Effect of pulp composition on the characteristics of residuals in CMC made from such pulps

Abstract

Four different spruce sulphite pulp samples were used for the preparation of carboxymethylcellulose (CMC). The characteristics of the unreacted fibre and particle residuals obtained in the CMC-preparation were used to establish a correlation between the hemicellulose in the pulp and the intrinsic viscosity, i.e., cellulose chain length and the occurence of unreacted residuals. It was shown that the residual particles in the CMC consisted of fibres, fibre fractions and gel particles of different degrees of substitution. The results suggested that pulps with long cellulose chains, i.e., pulps with high intrinsic viscosities, resulted in particles that were more substituted and more swollen. These pulps also resulted in more substituted hemicelluloses in the CMC and more substituted residuals. It was also suggested that galactoglucomannan in the cellulose pulps is favourable for the swelling which results in more substituted hemicelluloses in the CMC and more swollen residuals. The amount of residuals was influenced mainly by the characteristics of the cellulose in the pulp. It is therefore believed that a combination of high viscosity and a suitable combination of hemicelluloses is the most favourable way of eliminating the occurrence of undissolved residuals in CMC.

Characterization of Sodium Carboxymethyl Cellulose Aqueous Solutions to Support Complex Product Formulation: A Rheology and Light Scattering Study

“…Jardeby and co-workers have previously isolated particulates from Na CMC solutions (see Figure S1 and Jardeby and co-workers' papers 29,71,72 ) using filters, and the same filter types (i.e. ROBU ® VitraPOR ® Borosilicate 3.3 filter tunnels) were thus tried in the present study, using the smallest available pore size (1.0-1.6 m).…”

“…The crystallinity of the cellulose raw material, 3,25,27 and/or the amount and the distribution of the carboxymethyl groups along the chains. 3,19,[28][29][30] can also vary. Commercial Na CMCs typically have an average of 0.4-1.5 carboxymethyl groups per monomer, which is referred to as the absolute Degree of Substitution (DS).…”

“…If there are not enough of these groups and/or if they are not homogeneously distributed along Na CMC chains, Na CMC chains or chain sections are not fully solubilized in water. 3,28,29 The rheological behavior of Na CMC in water, with or without other compounds (e.g. salts, 16,[30][31][32][33] sugars, 33,34 or surfactants 31,35 ), or in solvents such as glycerin/water mixtures, 32 propylene glycol/water mixtures 36 or cadoxen 37 has been characterized.…”

“…Given the biological origin of Na CMC, it typically has a high polydispersity of the chain length distribution ,,, (common values of M w / M n are around 1.7–4.5 ,,,, ). The crystallinity of the cellulose raw material ,, and/or the amount and the distribution of the carboxymethyl groups along the chains ,,− can also vary. Commercial Na CMCs typically have an average of 0.4–1.5 carboxymethyl groups per monomer, which is referred to as the absolute degree of substitution (DS). , These charged carboxymethyl groups are key to the behavior of Na CMC in solution as they confer its water-solubility to Na CMC.…”

Novel Treatment Route for Preparation and Characterization of Carboxymethyl Cellulose

“…In the second step, monochloroacetic acid or its sodium salt is added. 14 The first step includes shredding of naturally-occurring cotton fibers, followed by dissolution and conversion to alkali cellulose in presence of solvents including isopropanol and water, 15 N,N-dimethyl acetamide (DMA)/LiCl, 16 N-methylmorpholine-N-oxide, 17 aqueous cellulose solvent Ni(tren)(OH) 2 [tren-tris(2-aminoethyl) amine], 18 and triethylamine (TEA). 19 Recently, partial carboxymethylation of cellulosic fabric has been carried out based on methods involving no dissolution and cellulose shredding using conventional textile wet processing equipment and methods.…”