Influence of fibre–fibre joint properties on the dimensional stability of paper

摘要

Measurements have been performed to clarify the connection between fibre–fibre joint properties and dimensional stability using laboratory sheets prepared from never-dried fibres, from heavily hornified fibres having a low molecular contact area between the fibres, and from both hornified and never-dried fibres treated with a polyelectrolyte multilayer (PEM) technique to increase the molecular contact area in the fibre–fibre joint. The influence of the drying mode, i.e. whether the sheets are dried freely or under restraint, was also evaluated. The results showed that neither paper strength nor fibre–fibre joint contact area had any significant influence on the dimensional stability of sheets dried under restraint. On the other hand, when the sheets were dried freely, the PEM-treated sheets expanded to the same extent as, or to an even greater extent than the non-PEM-treated sheets, even though they adsorbed less water for a given change in relative humidity. There was also a correlation between drying shrinkage and dimensional stability, where greater shrinkage was associated with a greater hygroexpansion in the freely dried sheets.