Design of ionic solvents for production of man-made cellulose and silk fibers

Abstract

The making man-made fibers, mainly based on wood pulp, started since the late 19th century. Their industrial production, reaching a maximum in the middle of the twentieth century, was later gradually declining. Due to ecological restrictions the fiber industry began to use the new technology Lyocell instead of the viscose process. In this technology, to solve cellulose, hydrogen sulphide is replaced by N-methylmorpholine-N-oxide (NMMO). Lyocell fiber has higher tensile strength (until 0,55GPa) and elastic modulus (until 25GPa) with respect to the viscose fiber (until 0,40и 10GPa, respectively). However, using NMMO as a direct solvent is dangerous. In fact, already at a temperature slightly above 140˚C NMMO begins to decompose with the formation of N-methylmorpholine, morpholine and the release of oxygen. This effect leads to formation of explosive mixtures.1,2