Effects of secondary bonding process parameters on the bonding and mechanical properties of bamboo scrimber composite: Glue type, spread rate and pressure

Abstract

Bamboo scrimber composite (BSC), which demonstrates huge potential in construction applications is a novel composite material prepared from bamboo and phenolic resin. The aim of this study was to address the issue regarding the size of BSCs via a secondary bonding mechanism. In this work, the effects of glue type, spread rate and pressure on the bonding and mechanical properties of secondary bonding-bamboo scrimber composites (S-BSCs) were investigated. The bonding properties were tested through shear and delamination tests, and the mechanical properties were characterized by modulus of rupture (MOR), modulus of elasticity (MOE) and compressive strength(CS). The results of the study revealed that the bonding properties of S-BSCs were optimized when Phenol-Resorcinol-Formaldehyde resin (PRF) was used as the glue, at a spread rate and pressure of 275–300 g/cm2 and 1.2 MPa, respectively. The highest shear strength and wood failure percentage, as well as the lowest boiling delamination rates for two cycles were achieved at a PRF spread rate of around 275–300 g/cm2, under a pressure of 1.0 MPa. which were 24.84 MPa, 90.19%, 0% and 0.77% respectively. On the other hand, the lowest boiling delamination rates of 0.23% and 0.89% for two cycles, respectively were found at a PRF spread rate of 225–250 g/cm2 under a pressure of 1.2 MPa. The study revealed that the values of the MOR and MOE, as well as of CS for the S-BSCs were comparable with those of the BSC samples (146.98 MPa, 14.92 GPa, 125.49 MPa) in the pressure ranges of 144.73–148.10 MPa, 13.77–15.05 GPa, and 120.61–125.86 MPa, respectively. Also, it was found that the mechanical properties of S-BSCs were independent of the type of glue, spread rate, and pressure. Overall, this study determined the effect of secondary bonding process on the bonding and mechanical properties of BSCs.