Cationization of lignocellulose as a means to enhance paper strength properties

Abstract

Chemical modification by attaching functional groups to lignocellulosic pulp fibers might be a strategy for improving the pulp, and thereby, paper properties. Several studies have described positive effects on paper strength properties for handsheets prepared from cationic-modified pulp or pulp fractions. This study addressed whether these effects are related to the cationic groups, e.g., by increasing electrostatic attraction and thus paper strength, or rather side effects of the chemical modification process, e.g., fiber flexibilization. To eliminate or at least minimize these side effects, only the fines fraction, which was already highly flexible, was cationized. While the addition of cationized fines affected various pulp and paper properties, most notably drainage time, no difference in strength properties was observed when comparing the addition of cationic or unmodified fines to different pulps or fractions thereof.

Partial Replacement of Cationic Starch by Cationic Hardwood Kraft Lignin Does Not Compromise Key Paper Properties

“…The values for all other variants were quite similar, varying in the range of 12.7-16.7 s per 100 mL of air, and being clearly lower than the air resistance values of the starch/lignin-free control handsheets (22.2 s/100 mL). This is in good agreement with a previous study demonstrating that the cationization of lignocellulosic pulp fibers decreases drainage time during sheet formation as reflected by the low air resistance [50]. Only at quantitative replacement of starch, a somewhat higher air resistance (CL-A-100%: 22.7 ± 2.3; CL-B-100%: 25.6 ± 1.1 s/100 mL) similar to that of the control specimens (22.2 ± 2.4 s/100 mL), was measured.…”