Fig. 5: Bonding performance of the wood assemblies.

a Photograph of the tensile shear test setup for the lap-joint wood specimens. b Representative stress-strain curves of tensile shear test of the wood samples bonded with different cellulose-ILs, using hot pressing in the presence of non-regenerated MCC (orange), and that of solid wood (purple). c A photograph of the fractured samples after the tensile shear test. d SEM micrographs of the fractured surfaces in bonded wood samples. White arrows indicate the location of the bonding interface. e A compilation figure showing the shear strength as a function of density for various wood adherends. The properties of solid wood, adhesive-bonded wood, friction-welded wood are shown as black rhombus, beige circles, and dark red circles, respectively. The values obtained in this work are shown with green stars. The detailed information is listed in Supplementary Table 3. f Photo of boiling test of the pulp-bonded wood and the mean dry shear strength of the bonding line before (n = 10, green dots) and after (n = 5, light green dots) boiling test. g Photographs of cross sections of 3-layer plywood specimens of birch veneers bonded with pulp-IL (green) and commercial phenol formaldehyde resin (dark yellow), along with their shear strength. Data are presented as mean ± standard deviation (s.d.) of n = 4 replicates.