Hydrophobization of cellulose spathellas obtained from Sosnowsky hogweed stem with solutions of tetrafluoroethylene telomers

Abstract

The process of obtaining cellulose from the Sosnowsky hogweed stem and spathellas from this cellulose is described in detail. The task is relevant from the point of view of the use of this weed. The elemental composition and properties of the obtained cellulose samples were studied by elemental analysis, infrared (IR) spectroscopy, X-ray powder diffractometry, differential scanning calorimetry (DSC), and X-ray photoelectron spectroscopy (XPS). The study of IR spectra and X-ray patterns of cellulose made it possible to determine the degree of its crystallinity (65…75 %). The glass transition temperature (105…108 °C) of the samples was estimated from the results of DSC. A comparative analysis of the characteristics of the obtained cellulose with the available literature data was carried out. The treatment of spathellas obtained from cellulose with solutions of radiation-synthesized tetrafluoroethylene (TFE) telomers made it possible to obtain a hydrophobic material with a contact angle exceeding 140°. For hydrophobization, we used TFE telomers synthesized in acetone, the binary solvent Freon 113 + ammonia, and Flutec PP3, which have different terminal groups. It has been established that the interfacial angle of the surface of a cellulose spathella treated with telomers depends both on the composition (end groups) of the telomer and on the initial concentration of TFE at which the synthesis was carried out. The optimal concentration of TFE for the synthesis of telomers in Flutec PP3 has been determined. The presence of a fluoropolymer coating of the spathella, which ensures its hydrophobicity, was confirmed by XPS results.