Reinforcements of cationic polyvinyl alcohol with low dosage for secondary fibre

Abstract

ABSTRACT The effect of polyvinyl alcohol, a green water-soluble polymer, usually is not satisfied as a secondary-fiber reinforcing agent in pulp and paper-making industry due to the same negative charges of PVA and pulp fiber. In this study, 3-chloro-2-hydroxypropyltrimethylammonium chloride was used as an etherifying agent to prepare cationic modification of polyvinyl alcohol (CPVA) with degree of etherification of 0.059 under a reaction time of 4 hours and n(PVA : etherifying agent) = 1 : 0.5. Compared with PVA, CPVA exhibits positive charge and smaller particle size, enabling it to effectively combine with negatively charged fibers and get in between the fibers. As a result, CPVA demonstrates a remarkable ability to improve the paper’s physical properties. With a dosage of only 0.2% CPVA (based on the absolute dry pulp), which is merely 1/10 of the dosage of PVA, CPVA increases the paper’s tensile index by 54.09%, burst index by 25.96%, and tear index by 21.09%. CPVA as a reinforcing agent for secondary fiber pulps, which can be attributed to the alteration in charge, to enhance CPVA’s affinity for the electrostatic interaction of the fibers. Consequently, CPVA emerges as a viable and eco-friendly enhancement solution, demonstrating significant potential in secondary fiber reuse.