Quality control of vacuum thermally modified wood with near infrared spectroscopy

• Further optimization of the vacuum thermal treatment procedure at industrial scale is possible.
• Potential of NIR spectroscopy as a product quality assessment tool was confirmed.
• RPD values indicate that high quality chemometric models were obtained for soft- and hardwoods.

The thermo-vacuum process is an alternative technology for thermal modification of wood where reduction of oxygen concentration inside the reactor, necessary to avoid wood combustion, is obtained by applying vacuum. The goal of this research was to exploit the potential of near infrared spectroscopy for the quality control of TMW (prediction of mass loss and equilibrium moisture content in both softwoods and hardwoods), exposed to the thermal treatment in vacuum conditions. Applied chemometric techniques confirm great potentiality of the near infrared spectroscopy. Important parameters characterizing quality of TMW in vacuum conditions were predicted with high accuracy. Prediction errors of chemometric models based on near infrared spectra were relatively small; 0.9% and 0.36% in case of mass loss and equilibrium moisture content respectively. Such methodology might be helpful for development of on-line process control and for further optimization of the thermal treatment procedure at industrial scale.