Starch-Fatty Complex Modified Filler for Papermaking

In order to improve filler-fiber bonding in paper, starch-filler composites were prepared by a starch-fatty acid complex formation method. These composites were used as a papermaking filler to improve the physical properties of the paper, filler retention and the sizing effect. The solubility of the starch-fatty acid complex in water at different temperatures was measured. The results indicated that the starch-fatty acid complexes have very low solubility in water below $70^{\circ}C$, which can be easily coated on clay surface to modify clay-fiber bonding ability. The clay-starch composite filled handsheets showed that paper strength could increase more than $100{\sim}200%$ compared to untreated clay. It was found that ZDT of the handsheet decreased as the clay content increased when unmodified clay was used, but it increased when the starch-fatty acid composite modified filler was used. It was also found that the presence of fatty acide in the complex increased the water-repellant property of the handsheet, which can be used to aid in sizing during papermaking. Filler distribution and bonding characteristics between the composite and fiber were investigated using Scanning Electron Microscopy(SEM).