Chemical transformations of flax shive lignin under the impact of fermentation products of polysaccharides

Abstract

The actual problems of using flax production waste for obtaining products which are necessary to produce cosmetics with sunscreen and antioxidant properties were studied. Preparations were obtained of ethanolignin from flax shives and raw materials that have subjected to alkaline pulping or biochemical modification. The bio-processing included the stage of enzymatic degradation of non-cellulosic polysaccharides with the generation of aldoses and stage of isothermal aging at 95^о С. Chemical transformations in the polymer were studied by Fourier-transform infrared spectroscopy (FTIR) with the decomposition of spectral curve into elementary vibration bands in the main atomic groups. The analysis of the spectra was carried out using the C-C stretching vibrations in the aromatic ring at 1510 сm^–1 as the internal standard. In spectra of hydrolyzed lignin an increase of absorption oxyaryl groups is combined with an increase in the band intensity of valence and deformation vibrations of C=C bond in alkene fragments. The enhancement of the auxochromic effect in double bonds adjoin to the aromatic ring is manifested as the increase of absorption in the nearultraviolet and visible light ranges. The biochemical preparation of the raw material provides the disappearance of the bands double bond in the carbonyl and alkene groups in the IR spectra. It is accompanied by strengthening in the absorption bands of alkyl hydroxyls by 1.5–2 times and hydroxyl group in the oxyaryl units by 3—4 times. The results are consistent with the data of analysis of biomodified preparation by the differential UV spectroscopy method and testify strengthening of photostabilizing ability of lignin in a combination with absolute transparency in the visible range.