Nanocellulose–cationic starch– colloidal silica systems for papermaking: Effects on process and paper properties

Laboratory tests were conducted to better understand effects on the papermaking process and handsheets when recycled copy paper furnish was treated with combinations of nanofibrillated cellulose (NFC), cat-ionic starch, colloidal silica, and cationic retention aid (cPAM; cationic polyacrylamide). Dosage-response experiments helped to define conditions leading to favorable processing outcomes, including dewatering rates and the efficiency of fine-particle retention during papermaking. Effects were found to depend on the addition amounts of cationic starch and colloidal silica added to the system. It was shown that the presence of a polymer additive such as cationic starch was essential in order to achieve large strength gains with simultaneous usage of NFC.