Production of textile filaments from carboxymethylated cellulosic pulps

Abstract

Textile filaments were fabricated from a solution obtained from carboxymethylated cellulose dissolved in aqueous NaOH solution, by wet spinning in an acid coagulation bath. Spinning is possible for modified cellulose with a carboxyl group content of at least 1.3 mmol/g cellulose. A post-treatment—heating in the presence of sodium hypophosphite—improved the properties of these filaments. This is a novel process, much more environmentally friendly than the viscose process for the production of rayon, in which most of the chemicals can be reused making it likely that the process is economically viable. After extrusion in an acid bath, filaments containing 1.3 mmol –COOH/g cellulose could be washed with water quite readily, a process very difficult for filaments with carboxyl group content of 1.5–1.7 mmol/g cellulose. The tenacity of the filaments obtained from the modified cellulose with a carboxyl group content of 1.3 mmol/g cellulose was 1.0 cN/dtex, which was higher than that of the filaments with carboxyl group contents of 1.5 mmol/g cellulose (tenacity 0.93 cN/dtex) and 1.7 mmol/g cellulose (tenacity 0.88 cN/dtex). The water absorbency of the filaments made from the modified cellulose with carboxyl group content of 1.3 mmol/g cellulose was 0.54 g water/g filaments which was ~ 2 times and ~ 3.5 times lower than that of the filaments with carboxyl group contents of 1.5 mmol/g cellulose and 1.7 mmol/g cellulose, respectively. The values of tenacity and water absorbency for filaments with 1.3 mmol/g cellulose are extremely promising for textile applications.

Graphical abstract