Abstract The work proposes the use of multi-walled carbon nanotubes in various concentrations treated in nitric acid (f-MWCNT) as a filler for urea-formaldehyde resin to produce birch plywood with improved physical-mechanical, water-resistant and thermal properties. The MWCNTs were characterized using transmission electron microscopy, IR and Raman spectroscopy, and the zeta potential was determined. The thermal stability of plywood on the UFR/f-MWCNT adhesive composition was assessed and a higher thermal stability of plywood was revealed when a nanofiller was added to the resin. The modulus of rupture increased by 62.7% and the modulus of elasticity by 113% with the addition of 1.5% f-MWCNT. A decrease in water absorption was established by 43%. A steady decrease in the emission of free formaldehyde from plywood was determined. The possibility of intermolecular interaction between the functional groups of f-MWCNT and urea-formaldehyde resins has been established. multiwalled multi walled fMWCNT f MWCNT (f-MWCNT ureaformaldehyde urea physicalmechanical, physicalmechanical physical mechanical, mechanical physical-mechanical waterresistant resistant properties microscopy spectroscopy determined UFR/fMWCNT UFRfMWCNT UFR/f UFR 627 62 7 62.7 113 15 1 5 1.5 fMWCNT. MWCNT. 43 43% UFRf 6 62. 11 1. 4

Abstract Wood is a common natural polymeric material with hydrophilicity and low biostability with a limited service life. The article considers the issue of using a multicomponent composition (used motor oil, rosin, paraffin) for impregnating birch wood and giving it increased water resistance, bio- and dimensional stability. The possibility of recycling the used impregnated wood to obtain a biochar adsorbent was shown. The impregnating composition was characterized by the FTIR method to assess the possibility of interaction between the functional groups of the impregnating composition and wood. Moisture and water absorption decreased by more than 4 and 6 times. Volumetric swelling decreased by 57% relative to untreated wood, the effectiveness against swelling after 30 days was 46%. The high efficiency of the impregnating composition against the wood biodegradation has been established. The method of micro-X-ray tomography determined a high degree of filling of the anatomical structures of wood. life oil rosin paraffin resistance bio stability shown times 57 3 46 46% established microXray micro X ray 5