Nanocellulose, has been utilized in various fields, such as natural fiber-reinforced composites, natural binders, biotechnology, and medicine, as well as energy and electronics.¹ However, the demanding energy consumption and transportation in the presence of excessive water content limited nanocellulose in large-scale application. Herein we comparatively tested the addition of six different types of polysaccharides (PS), i.e., carboxymethyl cellulose (CMC), cationic guar gum (CGG), carboxymethyl O-acetyl-galactoglucomannan (cm-GGM), O-acetyl-galactoglucomanan (GGM), cationic O-acetyl-galactoglucomanan (cat-GGM) and xylan, interfering fiber-to-fiber interaction of microfibrillated cellulose (MFC) in suspension for producing nanocellulose during homogenization step.

In the present study, the understanding of PS contribution in nanocellulose production was investigated in the courses of size-distribution, morphology and redispersibility, etc. Prior to homogenization, the MFC/PS suspensions were rigorously blended for 6 hours to achieve effective PS adsorption to fiber surface. Among different PS matters, it´s noted that the cm-GGM suspension would aid homogenization process even at a high solid content of 1.5 wt.% compared to the homogenization clogging of the pristine MFC suspension at the consistency above 0.4 wt.%. According to rheology measurement, the blends of MFC/PS displayed a good flow property due to the possibly decreased entanglements or aggregations by interfering the physical interaction between fibers. Meanwhile, the degree of fibrillation of the microscale fibers was inclined to be slightly improved when cm-GGM is applied in comparison to others. It´s also noteworthy that the addition of PS aids the nanocellulose redispersibility after freeze drying. In particular, the so-called hornification phenomenon was significantly diminished while producing nanocellulose using by MFC/cm-GGM as shown in Figure 1. A significant decrease of the hornification during the freeze-drying was achieved along with the improved redispersibility of MFC, which could aid the large-scale MFC or nanocellulose transportation. Besides that, the optical and mechanical properties of the MFC/PS films obtained by casting methods were improved to meet the requirement in a typical application. The addition amount of PS was determined to increase the transmittance rate and tensile strength in a way and to decrease the haze whereas the negative charged PS, eg., cm-GGM was used. Collectively, present work provided a comprehensive insight of mechanically production of nanocellulose with an improved redispersibility by interfering fiber-to-fiber interaction using the additive polysaccharides.



[1] Barhoum, Ahmed, et al., Nanoscale, 12, 22845-22890, 2020.