Effects of Heat Treatment on Interfacial Properties of <i>Pinus Massoniana</i> Wood

• Main Authors: Zhigang Wu, Xue Deng, Lifen Li, Xuedong Xi, Meifen Tian, Liping Yu, Bengang Zhang
• Format: Article
• Language: English
• Published: MDPI AG 2021-05-01
• Series: Coatings
• Subjects: <i>Pinus massoniana</i> wood; heat treatment; interfacial properties; wettability; SEM
• Online Access: https://www.mdpi.com/2079-6412/11/5/543

Understanding the interfacial changes of wood during heat treatment can facilitate the improvement of the bonding and coating processes of heat-treated wood. Steam was used as the medium to modify <i>Pinus</i><i>massoniana</i> wood through heat treatment at 160, 180, 200, and 220 °C. Changes to the surface characteristics after heat treatment were characterized by Fourier transform-infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscope (SEM) and contact angle measurement. The results showed that: (1) hemicelluloses were the first to experience degradation at 160 °C, and this degradation was the most intense at 200 °C. The cellulose started experiencing obvious degradation at 200 °C, while there was less degradation of lignin at this temperature. (2) Oxygen-containing groups like hydroxyl and carbonyl were gradually reduced as temperature increased with deepened color and passivated surface. (3) Cellulose crystallinity presented a variable trend of increasing–decreasing–increasing. (4) Surface porosity and roughness of <i>Pinus massoniana</i> wood both increased after heat treatment. (5) The <i>Pinus massoniana</i> wood interface turned from hydrophilic to hydrophobic, and 180 °C was a turning point for the wettability of the <i>Pinus massoniana</i> wood interface.