The potential of endoglucanases to rapidly and specifically enhance the rheological properties of micro/nanofibrillated cellulose

The rheological properties of fluids such as paints, coatings, and cosmetics play an important role in determining the effectiveness and desirability of these materials. Typically, these fluids must be relatively viscous and must exhibit shear-thinning characteristics. Previous work has shown that a variety of fibrous cellulosic materials, particularly nanocellulosic products, can impart shear-thinning characteristics to fluids to which they are added. In the work reported here, highly refined micro/nanofibrillated cellulose (MNFC) was assessed for its potential to impart desirable rheological properties to aqueous systems. When endoglucanases were assessed for their ability to influence the rheological properties of MNFC suspensions it was apparent that significant changes in the viscosity and shear-thinning properties of MNFC could be achieved using very low enzyme loadings (< 0.5 mg/g cellulose) within a relatively short timeframe (< 30 min). It is likely that the observed reductions in viscosity arise not just from reductions in the aspect ratio of the cellulosic fibrils, but also through disentanglement of interfibril interactions resulting from enzymatic smoothing of the fibre surfaces.