Effect of Bamboo Culm Grading on the Properties of Flattened Bamboo Boards

Abstract

As a natural biomass material, bamboo is subject to variations in culm size as well as in physical and mechanical properties that substantially influence processing and product quality. The diameter, thickness, and hardness of bamboo culms are critical factors for the output and quality of flattened bamboo board (FBB). In this study, the effects of different hardness modulus (HM) grades on the physical and mechanical properties of FBB were examined. The results showed that the HM of Moso bamboo (Phyllostachys pubescens) followed a normal distribution. Nine grades of HM could be divided by an interval of 5 KN/mm2. The physical and mechanical properties of FBB were positively correlated with the HM of bamboo culms. Compressive strength, tensile strength, and shear strength, as well as the bending properties of FBB, each increased with increasing HM. Furthermore, under the same conditions, the mechanical properties of FBB were superior to those of both bamboo strips and bamboo culms. The softening, flattening, and planing processes were beneficial in improving the performance of bamboo. The strong correlation between HM and the properties of FBB indicates that the HM grading of bamboo culms can be used in bamboo processing to produce high-quality FBB products with uniform performance.