A novel method for producing cellulose nanoparticles and their possible application as thickeners for biodegradable low-temperature greases

• DOI: 10.1007/s10570-021-04166-1
• Publication Date: 2021-09-05T08:02:41Z
• Authors: Svetlana N. Gorba...; Anastasiya Y. Yad...; Sergey O. Ilyin
• Keywords: 02 engineering and technology; 0210 nano-technology

A novel method for producing micro- and nanoparticles of cellulose by phase separation of its solutions in the mixture of N-methylmorpholine N-oxide and dimethyl sulfoxide initiated by cooling or adding a precipitant has been suggested. The effect of the nature of the precipitant (water, methanol, or butanol) on the size and crystallinity of cellulose particles as well as their ability to act as thickeners has been investigated. In all cases, the regenerated cellulose was amorphous in nature, while only the use of alkaline water for precipitation allowed producing nanoscale particles of nanocellulose. Rheological properties of aqueous and alcoholic dispersions containing cellulose with concentration up to 3% have been considered. It turned out that the size and origin of the cellulose particles had very little effect on the rheology of the dispersions, which exhibited typical gel properties. Synthesized nanocellulose was used then as a thickener agent to obtain biodegradable low-temperature greases based on polar base oil—triethyl citrate. Tribological and rheological properties of the resulting lubricants have been investigated. Introduction of 7% nanocellulose made it possible to obtain a grease of medium consistency with high wear protection and low friction coefficient under high loads.