Sag control of waterborne acrylic latex with regenerated nanocellulose suspension

Waterborne acrylic latex has been widely used for its decent performance and less emission of volatile organic compounds. In the present study, regenerated nanocellulose suspension from microcrystalline cellulose (MCC) and wood pulp toward improving waterborne polyacrylate (PA) latex sag resistance was evaluated. Rheology behavior of PA latex-regenerated nanocellulose (RC) was investigated. PA latex-RC displayed a gel-like behavior and had a desirable shear thinning property. Moreover, sag resistance of PA latex was evaluated by creep behavior. Results showed that deformation of PA latex at constant stress obviously decreased with an increase of the RC concentration. Meanwhile, PA latex showed high recovery of strain (> 90%) with 2% RC concentration after removal of stress, which may be related to the reinforcement from the RC entanglements and their interaction. In addition, the properties of dry PA film with RC were also evaluated. The tensile strain, tensile stress and thermal stability of the films were slightly improved, while optical transparency slightly compromised with 2% RC concentration. Overall, the results suggested that RC is a promising biomass material for improving the sag resistance of waterborne acrylic latex.