1. Carboxymethyl cellulose (CMC) is a good dispersant. CMC colloidal solution is easy to affinity with pulp fibers and filler particles in pulp suspension which increases the negative charge of pulp fibers and filler particles. Based on the principle that particles with the same charge repel each other, fibers and fillers in pulp suspensions thus are more evenly dispersed. Therefore, the evenness and the physical strength of the paper are improved.
2. Through its carboxymethyl and the hydroxyl on the fiber chemical hydration in wet end paper, CMC enhances the bonding force between the fibers of paper. And the bonding force will be further improved by the subsequent physical processing in papermaking. It will directly reflect in the improvements of almost all physical strength indices of the paper.
3. Carboxymethyl cellulose CMC can be used as internal sizing agent. CMC not only increases the sizing degree of papers, but also serves as protective colloid of rosin size, AKD and other sizing agents. CMC promotes AKD to disperse into tiny particles and evenly distribute on the fibers, which delays the hydrolysis rate of AKD and reduce the possibility of its hydrolysates's pollution.
4. CMC has strong affinity with fines and filler particles. CMC in combination with appropriate cationic additives will achieve remarkable synergy effects. For one thing, the one-way retention rate of paper machine will be improved. For another, CMC and cationic additive will promote each other to enhance the retention rate of the additives themselves, attaining more remarkable effects.