Properties and bonding interface characteristics of an innovative bamboo flattening and grooving unit (BFGU) for laminated bamboo lumber

The challenges in manufacturing laminated bamboo lumber are standardization and surface bonding optimization. This study proposes an innovative bamboo flattening and grooving unit (BFGU) to complete the issue. Through the flattening and grooving treatment of bamboo, the porous structure of the bamboo surface is formed and normalized simultaneously. After treatment, the bonding area of the unit is 8.13 % higher than that of the planing unit, and the material utilization can reach 64 %. The highest MOE and MOR of the laminated bamboo lumber prepared by the unit is 9648.32 MPa and 123.73 MPa, respectively. In addition, the grooving of the unit makes the laminated bamboo lumber still have a specific load-bearing capacity after reaching peak strength. At the same time, more parenchyma cells are exposed at the bonding interface after treatment, which is beneficial for the glue to infiltrate the bamboo and form the physical bonding force under the action of cross-linking network. In addition, these parenchyma cells are also more likely to combine with glue to form the chemical force. The BFGU can develop a robust gluing ability, fully meeting the needs of preparing laminated bamboo lumber.