EFFECTS OF BALL MILLING AND ENZYME TREATMENT ON CELLULOSE ACETYLATION

Abstract

A novel process was developed to produce cellulose acetate from bleached hardwood kraft pulp (BHKP) through ball milling and cellulase treatment. The ball milling and/or cellulase treatment of BHKP increased the esterification reaction, but enzyme treatment reduced the viscosity of the produced cellulose acetate (CA). The degree of substitution (DS) values upon acetylation were 2.26 for BHKP, 2.61 for ball-milled BHKP and 2.91 for ball milled followed by cellulase treatment of BHKP. The prepared CA was also characterized by FTIR, XRD, TGA, 1H-NMR and SEM. A strong band for –OH stretching of cellulose disappeared and created a strong band for carbonyl (C=O) group on esterification of BHKP. The crystallinity index of BHKP was 63.3%, which completely disappeared on acetylation, demonstrating the successful esterification of cellulose. The initial weight loss of cellulose acetates was lower than that of the native cellulose, as observed in TGA, indicating the acetylated samples are less hydrophilic. 1H NMR spectroscopy confirmed the complete structure of cellulose acetate.