Effect of CMC and Surfactant on the Physical Properties of Micro Nanofibrillated Cellulose Coating Colors

Lignocellulosic Materials Research Centre, Canada

Abstract: Rheological characteristics and physical properties of the micro nano fibrillated cellulose suspensions play an important role in curtain coating of paper. In curtain coating layer, curtain stability remains an issue to control the coating operation. The curtain stability is associated with rheological characteristics and physical properties of the micro nanofibrillated cellulose (MNFC) suspensions such as the viscosity and dynamic surface tension. Thickeners are used to control the viscoelasticity of the MNFC suspensions. Use of surfactant has been recognized as useful approach to increase the curtain stability because low dynamic surface tension is desirable to get a stable liquid flow. Effect of carboxymethyl cellulose (CMC) and anionic surfactant (Niaproof4) on viscoelasticity and dynamic surface tension was examined and compared. The change of air bubble content brought was also investigated. Our study showed that CMC didn’t influence the dynamic surface tension of MNFC suspensions. Conversely, viscoelasticity decreases with increasing the amount of CMC in the MNFC suspensions. Furthermore, surfactant didn’t have effect on viscoelasticity of MNFC suspensions but decreases significantly dynamic surface tension. In addition, we have observed that the use of CMC increases air content, but surfactant was more effective. The use of both at once generates more air bubbles in the MNFC suspensions.