Shear bond strength of black locust wood glued with three adhesive systems

Black locust wood was bonded with three commercial adhesives (PVAc, PU, epoxy) and tested for its shear bond strength against process (treatments I and II) and surface parameters (radial, tangential, roughness). For treatment I (applied pressure 8 bar, press time 1.5 h, curing time 24 h), the mean shear bond strength was found to be 6.95 N.mm -2, 5.54 N.mm -2 and 10.53 N.mm -2 corresponding to the three adhesives tested, respectively. Increase in press and curing time in treatment II (press time 3 h, curing time 7 days) significantly improved the gluing performance of adhesives, 9.58 N.mm -2 for PVAc, 13.32 N.mm -2 for PU and 15.03 N.mm -2 for epoxy. Surface of gluing (radial, tangential) did not affect the shear bond strength significantly. Failure within wood was found to be up to 40% for treatment I (PVAc, epoxy) and up to 85% for treatment II (epoxy). Positive linear regressions were calculated between shear bond strength and wood failure only for PU and epoxy adhesives. Shear bond strength was not related to surface roughness for any adhesive.