Comparative analysis of inactivated wood surfaces : second place wood award

Šernek, Milan (author), Kamke, Frederick A. (author), Glasser, Wolfgang G. (author)

The changes in surface chemistry, wettability, and adhesion of inactivated wood surfaces, including yellow-poplar (Liriodendron tulipifera) and southern pine (Pinus taeda), were studied. Surface inactivation, which is induced by exposure to high temperature, causes poor adhesion. The comparative characterization of the surface was done by X-ray photoelectron spectroscopy (XPS), sessile drop wettability, and fracture toughness of adhesive bonds. Additionally, several chemical treatments were utilized to improve wettability and adhesion of inactivated wood surfaces. The results showed that wood drying caused modification in wood surface chemistry. The oxygen to carbon ratio (O/C) decreased and the C1/C2 ratio increased with drying temperature. A low O/C ratio and a high C1/C2 ratio reflected a high concentration of extractives and lignin on the wood surface. Contact angle decreased with time and increased with the temperature of exposure. A dependence of wood species was evident. The southern pine was most susceptible to inactivation particularly when bonded with PF adhesive. Yellow-poplar surfaces showed little inactivation when exposed to drying temperatures up to 187°C. The chemical treatments improved the wettability of inactivated wood surfaces, but an improvement in adhesion was not evident for specimens bonded with PVA. Sodium hydroxide (NaOH) was the most effective in restoring bonding ability of inactivated wood surfaces bonded with PF adhesive. The maximum strain energy release rate (Gmax) of specimens treated with NaOH increased by a factor of three when compared with inactivated specimens.

• Language: English
• Keywords: neaktivnost lesne površine, XPS, omočitev, adhezija, lomna mehanika, ekstraktivne snovi
• Work type: Not categorized
• Typology: 1.12 - Published Scientific Conference Contribution Abstract
• Organization: BF - Biotechnical Faculty
• Year: 2002
• Number of pages: Str. 32
• PID: 20.500.12556/RUL-36421
• UDC: 674
• COBISS.SI-ID: 895881
• Publication date in RUL: 10.07.2015