Chemical modification of cellulose from oat hulls

This study aims to experimentally demonstrate the feasibility of obtaining a high-quality rapid test matrix from oat hulls, a low-cost lignocellulosic cereal raw material. Cellulose was isolated via nitric acid or hydrotropic methods followed by nitration under identical conditions. A correlation was established between the isolation method, the degree of polymerization, and the component composition of cellulose. The study determined that only the nitric acid method yields high-viscosity cellulose with a degree of polymerization of 1040–1550 and an α-cellulose mass fraction within the range of 91.0–94.9%, which are comparable to those of cotton cellulose. Conversely, the hydrotropic method isolates low-viscosity cellulose with a degree of polymerization of 210–720 and an α-cellulose mass fraction of 91.3–91.6%, values close to those of microcrystalline cellulose. The experimental cellulose nitrates are characterized by a yield spanning a wide range of 127–162%, a nitrogen mass fraction of 10.54–12.35%, a solubility in an alcohol-ether mixture of 91–98%, and a viscosity of 3–64 mPa·s. The reproducibility of the cellulose nitrate properties was demonstrated for varying characteristics of the starting cellulose. The findings confirm the viability of manufacturing nitrocellulose membranes via the nitric acid method to obtain high-degree-of-polymerization cellulose from oat hulls, which would ensure maximum stability of the physicochemical properties of the resulting cellulose nitrates.