Study on interface bonding and mechanical properties of arc-shaped bamboo-poplar wood composites

The bamboo-wood composite is a high-performance product that utilizing the strengths of both materials, which also can effectively reduce the weight of the composite material. An equal arc-shaped bamboo split has been studied by our research group, which retains the natural arcuate structure and achieves a utilization rate of approximately 85 %. Based on this, a new composite made of arc-shaped bamboo split and poplar wood is prepared in this paper. And another material made of flattened bamboo and poplar wood also prepared as a control. The mean flexural modulus and strengths for arc-shaped bamboo split were 12,179.33 MPa and 195.77 MPa respectively, the shear strength of the adhesive layer in the composite of arc-shaped bamboo and poplar wood was a robust 8.02 MPa. The flexural maximum load of arc-shaped bamboo-poplar composite was 9896.29 N, nearly twice as much as that of flattened bamboo-poplar composite, whose excellent performance was expected to exceed the requirements of industrial products. The phenol-formaldehyde (PF) adhesive penetrated into the bamboo and wood quite deeply, allowing it to secure the two pieces of board together like many small glue nails. Besides the physical connections, lots of effective chemical bonding were formed between PF and the two boards. In addition, it was also found that the fracture mode of arc-shaped bamboo and poplar wood composites was ductile fracture, which was different from the brittle fracture mode of traditional bamboo and wood composites. Overall, this new arc structural composite material has high performance and will expand the application of bamboo engineering materials in industry products.