Suitability of thermally modified wood for binderless particleboard production: Effects of temperature and moisture content in hot pressing

The use of thermally modified wood has grown significantly worldwide over the past 20 years owing to its natural, chemical-free properties, enhanced dimensional stability, and improved biological durability. The binderless particleboard (BP) production process offers an effective way to recycle waste from thermally modified wood. In this study, Fourier-transform infrared (FTIR) spectroscopy and modulated temperature technology were employed to investigate the chemical changes in thermally modified wood as a function of temperature. The impact of moisture content (MC) and temperature on the compression characteristics of particleboards was also examined. The resulting particleboards were subjected to tests for thickness swell and structural morphology (SEM) and vertical density profile analyses. The particleboards produced from thermally modified wood with an MC of 20 % and at a hot-pressing temperature of 170 °C exhibited superior properties to those produced at 8 % MC and 150 and 190 °C. This superior performance can be attributed to the chemical changes in wood, particle size, and the heat transfer and conductivity of the particleboards at high temperature and MC, which renders them more malleable during hot pressing. The particleboards manufactured at 20 % MC and at a hot-pressing temperature of 170 °C demonstrated an internal bonding (IB) of 0.77 MPa, a thickness swell (TS) of 8.14 %, and a homogeneous density distribution. The study provides valuable insights into the production of particleboards from thermally modified wood by optimising the MC and temperature conditions for hot pressing. This research offers a sustainable approach to reusing thermally modified wood waste and promotes the development of more efficient particleboard production processes. Future research could focus on broadening the application scope and exploring the long-term durability and performance of the particleboards produced under the identified optimal conditions.