Effect of microwave-assisted curing on bamboo glue strength: Bonded by thermosetting phenolic resin

Abstract

In this study, bamboo strips was glued by thermosetting phenolic resin which was cured by microwave, and the effect of microwave-assisted curing on bamboo glue strength was also researched. Fourier transform infrared spectroscopy (FT-IR) was used to evaluate curing degree of phenolic resin and bamboo bonding strength was characterized by compression shear test. Scanning Electron Microscopy (SEM) and Atomic Force Microscope (AFM) were employed to observe the morphology of cured phenolic resin and glued bamboo. Curing degree results showed that microwave was a fast and efficient curing method, which could reduce curing time by 50%. Bamboo compression shear strength results indicated that the sample cured at 100°C for 10min would reach its optimum mechanical performance. Higher curing temperature (110°C) caused carbonization in bamboo, which would weaken mechanical strength of bamboos. The SEM image indicated that fast curing by microwave would cause expansion of phenolic resin, which would cause rough surface and increase the bonding strength of bamboo and phenolic resin. Furthermore, during the rapid curing process, phenolic resin embedded in the pores on bamboo surface, which would reduce defects on the interface between bamboo and resin. Thus shear strength of microwave cured bamboo was much higher than that of bamboo cured by thermal.