A comparative study of the effect of refining on physical and electrokinetic properties of various cellulosic fibres

The aim of this work was to study the influence of refining on various pulp properties such as freeness, specific surface area, specific volume, surface charge, total charge and elastic modulus. The results indicated that specific surface area of the pulps increased with increased refining, and at the same freeness level the pine pulp exhibited higher surface charge, surface area, and specific volume than the eucalyptus pulps. Also, the eucalypt pulps were much easier to beat than the pine pulps. The total fibre charge, as determined by conductometric titrations, was not affected by refining. However, the surface charge, as determined by titrations with poly-DADMAC, increased with refining. Increasing the specific surface area by refining resulted in a higher fibre surface charge and better fibre–fibre bonding. The change of the fibre surface charge during refining could be monitored using the FTIR characteristic bands within 1700–1300 cm−1.