纳米SiO_(2)/MUG复合改性剂的制备及其改性材性能研究

Properties of Poplar Wood Modified by Nano-SiO2/Melamine Urea Glucose Composite

为进一步提升三聚氰胺-尿素-葡萄糖(MUG)生物质树脂改性木材尺寸稳定性,采用单一或复合硅源[纳米SiO_(2)、KH550(K5)、KH560(K6)单一或复配后]与MUG生物质树脂复合,制得K5/MUG、K6/MUG、Si/MUG、Si/K5/MUG、Si/K6/MUG 5种有机-无机复合改性剂,分别浸渍处理人工林杨木,考察不同改性剂对杨木密度、吸水性、尺寸稳定性和力学强度等性能的影响,优选出性能最佳的复合改性剂,利用SEM和FTIR分析改性剂的分布及与木材组分的反应情况,探明复合硅协同效应及复合体系之间的相互作用机制。结果表明,5种复合改性剂均具有良好渗透性,改性材的吸药量均>200%、增重率均>44%,吸水性均比素材显著降低;其中,以5%质量分数的KH550、1%质量分数的纳米SiO_(2)和30%质量分数的MUG复合改性杨木的径向、弦向和体积湿胀率最低,分别为1.14%、2.13%和3.20%;增容率最小(8.1%);抗胀缩率最高(77.5%);顺纹抗压强度最高(130.9 MPa),较素材提高了92.03%。纳米SiO_(2)经KH550接枝改性后,能更均匀分散于MUG树脂中,并被树脂包覆固化于木材内,有机-无机协同效应使复合体系的交联程度提高,无机Si元素的刚性增加了木材机械支撑强度。因此,硅烷偶联剂改性纳米SiO_(2)能进一步提升MUG改性材的尺寸稳定性和力学强度等性能。

To further enhance the dimensional stability of modified wood with melamine-urea-glucose(MUG)biomass resin,single or compounded silicon sources,SiO_(2),KH550(K5)and KH560(K6)were mixed with MUG to prepare five organic-inorganic hybrid compound modifiers,i.e.,K5/MUG,K6/MUG,Si/MUG,Si/K5/MUG,and Si/K6/MUG,which were then used to modify poplar wood.The effects of different modifiers on the density,water absorption,dimensional stability and mechanical strength of poplar wood were investigated,and the best modifier was selected.SEM and FT-IR were used to analyze the distribution of modifiers and the reaction with wood components,and to investigate synergistic effect of organic and inorganic silicon and the interaction between modifier and wood.The results showed that all the compound modifiers had good permeability,with the absorption rate more than 200%,the weight gain was greater than 44%,and the water absorption rate was significantly lower than that of the untreated wood.Among the five compound modified woods,the Si/K5/MUG(5%KH550,1%nano-SiO_(2),and 30%MUG)modified wood had the lowest radial,tangential and volumetric swelling efficiency,which were 1.14%,2.13%and 3.20%,respectively.The bulking effect was the smallest as 8.1%,anti-swelling efficiency was the biggest as 77.5%,and the compression strength parallel to grain was the highest as 130.9 MPa,92.03%higher than that of the untreated wood.Nano-SiO_(2)can be more uniformly dispersed in MUG resin after being grafted and modified by KH550,and is coated and solidified in wood by resin.The organic-inorganic synergistic effect improves the cross-linking degree of the modifier and wood,and the rigidity of inorganic Si element increases the mechanical support strength of wood.Therefore,nano-SiO_(2)modified with organosilane can further improve the dimensional stability and mechanical strength of MUG modified wood.