超高相对分子质量纤维素对Lyocell纺丝性能的影响

在常规相对分子质量的纤维素(DP=722)中加入少量超高相对分子质量的纤维素(DP≈10 000)并以此为原料,以N-甲基吗啉-N-氧化物(NMMO)水溶液为溶剂,采用Lyocell工艺进行纺丝。结果发现:添加超高相对分子质量的纤维素并未能有效地提高所得纤维的强度和模量。对纺丝过程中不同位置纺丝原液的流变性能和纤维素相对分子质量及其分布进行分析,结果进一步表明超高相对分子质量纤维素的添加,虽能得到溶解均匀的纺丝原液,但该纺丝原液在纺丝压力下通过过滤层及组件时易产生流动性分层现象,导致所得Lyocell纤维的力学性能无明显改善。

Effect of super-high molecular weight cellulose on the spinning properties of Lyocell

The cellulose material formed by mixing general molecular weight pulp(DP=722) with a small quantity of super-high molecular weight pulp(DP≈10 000) was dissolved in N-methylmorpholine-N-oxide monohydrate(NMMO.H2O) and the resultant dope was spun by Lyocell process.It was found that the addition of super-high molecular weight cellulose did not enhance the strength and modulus of Lyocell fiber effectively.Combined with the analysis of the rheological properties of the dopes taken from different positions during spinning process,and the molecular weight and its distribution of cellulose in the dopes,it was clear that the addition of the super-high molecular weight cellulose resulted in dope separation when it flew through filter under the spinning pressure and therefore the mechanical properties of prepared Lyocell fiber could not be improved obviously.