Reactivity of alkoxysilanes with cellulose and lignin in presence of catalysts

IRG/WP 18-40831

J Siuda, W Perdoch, B Mazela, M Zborowska

The origin of research was another step in development of a new conservation method for wood cultural heritage. Wood silanisation seemed to be an alternative method to waterlogged wood PEG treatment. The superior aim from the practical point of view was to increase dimensional stability and reduce the hygroscopicity of archaeological wood. The aim of the study was to identify interactions between wood main components and selected alkoxysilanes. Celullose and lignin were modified with alkoxysilanes in presence of catalysts. The scope included methyltrimethoxysilane (MTMOS) and methyltriethoxysilane (TEMS) as modifying agents. Aluminium acetylacetonate (Al(acac)3) and acetic acid (AcOH) were used as catalysts. Samples were measured by using FT-IR. It turned out that cellulose was not so readily reactive to alkoxysilanes as lignin. However, cellulose can react with silanols, which are the product of hydrolysis of alkoxysilanes. For this purpose, catalysts were used to enhance the durability of the interactions between alkoxysilanes and wood main components. In case of lignin, no catalyst addition was needed. In case of cellulose, results clearly showed better reactivity of alkoxysialnes in the presence of catalysts. These results are confirmed by peaks on spectra appeared at e.g. 1270 cm-1 and 777 cm-1. Depending on the formulations the intensity of peaks were different between each other. They corresponded to the Si-CH3 groups. In the case of lignin, peak at 920 cm-1 corresponded to Si-OH bonds which proved that hydrolysis was occurred.


Keywords: cellulose, lignin, methyltrimethoxysilane, methyltriethoxysilane, hydrolysis

Conference: 18-04-29/05-03 Johannesburg, South Africa


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