Thermochemical modification of beech wood with ammonium hydroxide

Abstract Four variants of the thermochemical modification were conducted on beech wood at a temperature 130 °C, employing NH 4 OH concentrations 5% or 10% for durations either 12 24 h. The weight% gain (WPG) and bulking coefficient (BC) initially calculated. Subsequently, wood’s degree discoloration was assessed using CIELAB-colour-system. Chemical structure alterations determined through Fourier transform infrared spectroscopy (FTIR), while compressive strength parallel to grain measured. As concentration increased treatment duration extended, samples displayed simultaneous weight increase volume reduction. Δ E * values ranged from 19.33 21.09 units, indicating significant color alteration. FTIR analysis revealed differences between spectra unmodified control sample OH-treated samples. reduced in hydroxyl carboxyl groups within main side chains hemicelluloses. Additionally, decrease absorption peak intensity unconjugated carbonyl group 1740 cm − 1 indicated relative reduction hemicellulose content. Compressive tests showed that improved modulus elasticity, increasing it 10,898 MPa (in sample) range 11,663 13,390 MPa. Similarly, 77.10 81.56-107.19 Interestingly, this improvement more pronounced with higher prolonged durations.