Study of the upgradation of cellulose fibre by chemical modification

Acetylation involves reaction between hydroxyl group present in cellulosic structure and acetic anhydride. Acetylation is expected to reduce the hydrogen bond density between hydroxyl groups, increase water-repelling properties and enhance paper-making characteristics. The experimental acetylation procedure using dimethyl formamide (DMF) solvent and related calculation has been described in this article. The reaction monitored by determination of hydroxyl value at regular reaction intervals. The observation and paper making characteristics have been reported in this article. The idea is to determine the kinetics by using integral method of analysis and examine effect of acetylation on paper making characteristics. The acetylation reaction is carried out at a room temperature 30°C. The time for the reaction varies between 5 b and 8 h which depends on the hydroxyl value of acetylated pulp. The product is centrifuged, dried in a dryer or oven and dry acetylated pulp flakes are used for papermaking. The acetyl content of acetylated bagasse, bamboo and waste paper pulp are estimated and found to contain 5.26%, 4.96% and 5.11%, respectively. Characterization of acetylated pulp is conducted and hydroxyl values are determined at regular interval. Considerable reduction in hydroxyl value with time is observed using bagasse pulp, bamboo pulp and wastepaper pulp. As per hydroxyl value obtained, hagasse pulp acetylation equilibrium is established after 8 h and low hydroxyl value is found. In case of bamboo pulp highest hydroxyl value, equilibrium is established after 6 h and has waste paper pulp observed intermediate hydroxyl value and equilibrium extablished after 7 h. The first order rate constant, for bagasse pulp, bamboo pulp and waste paper pulp are 0.17 h^-1 0.188 h^-1 and 0.196 h^-1, respectively. The changes in properties of paper after acetylation have been visualized. The acetylation does not bring any change in weight per unit area of pulp as indicated by GMS value. Acetylated waste paper pulp and bagasse pulp do not exhibit change in burst factor at 80 GSM. Acetylation bamboo pulp exhibites 33% increase in burst factor. The effect of acetylation on tear force, tear factor and tearing strength of pulp is found to be remarkable. At lower degree of acetylation, the enhancement in tear factor is very high. With further acetylation, the tear factor increase is small and at further increase in degree of acetylation, tear strength decreases. The folding endurance of acetylated bamboo pulp is found to be excellent (almost 100% increase).