Evaluation of Silica-Coated PCC as New Modified Filler for Papermaking

Silica-coated precipitated calcium carbonate (PCC) prepared by a sol gel method in a previous study, was used, for the first time, as filler for papermaking. Three samples of modified PCC, containing 11, 21, and 29 wt % of silica, were prepared. The handsheets produced with a eucalyptus kraft pulp furnish containing the new PCC-based materials showed better paper strength properties than those with the unmodified PCC, whereas the structural properties and brightness were not affected (for similar filler retention values (ca. 80%)). The results suggest that a thin film of silica coating the calcium carbonate crystals has a positive impact on the filler-to-fiber-to-filler bonding. This may open a new possibility to increase the filler amount in the papermaking industry.