4 - Cellulose in Aqueous Sodium Hydroxide

Abstract

This chapter reviews the experimental findings and the preparation of cellulose in aqueous sodium hydroxide. A process pertaining to cotton fabrics by treating cellulose with aqueous (aq.) alkali solution under tension—the swelling phenomena of cellulose with aq. alkali solution is called the process of mercerization of cellulose. Cellulose contains the alkali soluble part that is used to evaluate the lateral order distribution of cellulose fibers without considering the molecular weight fractionation effect by the alkali. It has been accepted that without direct evidence only the difference in the aggregate state of cellulose molecular chains influences the solubility of cellulose towards alkali. The regenerated cellulose is prepared under special conditions and is completely soluble in a 10 wt% aq. sodium hyroxide (NaOH) at 4 °C. The chapter also discusses the solubility of cellulose in terms of intramolecular hydrogen bonding. The cellulose fibers and films wet spun are derived from cellulose aqueous alkali solution in four stages, namely preliminary wet spinning test, laboratory scale wet spinning, small size bench scale wet spinning, and bench plant wet spinning net process. Therefore, cellulose multifilaments with mechanical properties, equally matched to those of commercially available viscose filaments, can be produced by net process at the spinning velocity almost equal to that of viscose. The new cellulose fiber is an environment friendly innovation, offering outstanding potential as an alternative to the present commercially regenerated cellulose fiber, especially viscose and cuprammonium rayons.