Microscopic Characterization of Modified Phenol- Formaldehyde Resin Penetration of Bamboo Surfaces and its Effect on Some Properties of Two-Ply Bamboo Bonding Interface

The bonding interface between bamboo elements and adhesives is presumed to be significantly influenced by the degree of adhesive penetration into the porous network of interconnected cells of bamboo surfaces. In the study presented here, the average depth and effective depth of phenol-formaldehyde resin (PF) modified by different contents of lower-molecular weight (LMW) PF on bamboo surface were evaluated, making use of fluorescent microscopy characterization. The shear distribution at the bonding interface was measured by means of electronic speckle pattern interferometry (ESPI), along with tensile strength measurements, to determine the shear strain distribution on a macroscopic scale. This research combined macroscopic mechanical properties with microscopic interfacial mechanical properties, and it was found that PF modified with 10% LMW PF performed better than other modified PF. Moreover, it was assumed that the results of this study would influence the choice of bamboo-specific adhesives under different strain conditions.