EXTRACTION OF ORGANOSOLV PULP AND PRODUCTION OF NANOCELLULOSE FROM HEMP FIBRES

Abstract

Background. The use of cellulose and nanocellulose instead of synthetic polymers makes it possible to improve the consumer properties and environmental friendliness of composite materials. Therefore, the development of technologies for the production of organosolv pulp and nanocellulose from plant raw materials, in particular from hemp fibres, is an urgent scientific and practical problem. Objective. The purpose of the paper is to obtain pulp from hemp fibres by the peracetic method and to study the effect of the concentration of sulfuric acid and the temperature of hydrolysis of organosolv pulp on the quality parameters of hemp nanocellulose. Methods. Treatment of hemp fibres was performed in two stages: alkaline extraction and organosolv cooking at a temperature of 97±2 °C. Nanocellulose was obtained by hydrolysis with a solution of sulfuric acid of various concentrations. The resulting nanocellulose was examined by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and atomic force microscopy (AFM). Results. Organosolv hemp pulp with a residual lignin content of 0.16% and an ash content of 0.08% was obtained. The nanocellulose particles obtained from it had a transverse size of 8–36 nanometers and a length of several micrometers. Nanocellulose films had high mechanical properties: density up to 1.54 g/cm3 and tensile strength up to 60 MPa. Conclusions. Carrying out thermochemical treatment of hemp fibres in two stages makes it possible to obtain pulp with a minimum residual content of lignin and minerals, which is suitable for the production of nanocellulose. Nanocellulose has been successfully isolated from organosolv hemp pulp by acid hydrolysis. Subsequent ultrasonic treatment allows obtaining a stable nanocellulose gel with high mechanical properties.

Keywords

• hemp fiber
• organosolv pulp
• nanocellulose
• acid hydrolysis