Wettability of oil heat-treated bamboo and bonding strength of laminated bamboo board

• Bamboo sheets were heat-treated in soybean oil.
• The surplus oil in the modified bamboo was extracted with ethanol.
• The effect of oil heat treatment on the microstructure and chemical component of bamboo were investigated by SEM and FTIR.
• The wettability of modified bamboo was evaluated with the sessile drop technique.
• The bonding strength of laminated bamboo board varied with heat treatment conditions.

In order to improve the interface properties of bamboo in laminated board applications for severe outdoor environment, bamboo sheets were heat treated in soybean oil and post oil extracted in this paper. Following oil heat treatment at 180 °C for 2 h, bamboo specimens were either removed from the oil immediately or left in the oil until they were cooled to room temperature. Contact angle measurements before and after oil heat treatment showed a significant increase in the hydrophobicity of bamboo, and these changes differed based on the process parameters. Results from scanning electron microscopy and Fourier transform infrared spectroscopy 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. Then, the ethanol extraction process was subsequently applied to remove the surplus oil. Finally, the results of bonding strength tests on laminated bamboo boards prepared from oil heat-treated samples which thereafter had been subjected to ethanol extraction showed acceptable interface properties, although lower than the reference.