Starch/rosin complexes for improving the interaction of mineral filler particles with cellulosic fibers.

On the basis of inclusion complex formation of starch with small guest molecules, the concept of filler modification for papermaking by calcium-ion-induced deposition of starch/rosin complexes in the presence of filer particles was demonstrated. The rosin amount of 3% (on the basis of the dry weight of starch) induced effective starch deposition. Due to the cellulose-bondable nature of starch/rosin complexes, filler modification resulted in improved interaction of precipitated calcium carbonate particles with cellulosic fibers, leading to reduced negative impact of filler addition on paper strength. The efficiency of alkyl ketene dimer emulsion as an internal sizing agent for cellulosic paper was also improved as a result of filler modification. The concept demonstrated in this study may provide a useful alternative to the improvement of the use of mineral fillers in the paper industry.