عنوان مقاله [English]
This study was performed to investigate the effects of the type of cationic polymer, cationic poly acryl amid and cationic starch, on performance of nano silica for newspaper pulp and paper improvement. After preparation of chemi-mechanical pulp (CMP) and long fiber bleached Kraft pulp, they mixed together and precipitated calcium carbonate (PCC) was added as filler to the stock. As a retention aid system, the composition of cationic starch + nano silica, and also the composition of cationic poly acryl amid + nano silica were added to the stock. The pulp drainability, first pass retention and also newspaper structural, mechanical strength and optical properties were measured and the obtained data were compared with the witness data. The witness samples were the treatments that used only cationic poly acryl amid as retention aid. The analysis of results showed that the cationic polymer factor had considerable effects on performance of nanosilica for newspaper pulp and paper improvement. The stock that had been treated with the composition of cationic starch + nano silica had better and more drainability and higher first pass retention compare to the stock that treated with the composition of poly acryl amid + nano silica. And also the hand sheets that made with the composition of cationic starch + nano silica, had better formation quality, less porosity and higher mechanical strength properties in higher filler content in paper compare to the hand sheets that made with composition of poly acryl amid + nano silica.