An experimental investigation of the effect of pulp types, mechanical treatments and crill contents on fibre network strength

摘要

The strength of fibre networks of various pulp suspensions at 1.0 - 3.0% of mass consistency was measured with a viscometer. And the effects of mechanical treatments and crill content in the suspension on fibre network strength were determined. Results showed that fibre network strength increased with an increase of stock concentration, and the relationship between G' and consistency could be represented in a power law regression equations. Beating and kneading caused reduction of fibre length and elastic stiffness and decreased fibre network strength. The reduction of fibre length lowered the crowding factor as well as the possibility of forming a coherent network or flocculation. Crill addition of pulp suspension decreased the fibre network strength dramatically, especially when the consistency of pulp suspension was low. From regression equations it was shown that the increase of crill content made a values smaller and b values greater. DIP and KOCC pulp suspensions formed weaker fibre network than virgin pulps since they contained significant amount of fines and their fibre quality was deteriorated substantially, which suggested that papermaking with recycled pulps would require less shear or turbulence to disrupt floes. This indicates that these recycled pulps are more suitable for high consistency forming than virgin pulps.