Effect of removing extent of bamboo green on physical and mechanical properties of laminated bamboo-bundle veneer lumber (BLVL)

This study employed the process of removing bamboo green and bamboo brooming from Neosinocalamus affinis in the production of laminated bamboo-bundle veneer lumber (BLVL) with a thickness of 28 mm. The effect of the removing extent of bamboo green on dimensional stability, modulus of rupture, modulus of elasticity and horizontal shearing strength of BLVL was discussed. The results show a rising trend for the lightness (L*) as well as red hue (a*) and yellow hue (b*) with increasing extent of removing bamboo green, The higher the extent of removing bamboo green, the less wax and SiO2 remained on the bamboo surface, the smaller the contact angle of bamboo-bundle and the better the dimensional stability of the corresponding BLVL. As the removing extent of bamboo green increased, BLVL exhibited a slightly decreasing value of modulus of rupture, modulus of elasticity and horizontal shear strength prior to the 28 h cycling treatment, while less strength reduction was observed after the treatment. The ones without removal of bamboo green suffered most severe strength reduction. In terms of horizontal shearing strength, A, B, C, D could meet the standard requirement of GB/T 20241-2006, while A, B and C, except for D, could reach the 9 V-12H level according to Bamboo Scrimber standard.