碳纳米管添加剂对Lyocell纺丝原液流变行为及其纤维结构与性能的影响

Effect of the Multi-Wall Carbon Nanotubes(MWNTs) on the Rheological Behavior of Cellulose/NMMO·H_2O Solution and Structure and Properties of Lyocell Fibers

制备了添加不同质量分数多壁碳纳米管(MWNTs)的Lyocell纺丝原液,对其流变性能进行了研究,并通过干湿法纺丝得到MWNTs填充的Lyocell纤维,分别采用扫描电镜(SEM)和强度仪等对纤维的形态结构与力学性能进行了分析.研究结果表明,添加了MWNTs的纤维素/NMMO.H2O溶液属典型的切力变稀型流体.随着溶液中MWNTs添加量的增加,溶液粘度逐渐增大.在MWNTs质量分数达到1%时,体系粘度呈现出最大值,但随着MWNTs质量分数的进一步增加,体系的粘度又出现明显的下降趋势.对所制得的MWNTs/Lyocell复合纤维的SEM分析结果显示:当MWNTs质量分数≤1%时,MWNTs在Lyocell基体中分布均匀;当MWNTs质量分数>1%时,复合纤维中MWNTs开始发生团聚.对纤维的力学性能分析进一步表明:添加适量的MWNTs可使Lyocell纤维的力学性能提高,其中,1%MWNTs质量分数的Lyocell纤维的初始模量和强度分别比未添加MWNTs的Lyocell增加32.9%和18.8%.

Cellulose/NMMO·H2O spinning solutions filled with various amounts of MWNTs were prepared, and the rheological properties of these dopes were studied. Then the Lyocell fibers filled with MWNTs were prepared by dry-wet spinning, and the morphological structure and mechanical properties of these samples were investigated by SEM and tensile strength tester, respectively. The results showed that the cellulose/NMMO ·H2O solution filled with MWNTs belongs to the typical shear thinning fluid. The viscosity of the solution increased firstly with the addition of MWNTs and reached the highest value with 1% MWNTs, then decreased obviously with the further addition of MWNTs. The SEM results for the MWNTs/Lyocell fibers showed the MWNTs were dispersed uniformly in the Lyocell matrix when the addition of MWNTs was equal or less than 1 %. The addition of appropriate amount of MWNTs could improve the mechanical properties of composite fiber. Compared with the general Lyocell fiber, the modulus and tenacity of the composite fibers containing 1% MWNTs were increased by 32. 9% and 18. 8M, respectively.