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.