WOOD RESEARCH Volume 64, Number 6, 2019
Zhigang Wu, Sicheng Chen, Meifen Tian, LIFEN LI, Liping Yu, Xuedong Xi, Jiankun Liang, Bengang Zhang, Hong Lei, Jun Zhang, and Taian Chen

Effects of heat-treatment on bonding performance of Betula alnoides

Heat-treatment woods of Betula alnoides were prepared by using vapor as the heat-conducting medium. Effects of heat-treatment time and heat-treatment temperature on equilibrium moisture content, density, pH value, contact angle and bonding performance of Betula alnoides were discussed in this paper. The results indicated that: (1) With the increase of heat-treatment temperature, the equilibrium moisture content, density and pH value of Betula alnoides decreased gradually. (2) With the increase of heat-treatment temperature, the contact angle of Betula alnoides increased from 70.08° to about 100°, resulting in the reduction of bonding strength gradually. Bonding strength of Betula alnoides after heat-treatment was related with the used adhesive. Bonding strength of different adhesives decreased to different extents. The bonding strength of Betula alnoides wood with polyvinyl acetate (PVAC) resin was generally higher than that of melamine-urea-formaldehyde (MUF) resin. The former were 6.35-4.56 MPa, and the latter were 5.60-3.00 MPa. (3) Heat-treatment time influenced equilibrium moisture content, density, contact angle, pH value and bonding strength of Betula alnoides less than heat-treatment temperature. (4) Heat-treatment could affect strength and surface performance of Betula alnoides greatly and the processing medium should be extended.

WOOD RESEARCH Volume 66, Number 1, 2021
Zhipeng Zhu, Dengyun Tu, Ziwei Chen, Chuanfu Chen, and Qiangfang Zhou

Effect of hot pressing modification on surface properties of rubberwood (Hevea brasiliensis)

This research aims to investigate the effect of thermal modification by hot pressing on surface characteristics of rubberwood. For this purpose, rubberwood specimens were thermally modified by hot pressing in an open system at three different temperatures (170, 185, and 200°C) for two different durations (1.5 or 3 h). Based on the results, the values of chromatic aberration (ΔE), contact angle and glossiness increased, and roughness decreased with increasing temperature and enlarging duration further. Although the contact angle had increased, it was still less than 90°. This aesthetic surface of rubberwood could be retained by using transparent organic coatings. The thermally modified rubberwood with excellent performance could be used as a material for solid wood flooring, wallboard, and furniture applications.