Evaluation of Mechanical and Optical Properties of Modified Bagasse Chemi-mechanical Pulp through Acetylation in Liquid Phase.

Unbleached and hydrogen peroxide bleached bagasse chemimechanical pulp were acetylated in liquid phase in order to investigate the change in paper properties due to chemical modification. The acetylation treatment was carried out on paper sheets and pulp samples. Effect of liquid phase acetylation on optical and mechanical properties of bagasse chemimechanical paper sheets was evaluated. The obtained results also indicated that acetylation is a reliable method to eliminate phenolic hydroxyl groups. Paper made from unbleached CMP increased in brightness (up to 10 percentage units) on acetylation, while the hydrogen peroxide bleached paper decreased in brightness. The acetylation treatment removed or inactivated some chromophores originally present in the unbleached CMP but not in the hydrogen peroxide bleached samples. The results showed that partial acetylation even for short period of times could cause considerable increase in wet strength of paper, due probably to lower equilibrium moisture content. Also, other mechanical properties such as tear resistance and tensile strength were not affected to any great extent by acetylation in liquid phase providing that the paper sheet is acetylated instead of pulp. Present study proved that active phenolic hydroxyl functional groups present in pulp could be modified without losing mechanical strengths and optical behaviour of the paper.