Date of Award


Degree Name

Bachelor of Science


Pulp and Paper Technology


This thesis attempts to determine the importance of shearing forces in the strength development of a pulp.

Theoretically, if these shearing forces are able to flex the fibers and thereby reduce their stiffness, it follows that more intimate fiber to fiber contact will result with a related higher bonded area and consequent increased paper strength.

The pulp was subjected to the shearing forces in a Day sigma blade kneader at a high consistency. The treatment time was increased in sequence in an attempt to obtain the maximum strength development these shearing forces could produce.

The work certainly demonstrated that shearing forces can play an important role in strength development of a pulp. This does not mean to imply that they necessarily do in the conventional processes, however, for other possibly dominating factors in stock preparation such as fiber bruising may affect the strength development before the shearing forces have had ample opportunity.