Arabinogalactan application for wood mineralization

Abstract

Formulation and technological solutions aimed at improving the physico-chemical and physico-mechanical characteristics of pine wood construction materials by mineralization of the plant raw materials matrix due to its treatment with an aqueous organomineral suspension based on arabinogalactan and pre-mechanoactivated silica-containing sand have been developed and scientifically substantiated. The natural polysaccharide arabinogalactan isolated from larch wood can act as a stabilizer of aggregation and sedimentation stability of suspension particles for wood processing. Experimental data on the thermal effect calorimetric measurement of the enthalpy of complexation for a series of experimental samples with different contents of a silica-containing component are presented. The results confirming the high efficiency of arabinogalactan as a surfactant have been obtained. The fact of the formation of a chemical bond during the impregnation of wood samples with an organomineral suspension between organic macromolecules (cellulose, lignin, hemicellulose) of vegetable raw materials and silica of the mineral component was found, which contributes to the consolidation of the latter in the structure of the wood matrix. Mineralization of the wood surface with compositions containing arabinogalactan and silica nanoparticles gives an increase in density and hardness, as well as the acquisition of hydrophobic properties and resistance to oxidative degradation. This indicates the possibility of using this composition for petrifying wood. The kinetic description of the complexation process is given, the conditions of stable long-term existence of the complex in an aqueous medium are established. It is shown that the treatment of wood with suspension for 24 hours in a spontaneous mode with a rationally selected composition leads to an increase in the density of vegetable raw materials by 10 %, an increase in strength along the fibers by 80 %, Brinell hardness by 3,4 times. Impregnation of wood samples in autoclave mode with a similar suspension (under an excess pressure of 1,35…1,40 MPa) significantly intensifies the process of mineralization of plant raw materials. Thus, over a time period of 24 hours, the density of wood increases by 70 %, the increase in strength along the fibers was 91 %, Brinell hardness increases by 3,5 times, water absorption decreases by 21 %. It was found that the impregnation of wood with a suspension of the developed organomineral composition does not lead to a change in the geometric dimensions and texture of the samples.