不同玻璃化转变温度聚丙烯腈共混溶液的流变行为研究

Research on the rheological properties of different glass-transition temperature PAN copolymers blend spinning dope

将两种不同玻璃化转变温度丙烯腈共聚物A(常规PAN)与B(改性PAN)配置成新的纺丝原液(溶剂为NaSCN溶液),利用旋转流变仪研究了这种共混溶液的流变行为,结果表明:所得共混纺丝原液属于切力变稀流体,相对于常规聚丙烯腈原液,其粘度较大,并且随着B含量的增加,其出现凝胶的概率增加,凝胶点向低频方向移动,形成网络结构,体系弹性增加;这种共混纺丝原液具有较小的粘流活化能,粘度随温度的变化小,有利于纺丝成型。

Two acrylonitrile copolymers with different glass-transition temperature A（ conventional PAN） and B（ modified PAN） were blended,in different proportion to prepare special PAN spinning dopes. The rheological properties of obtained PAN（ AB）/sodium thiocyanate solution were studied using rotational rheometer. The results showed that this spinning dope belonged to a typical pseudoplastic fluid. Compared to the conventional spinning dopes,the viscosity of the blend spinning dopes was higher. With the increase of the B content,the blend spinning dopes were more likely to appear gel and gel point moves to lower shear rates. The network structure was formed and system flexibility was also improved. Besides,the flow-activation energy of blend spinning dope was lower than the conventional one,which meant less influence on spinning by temperature. Thus the stability of the blend spinning dopes was enhanced and it could benefit the spinning extrusion and forming.