Synthesis and characterization of carboxymethylcelluloses (CMC) from non-wood fibers I.: Accessibility of cellulose fibers and CMC synthesis

This paper explores the production of carboxymethylcellulose (CMC) from several bleached cellulose pulps obtained from non- wood species. The chemical composition ( alpha- cellulose, hemicellulose and lignin content), the degree of swelling, viscosity, solubility in concentrated NaOH and crystallinity of soda/ AQ cellulose pulps from abaca, jute, sisal, linen and Miscanthus sinensis were determined. The pulps were carboxymethylated by one and two successive reaction steps in aqueous medium under identical conditions. The degree of substitution (DS) of CMC was found to be dependent upon the source of the cellulose pulp, but generally it was close to 1 with one etherification treatment and around 2 after the second. The molar mass of CMC was found to be dependent on the initial intrinsic viscosity of the cellulose pulp. The weight average molar mass of our CMCs ranged from 1.5 x 10(5) to 2.8 x 10(5). Increasing the DS up to 2 improved the CMC solubility, but viscosity slightly decreased due to a slight degradation of the polymer.