(PAN)纺丝原液在凝固浴中的相分离路径和结构变化机理,探索形成结构致密原丝的延时分相路径,并分析不同工艺对原丝形态结构的影响。结果表明:提高凝固浴浓度、降低凝固浴温度、提高原液初始浓度有利于形成微孔尺寸较小的致密结构,并提高原丝的强度、模量等性能指标;延长原液细流在凝固浴中的停留时间,可使原丝外层和芯层的结构差异减小,强度不匀率等有较大幅度的下降;提高原液初始浓度有利于缩小原丝微孔尺寸,但原丝的强度不匀率等离散性指标上升;提高原液温度可以降低强度等不匀率值;提高原液中溶剂(Na SCN)质量分数,原丝微孔尺寸变小,原丝的沸水收缩率、长度和纤度不匀率均明显下降。

The phase separation path and structure changing mechanism of polyacrylonitrile （PAN） spinning solution in coagulation bath were studied, the delay phase path forming precursor with dense structure was explored, and the effects of different processes on morphological structure of precursor were analyzed. Result showed that raising and reducing temperature of coagulation bath, and raising initial concentration of solution were favorable for forming dense structure with little - size micropores, and meanwhile the intensity and modulus of precursor could be raised; expanding the detention time of solution trickle in coagulation bath could narrow the structure difference between outer layer and core layer of precursor, and remarkably reduce the strength unevenness rate; raising original concentration of solution was favorable for reducing size of micropores of precursor, but might cause raising of indicators of divergence as strength unevenness of precursor; raising solution temperature could reduce the unevenness rates as strength; increasing mass fraction of dissolvent of solution （NaSCN） ould reduce the size of micropores of precursor, as well as the boiling water shrinkage, and unevenness of length and fine degree of precursor.