Combination of enzymatic, mechanical and ultrasonic treatments for improvement of the properties of secondary pulps

Abstract

This study evaluated the property recovery capability of handsheets formed from secondary fibers by combining different techniques. To attain that, pulps derived from post-consumer cardboard scrap were subjected to various refining intensities respectively in a PFI mill (0, 400, 800 and 1200 revolutions) and ultrasound (0, 10, 20 and 30 minutes), followed by enzymatic treatments with enzymes Cellulase, Hemicellulase, Mixture 1 and Mixture 2 (both mixtures composed of cellulase and hemicellulase). The papermaking potential of the pulps was evaluated by means of physical and mechanical tests on the resulting paper after the relevant treatments. It was found that both the combination of PFI mill refining with enzymatic treatments and the combination of ultrasound with enzymatic treatments were effective in improving paper properties. It was also found that interfiber bonding properties such as tensile index and ring crush strength had greater increases, in relation to the initial pulp, in pulps derived from the combined PFI mill refining with enzymatic treatments. As for intrinsic fiber strength properties, such as tear resistance, had greater increases in pulps derived from the combined ultrasound with enzymatic treatments.