Modified kaolin and polyacrylic acid-g-cellulosic fiber and microfiber as additives for paper properties improvements

The paper manufacturing industry converts raw materials into various paper and board products by mechanical or chemical processes known as pulping. Fillers and other additives are added to improve the strength and quality of the paper. Kaolin is used as it is as filler for paper manufacture. Kaolin, in the present study, was modified with the resulting black liquor after alkaline pulping of rice straw. The modification was carried out in order to change its nature. Polyacrylamide and polyacrylic acid grafted with cellulosic fiber and microfiber were added with the modified kaolin to improve the mechanical properties and water absorption. The mechanical properties, sizability, water absorption and dewatering were studied. The results indicated that modified kaolin with the polymer enhances the mechanical properties and the water absorption. It was clear that the prepared sheets can be used for special application that needs higher absorption and faster dewatering time.

► Black liquor resulting from the pulping method was used to modify the kaolin.
► The modified kaolin with commercial starch and cellulosic polymers were added to the paper.
► The added fillers had an effect on the water absorbency and the dewatering time.
► Grafted cellulosic polymers with modified kaolin showed positive effect on the paper properties.