A novel approach in increasing carboxymethylation reaction of cellulose

Abstract

Carboxymethyl cellulose (CMC) with a high degree of substitution (DS) was prepared from hardwood bleached pulp by a novel method. In this method, pulp was refined in PFI mill and/or enzymatically treated prior to carboxymethylation. The DS value of CMC increased from 0.5 to 2.4. The yield and molecular weight of CMC increased with increasing DS value. The correlation coefficient between DS and molecular weight was 0.9992. Spectroscopic, thermogravimetric, x-ray diffraction and scanning electron microscopic (SEM) and titrimetric analyses were performed to confirm the degree of substitution and surface modification of the cellulose. Micrograph and SEM image confirm surface modification of cellulose in prior treatment. A comparison of the FTIR spectra of the prepared CMC and standard CMC shows the presence of bands corresponding to ˗O˗, CH2˗ and ˗COO in the CMC, while these bands do not appear for cellulose. The crystallinity of untreated pulp was slightly decreased, while the crystallinity of the prepared CMCs was diminished.

Keywords

• Carboxymethyl cellulose
• Degree of substitution
• Molecular weight
• PFI refining
• Cellulase treatment