양이온성 고분자전해질을 적용한 셀룰로오스 나노피브릴의표면전처리 연구

Abstract

It is important to retain the surface charge of cellulose nanofibrils (CNFs) on the wet web when they are used as a dry strength agent in the papermaking process. CNFs typically contain negative charges due to the carboxylic acids on cellulose molecules. Surface modification of CNFs should therefore be carried out to improve the retention of CNFs. In this study, we treated the CNFs with polyethyleneimine (PEI), polydiallyldimethyl ammonium chloride (P-DADMAC), and cationic polyacrylamide (C-PAM), and the zeta potential of the CNFs was measured to identify surface modification. Subsequently, the handsheets were made using these pretreated CNFs and the strength of the handsheets was measured. Charge reversion in the CNFs was observed as negative to positive zeta potential as the addition of polyelectrolytes increased, but the reversion points were different according to the type of polyelectrolyte used. C-PAM handsheets showed higher tensile strength and folding endurance than the other two polyelectrolytes. It was therefore concluded that C-PAM was the most effective polyelectrolyte for modifying the surface charge of CNFs when used as internal additive in the papermaking process.