ИСТИНА

In recent decades, investigations aimed to the obtaining eco-friendly and renewable materials have attracted an increasing attention. Cellulose that has such properties as biodegradability, non-toxicity, and a good chemical resistance could be a great raw base to produce green materials. Moreover, agricultural and industrial activities generate a large amount of cellulose-containing waste that practically always is being unclaimed due to cellulose infusibility and insolubility at least in all easy-available organic solvents. One of the ways to solve the problem of rational utilization of cellulose waste can be obtaining nanocellulose with its further using in industry. In this research, a new approach to produce cellulose nanoparticles by a precipitant-induced phase separation of cellulosic solution was proposed. This approach included cellulose dissolution in a mixed solvent consisting N-methylmorpholine N-oxide and dimethyl sulfoxide with subsequent regeneration of cellulose under the influence of alkalized water and ultrasound. As a result, nanocellulose was obtained with low degree of crystallinity and good ability to thicken water and polar liquids: its 0.1-0.5% dispersions had a quiet high both effective viscosity and yield stress. Obtained cellulose nanoparticles were used for two purposes. Firstly, nanocellulose was used to emulsifier heavy crude oil in water to decrease its high viscosity. Secondly, nanocellulose was applied as a thickener to produce novel biodegradable low-temperature greases. In both cases, the rheological behavior of aqueous dispersions of nanocellulose was decisive. The effect of nanocellulose concentration on the properties of dispersions and the ability of their application for above-mentioned purposes were investigated. As a result, both greases with high antiwear properties and stable oil-in-water emulsions, which allowed decreasing the viscosity of heavy crude oil in 13 times, were obtained and examined.