Filler Modification with Polysaccharides or Their Derivatives for Improved Paper Properties

Particle surface modification via polymer encapsulation is a widely adopted technique for improving the properties and the process of painting, coating, ink printing, adhesives, pharmaceuticals, food, etc. In paper industry, increasing the filler content in paper for improving the paper optical and print properties, and reducing the raw material cost and papermaking energy without sacrificing paper strength has attracted extreme research attention in the past two decades. To improve the bondability of inorganic filler particles to wood fibers and maintain the paper strength at a high filler addition level, filler particles need to be modified by introducing effective functional groups so that chemical, physical or hydrogen bonds between filler and fibers can be formed. One of the approaches for improving the filler bondability is to encapsulate the filler particles with functional polymers. Polysaccharides (such as starch and cellulose) and their derivatives can form strong hydrogen bonds with wood fibers. Coating or encapsulating filler particles with polysaccharides or their derivatives provides a new engineering solution for filler modification. Laboratory studies, pilot trials and mill trials show that the modified fillers have many advantages over the unmodified fillers. This paper reviews the related works that have been done in the area of filler modification using polysaccharides or their derivates. The concept development and mechanism of filler modification with polysaccharides are discussed in detail, and the laboratory and pilot trial results are summarized in this review article.