Modified Egyptian talc as internal sizing agent for papermaking

Mineral fillers have long been used in papermaking. The furnish of the writing and printing paper depends on using the fillers as internal or surface treatments. Talc, as an Egyptian filler material, was used as it is or after modification to be used as internal sizing for bleached rice straw pulp. Talc was modified chemically with phthalic anhydride and urea, as well as with using rosin size. Talc is chemically inert. The modification was carried out to change the nature of the native talc. The mechanical and optical properties for internal sizing papers were studied. The results indicated that modified talc with phthalic anhydride enhances the mechanical and optical properties for sized hand-sheets. It was clear that modification of the talc plays a role in improvement of the fiber–filler–fiber bond.