Heat treatment is a promising and environment-friendly wood modification method. In the past several years, thermal modifications of wood have been widely used around the world for a broad range of applications such as flooring, decking, cladding, garden fences and furniture, etc. Oil heat treatment, as one of the heat treatment methods, can effectively improve the dimensional stability and biological durability of wood. Moreover, the mechanical properties of oil heat treated wood are a little better than that of modified wood in different gaseous atmospheres such as superheated vapor, nitrogen gas. Bamboo, with rich resources and excellent mechanical properties, is an important forest resource in China. However, in common with other biological materials, the main problem faced to bamboo and bamboo products is the susceptibility to attack by decay fungi, moulds and deformation. In this paper, no cooling (Ⅰ) and cooling to room temperature (Ⅱ) were individually conducted in the two different final step of oil heat treatment of bamboo at 180℃ for 2h. Contact angle measurements of bamboo before and after oil heat treatment showed a significant increase in bamboo hydrophobicity, and changes in the wettability of modified bamboo differed according to the different oil heat treatment process parameters. Results from scanning electron microscopy (SEM) and fourier transform infrared spectroscopy (FTIR) indicated that these phenomena may be due to the combination effect of the change of chemical composition and the surplus oil on the surface of modified bamboo. Due to a negative effect of the surplus oil on the bonding behavior of bamboo, a solvent extraction (100% ethanol) process was subsequently applied to extract the surplus oil of specimenⅠand specimenⅡ, and then specimen Ⅲ and specimen Ⅳ with a low oil content were obtained respectively. Finally, the bonding strength of bamboo laminated composites made by specimens Ⅲ and Ⅳ were tested and compared to control specimens.
Keywords: tree growing, dendroclimatology, technical wood properties
Authors
Li T.
College of Materials Science and Engineering, Nanjing Forestry University, Nanjing, China
Department of Civil and Architectural Engineering, Building Materials, Royal Institute of Technology, Stockholm, Sweden
Cheng D.L.
College of Materials Science and Engineering, Nanjing Forestry University, Nanjing, China
Wålinder M.E.P.
Department of Civil and Architectural Engineering, Building Materials, Royal Institute of Technology, Stockholm, Sweden
Zhou D.G.
College of Materials Science and Engineering, Nanjing Forestry University, Nanjing, China
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