Stroitel’stvo: Nauka i Obrazovanie (Jun 2018)
CHANGE IN THE SUPRAMOLECULAR STRUCTURE OF CELLULOSE IN THE PROCESS OF ANTISEPTIZATION OF WOOD WITH MONO-ETHANOLAMINE(N→B)-TRIHYDROXYBORATE
Abstract
Subject of research: research of the relation between the change in the supramolecular structure of cellulose as a result of modifying by mono-ethanolamine(N→B)-trihydroxyborate and the bioproofness of the modified pine wood. Objective: the research of influence of secondary crystallization of cellulose when subjected to mono-ethanolamine(N→B)-trihydroxyborate on the bioproofness of the modified pine wood. Materials and methods: samples of air-dry cellulose with the size of particles of 1 × 1 mm and samples of pine wood with the size of 50 × 50 × 10 mm, the latter is parallel to the grain, were used. As a modifier the aqueous solutions of mono-ethanolamine(N→B)-trihydroxyborate (MB) of various concentrations (10, 30, 50 % of mass fraction) were used. The samples of cellulose were modified by the method of immersion into solutions of modifiers. The modifying was conducted at the room temperature during three hours, the excess of modifiers was removed through extraction by distilled water. The modified samples were dried at the room temperature to the constant weight. The samples of pine wood were modified by the method of modifier brushing on the wood surface. X-ray diffraction analysis was conducted with the application of the diffractometer of Scientific brand, ARL X’TRA Termo model, produced by TermoElectron SA (Switzerland), using the radiation of λ[CuKα] = 1.5418 Å and a rotating-sample Ni-filter. The wood samples tests concerning the resistance to the impact of mold and wood-destroying fungi were conducted in the laboratory of tropical technologies of A.N. Severtsov Institute of Ecology and Evolution (IEE RAS) pursuant to methods of GOST Standard 9.048-89. Results: it was determined that the modifying of cellulose by mono-ethanolamine(N→B)-trihydroxyborate leads to the change in its supramolecular structure: the increase of crystallinity degree due to the secondary crystallization. The increase of cellulose crystallinity degree results in the improvement of bioresistance of the modified wood and intensifies the antiseptic action of mono-ethanolamine(N→B)-trihydroxyborate. Conclusion: high efficacy of mono-ethanolamine(N→B)-trihydroxyborate as an antiseptic is conditioned by its impact on the supramolecular structure of cellulose and the toxic effect on mold and wood-destroying fungi. The most suitable concentration of the modifier is a 50 % aqueous solution with consumption of 150…200 g/m2. The application of antiseptics, increasing the cellulose crystallinity degree as a result of chemical modifying is one of the possibilities to improve bioproofness of the wood in the process of its surface treatment.
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