Study of the effect of ultra-high frequency radiation on the mechanical properties of larix sibirica wood

Larix sibirica wood is a promising object for obtaining modified wood. However, due to the low natural permeability of heartwood, its impregnation with modifying compounds is practically impossible. Microwave treatment is an effective way to increase the permeability of heartwood. This exposure makes it possible to multiply the permeability of wood for liquids and gases. A negative factor of the exposure of microwave radiation is the local destruction of the structural elements of wood, which, under intense irradiation, leads to a decrease in the strength properties of wood. The work presents the results of the researches of the impact of microwave treatment on the mechanical properties of Siberian larch wood. Within the framework of the research, the impact of the microwave treatment on the mechanical properties of larch wood was studied. For the purposes of the research, microwave treatment of Siberian larch heartwood with an initial moisture content of 53% was carried out. Specific microwave power is 7500 kW / m³. Duration of the treatment is 270 s. After the microwave treatment, the wood was tested for compressive strength, bending strength, and shear strength. The results of the researches show that the microwave exposure did not affect the larch wood strength when compressed along the fibers. Wood bending tests revealed some reduction in strength when a load was applied in the tangential direction. Whereas in the radial direction, the bending strength remained unchanged. Wood shear test in the radial plane showed a sharp (50%) decrease of the strength of wood treated with microwave in comparison with control samples. At the same time, wood treated by microwave and shear tested wood in the tangential plane did not show a decrease in strength.