纤维素浆粕和Lyocell纤维在LiCl/DMAc中溶解差异的研究

为了研究Lyocell工艺中纤维素相对分子质量分布的变化,分析了纤维素浆粕和相应的由浆粕生产出的Lyocell纤维在LiCl/DMAc中的溶解情况,发现两者存在很大差异,分别从纤维素的晶型、取向和形态结构等方面分析原因。结果表明:由于Lyocell纤维(纤维素II)比纤维素浆粕(纤维素I)在热力学上更稳定,分子间的氢键更多,且Lyocell纤维的取向较纤维素浆粕高,纤维结构较致密,使得溶剂的渗透和氢键的破坏更加困难,因此Lyocell纤维在LiCl/DMAc中的溶解比纤维素浆粕差。

Study on the Dissolution Difference of Linter Pulp and Lyocell Fiber in LiCl/N,N-dimethylacetamide

The dissolutions of linter pulps and the corresponding Lyocell fibers in LiCl/N,N-dimethylacetamide(DMAc) were studied to analyze the change of molecular weight distribution of cellulose during Lyocell process. The results showed that remarkable differences in the dissolutions between pulps and Lyocell fibers were observed. And the reasons were analyzed from the viewpoints of crystalline structure, orientation and morphology. Lyocell fibers(cellulose II) were more stable than linter pulps(cellulose I) in thermodynamics, and more intermolecular hydrogen bondings existed in Lyocell fibers. Moreover, Lyocell fibers had higher orientation and compacter structure than pulp. Therefore, the permeation of solvent and breakage of hydrogen bondings were more difficult for Lyocell fibers. The dissolution of Lyocell fiber in LiCl/ DMAc was worse than that of cellulose pulp.