Formation of the crystal structure of Lyocell fiber during drying 2nd ICC 2007, Tokyo, Japan, October 25–29, 2007

Abstract

Abstract Lyocell fiber, a new type of regenerated cellulose fiber, is produced by an environmentally friendly dry-wet spinning process without hazardous byproducts. In order to prepare high performance Lyocell fiber, the formation of crystal structure of never dried (n.d.) Lyocell fiber and the difference of crystal structures between n.d. Lyocell fiber and rewetted Lyocell fiber was investigated by wide angle X-ray diffractometry. The results showed that the supramolecular order of n.d. Lyocell fiber with high water content was not fully developed and, accordingly, the paracrystalline moiety of the of fibers was very high. The crystallinity and lateral order increased with the decreasing water content. When water content of n.d. Lyocell fiber was less than 35%, most paracrystalline structures in the fiber turned into crystalline structures. On the other hand, it was found that once the crystal structure of Lyocell fiber was formed, it could not be destroyed by rewetting. This finding indicates that only the crystal structure of Lyocell fiber could be changed. By heat treatment of n.d. Lyocell fiber, the mechanical properties of the fiber were improved effectively.