关键词: 热处理, 疏解竹单板, 竹基纤维复合材料, 耐水性能, 力学性能

Abstract: [Objective] The defibering bamboo veneer were treated by hot dry air under different temperature, and then were used to manufacture the bamboo-based fiber composites. The physical and chemical properties of defibering bamboo veneer were evaluated, the physical and mechanical performance of bamboo-based fiber composites were also studied, with the aim to provide the theory basis for optimization manufacturing process and new product development.[Method] Previous research about heat treatment mainly focus on bamboo split and bamboo stick, there are few reports on the properties of defibering bamboo veneer under high temperature heat treatment. In this study, the defibering bamboo veneer were heat-treated at 180 and 200℃ for 4 h, and the heat-treated defibering bamboo veneer were used to manufacture the bamboo-based fiber composites, the performance of the heat-treated defibering bamboo veneer and bamboo-based fiber composites were evaluated.[Result] Compare with 180℃ treatment, the mass loss of 200℃ treated specimens increased by 143%. Compared with the untreated defibering bamboo veneer, the holocellulose and α-cellulose of heat-treated samples were reduced by 11.36%, 20.15% and 21.95%, 35.94% respectively, the corresponding lignin relative content increased by 16.36% and 43.56%. The degradation product of hemicellulose reduced the pH value and buffering capacity. FTIR and XPS analysis showed that after heat treatment, the surface hydroxyl number were reduced which decreased the water absorbing capacity of heat-treated defibering bamboo veneer. After heat treatment, the color of defibering bamboo veneer and bamboo-based fiber composites was darkened obviously, the width swelling, water absorption and thickness swelling were reduced by 11.20%, 15.88%, 7.03% for 180℃ and 21.60%, 32.27%, 26.60% for 200℃ respectively, and the water resistance were improved distinctively. The modulus of rupture and horizontal shear strength were reduced by 39.07%, 33.51% for 180℃ and 56.14%, 42.15% for 200℃ respectively, the modulus of elasticity was affected slightly.[Conclusion] With the increase of heat treatment temperature, the extract volatile and degradation of chemical composition, which the causes increase of mass loss and relative content of lignin, the decrease of pH and buffer capacity and the content of holocellulose and α-cellulose, reduced the water absorbing capacity of heat-treated defibering bamboo veneer. The surface color of defibering bamboo veneer and bamboo-based fiber composites was darkened obviously, the water resistance were improved distinctively, the modulus of rupture and horizontal shear strength were reduced dramatically, and the modulus of elasticity was affected slightly.

Key words: heat-treated, defibering bamboo veneer, bamboo-based fiber composites, water resistance, mechanical property