Optimization of Conditions for Synthesis of Ultrafine Silver Particles in Hemp Fiber Extract

The impact of conditions in extraction of natural admixtures (pectin compounds, hemicelluloses, and lignin) from hemp fiber during chemical modification of fibrous mass was studied. It was shown that the maximum extraction of admixtures requires increasing the temperature of fiber treatment to 100°С and the sodium hydroxide concentration to 10 g/L. Using infrared spectroscopy and potentiometric titration methods, it was proved that the increase in alkalinity of the boiling liquor leads not only to the increase in the amount of admixtures in the liquor but also to their destruction, while the complex of reducing ingredients that was formed in the liquor can act as a reductant of silver ions even under conditions of low temperatures in extraction. The kinetics of reduction of silver ions in the extract liquor was investigated. The correlation of the efficiency of the reduction of silver ions and the quantitative content of admixtures in the liquor was found. Using photon correlation spectroscopy, it was shown that reduction in an extract obtained under high alkalinity makes it possible to obtain particles of small size, not more than 30 nm. It was proved that the antimicrobial activity of synthesized sols and cellulosic materials treated with these sols against test cultures depends on the synthesis conditions.