Comparative study of the thermal stability of wood treated with lignin-based sol-gel compositions

Abstract

The use of compositions based on technical lignins and silicon mineral compositions based on NFC for the production of flame-retardant materials for the processing of wooden structures is a promising direction in the development of "green" technologies. The main mechanism of action of lignin-based compositions is the process of coke formation on the surface of wood due to solid-phase inhibition reactions of the cellulose matrix. The mineral component of these compositions tends to glassy during drying, which changes the specifics of the protective effect of new materials in the process of high-temperature destruction of wood and cellulose, which is part of it. Thus, the aim of the work is to study the thermal stability of wood treated with compositions obtained as a result of modification of lignin with minerals by implementing the sol-gel technology method. The paper defines the fundamental possibility of expanding the range of applications of hybrid products of a new generation with a specific organization of spatial structure in the technology of preparation of fire-resistant wood. Fire protection is provided by establishing a chemical bond with the wood matrix, which closely interacts with lignin, which is coordinatively bound to the aluminum-silicon component of the composition. All the compositions studied provide group I fire-retardant efficiency with a mass loss of less than 9% during testing. According to the results of thermal analysis of all the samples studied, it was found that the sol-gel-treated wood samples behave approximately identically in the temperature range from 100 to 300 C. With a further increase in temperature, there is a smaller decrease in the residual mass in comparison with untreated wood, where there is a more active decomposition of hemicelluloses and cellulose, which are part of the wood, which indicates the fire-retardant properties of the new compositions.