A SPECIAL REPORT ON H -INFLUENCE OF FIBRE CHEMISTRY ON THE FRACTURE TOUGHNESS OF- PAPER

Abstract

Refining is often used as a tool to improve the strength of the paper sheet and to enhance the paper properties. Almost the same strength properties can be achieved when polyelectrolytes are added to the pulp fibres. The effect of the strength increase due to multilayer formation when more than one polyelectrolyte is added is separated from the strength increase due to the polyelectrolyte entering the fiber wall. An attempt has been made to show that the polyelectrolytes enter the fibre wall and thereby strengthen the paper sheet. Significant strength increase was seen when PAH and PIMA were added. It was•inferred that it was due to the polyelectrolytes entering the fibre wall and reacting. Significant strength increase was seen when PAH, CMC and PIMA were added to the fibres. It could not be inferred whether the strength increase was due to to CMC or due to the fact that PAH and PIMA had gone inside the fibre wall and reacted.