Using Non-Destructive Testing to Determine the Correlation between Dynamic Mechanical Properties and Bonding Strength of Wood-Plastic Composite Adhesive Joints

Wood-plastic composites (WPC) have been developed into new and important wood-based composites because of their benefits for the environment, economy, and recyclability. When combined with structural adhesives, WPCs will have a greatly broadened application in the construction field. In this work, epoxy resin and acrylic ester were used to bond WPC adhesive joints. The shear strength of the adhesive joints was determined and investigated. Resonant frequency and dynamic modulus of elasticity (MOE) of the WPC adhesive joints were measured using the longitudinal vibration method. The correlation between different vibration parameters and shear strength of WPC adhesive joints was also investigated. Results showed that the epoxy resin had a better bonding quality than the acrylic ester on the bonding of WPC adhesive joints. The resonant frequency, dynamic MOE, and the dynamic MOE ratio of the WPC adhesive joints had close correlations with their shear strength for the samples bonded with epoxy resin.