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摘要: 采用红外吸收光谱法、热分析法探讨在热压过程中毛竹Phyllostachys edulis材加工剩余物蒸爆纤维木质素(SEBPL)结构变化规律,为确定热压工艺及研究无胶黏结机制提供理论依据。①竹材加工剩余物蒸爆纤维木质素高于竹粉磨木木质素(MBL)。竹无胶纤维板木质素(SEBBL)低于SEBPL,表明部分低分子量的木质素在热压过程中形成木质素-木质素聚合物或木质素-多糖复合体(LCC)。②SEBPL保留了木质素芳香环的结构特征,但蒸爆过程中木质素侧链的酯键、醚键断裂,形成游离的酚羟基,使蒸爆纤维木质素游离酚羟基含量增加。③SEBBL分别在115 ℃和200 ℃附近有2个玻璃态转化的吸热峰。在200 ℃吸热峰可能源于在热压过程形成的木质素-木质素聚合物或木质素-多糖复合体。④蒸爆处理时间长,竹无胶纤维板的静曲强度和弹性模量降低,而内结合强度有所提高。竹材加工剩余物蒸爆纤维制备的无胶纤维板具有良好的尺寸稳定性。图5表1参15Abstract: bamboo (Phyllostachys edulis) residue was subjected to steam explosion treatment to produce superior fibers for binderless boards. Then,lignin was isolated from extract-free bamboo meal,steam exploded pulp,and binderless boards with characteristics being determined by thermo-gravimetry (TG),differential scanning calorimetry (DSC),and fourier transform infrared spectroscopy (FTIR). Results showed that (1) yields of lignin directly extracted with dioxane-water from steam exploded bamboo pulp (SEBPL) and binderless board (SEBBL) were higher than that of milled bamboo lignin (MBL). Also,yield of sebbl was lower than SEBPL. (2) FTIR results showed cleavage of ester and ether bonds between lignin and p-coumaric acid during steam explosion treatment. (3) SEBBL showed two glass transitions at 115 ℃ and 200 ℃,while MBL gave one glass transitions at 155 ℃. (4) the modulus of rupture (MOR) and modulus of elasticity (MOE) decreased with an increase in steaming time; whereas internal bonding (IB) increased. In all cases the dimensional stability of boards did not exceed the maximum requirements for type GB/T 11718-1999.[Ch,5 fig. 1 tab. 15 ref.]
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https://zlxb.zafu.edu.cn/article/doi/10.11833/j.issn.2095-0756.2012.03.015
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