Optimization of spruce (Picea abies L.) wood thermal treatment temperature to improve its acoustic properties

The study was undertaken to establish the thermal treatment parameters of spruce (Picea abies L.) wood that would ensure the highest possible value of the specific modulus of elasticity (E/ρ) and, thus, the best acoustic performance. The basic acoustic parameters of spruce wood were determined prior to and after its thermal treatment. As a result of thermal treatment, the samples density slightly decreased by about 1%, irrespective of temperature applied. The average value of Young modulus of the samples after modification at 120 to 160 °C increased from 10.1 to 10.7 GPa (6%). The specific modulus of elasticity increased on average by 6.5%. Increase of the modification temperature to 180 °C resulted in decreasing of the values of mechanical parameters by over 4%.