MODIFICATION OF PLANT CELLULOSE AND ITS SYNTHETIC ANALOGUE INTO LOW-SUBSTITUTED ESTERIFICATION PRODUCTS

To maintain the competitiveness of Russia in the world market, a strategically important task for manufacturers of high-energy cellulose ethers is to find a worthy alternative to cotton and sulfite cellulose. The two most optimum solutions to replacement of conventional resources to overcome the existing problem can be discriminated: alternative easily renewable plant-based feedstocks and their synthetic analogues as replacements. The present study investigates if two conceptually different feedstocks-the grain-processing waste, oat hulls, and synthetic cellulose derived by electropolymerization-can be used as the precursor of cellulose nitrates. The comparative analysis of the cellulose samples established that the synthetic cellulose sample exhibits a higher quality and a more homogeneous morphological structure of cellulosic fibers, as opposed to the cellulose sample isolated from oat hulls. X-ray diffraction discovered that both celluloses match cellulose I beta and the crystallinity values are over 60%, namely, 77.0% for synthetic cellulose and 64.4% for oat-hull cellulose. The resultant cellulose nitrates have the following basic properties: 11.61-11.74% nitrogen content, 93-200 mPa center dot s viscosity, and the same solubility in alcohol-ether mixture at 91%. The morphological features of the cellulose nitrates obtained from both feedstocks were characterized by scanning electron microscopy. FTIR Fourier spectroscopy confirmed the synthesized products to be low-substituted nitric-acid cellulose esters. The crystallinity values calculated from the X-ray patterns by two ways were 4.7-10.0% for the oat-hull cellulose nitrates and 7.0-13.0% for the synthetic cellulose-derived cellulose nitrates, that is, the cellulose is amorphous as a result of nitration. The d-spacing in the X-ray diffraction patterns of the crystalline component of the cellulose nitrates was shown to be consistent with the literature data for the pseudo-orthorhombic phase of cellulose trinitrate. The findings reported justify the expediency of using the new alternative sources as the precursor of cellulose nitrates, with synthetic cellulose being of choice.