The Role of TMP Fines in Interfibre Bonding and Fibre-Segment Activation

摘要

The effect of fines on interfibre bonding and fibre-segment activation was investigated with the help of drying experiments. Thermomechanical pulp (TMP) fines increase the tensile strength of the test sheets, independent of the amount of drying strain introduced into the sheets. When the sheets are strained more at the beginning of drying, tensile stiffness increases considerably. Increasing the amount of fines in the furnish leads to increasing tensile stiffness, or activation. One explanation is that fines are deposited near the bonded areas and their corners so that the lengths of free segments shorten, making the segments easier to activate. Fines have greater shrinkage potential, which leads to greater stress, forcing the free segments to straighten and activate during drying. As the amount of fines in the test sheets increases, bond strength increases significantly. No amount of fines together with long fibres can raise the level of bond strength to that of unfractionated TMP sheets.