低共熔溶剂预处理对表面矿化木材性能的影响

Effects of deep eutectic solvents pretreatment on performance of surface mineralized wood

【目的】为了解决木材矿化改性渗透难、矿化位点少等问题,本研究采用低共熔溶剂(DES)预处理速生杨木、打开木材渗透通道、构建活性位点,研究低共熔溶剂预处理对表面矿化木材性能的影响。【方法】本研究使用DES预处理杨木构建矿化位点,诱导SiO_(2)在木材表面实现原位矿化,再通过热压制备表面矿化木材,分析DES预处理对表面矿化木材物理力学性能的影响作用;以较优条件制备表面矿化木材,并分析其微观结构形貌和热性能。【结果】(1)表面矿化木材的密度、质量增长率和表面硬度均随DES预处理时间的增加呈先上升后下降的趋势;预处理为2 h时,较未处理材分别提高了35.25%、16.35%和51.53%;表面矿化木材的疏水性大幅提高,预处理0.5 h时初始接触角增大了74.08%。(2)DES预处理可以显著改善表面矿化木材力学性能;当DES预处理时间为2 h时,表面矿化木材的抗弯强度和弹性模量分别提升了20.53%和214.55%。(3)表面矿化处理向木材内引入SiO2形成有机–无机杂化结构,提高木材阻燃性能;DES预处理2 h时,表面矿化木材的质量残余率相较于未处理材提高了70.81%,热释放速率降低了69.9 kW/m^(2),总热释放量降低了27.3 MJ/m^(2)。【结论】速生杨木经DES预处理和表面矿化联合改性后物理力学性能提升,热稳定性和阻燃性能良好。

[Objective]In order to solve the problems of difficult penetration and less mineralization sites in wood mineralization modification,deep eutectic solvent(DES)pretreatment was used to open the penetration channel and construct active sites of fast-growing poplar,and the effects of DES pretreatment on the properties of surface mineralized wood were studied.[Method]Poplar wood was pretreated with DES to construct mineralization sites,and SiO_(2) was induced to realize in-situ mineralization on the wood surface.Then surface mineralized wood was prepared by hot pressing.The effects of DES pretreatment on physical and mechanical properties of surface mineralized wood were analyzed.Surface-mineralized wood was prepared under optimal conditions,and its microstructure morphology and thermal properties were analyzed.[Result](1)The density,mass gain rate and surface hardness of surface mineralized wood increased at first and then decreased with the increase of DES pretreatment time,and increased by 35.25%,16.35%and 51.53%,respectively when pretreated for 2 h compared with untreated wood.The hydrophobicity of surface mineralized wood was greatly improved,and the initial contact angle increased by 74.08%after 0.5 h pretreatment.(2)DES pretreatment can significantly improve the mechanical properties of surface mineralized wood.When DES pretreatment time was 2 h,the modulus of rupture and elasticity of surface mineralized wood increased by 20.53%and 214.55%,respectively.(3)The surface mineralization treatment introduced SiO2 into the wood to form an organic-inorganic hybrid structure,which improved the fire resistance of wood.When the surface mineralized wood was pretreated for 2 h,the mass residual ratio of the surface mineralized wood increased by 70.81%compared with the untreated wood,and the heat release rate reduced by 69.9 kW/m^(2),and the total heat release reduced by 27.3 MJ/m^(2).[Conclusion]After DES pretreatment and surface mineralization,the physical and mechanical properties of fast-growing poplar are improved,and the thermal stability and fire resistant properties are good.