| 摘要: |
| 【目的】通过优化葡萄糖/三聚氰胺/尿素树脂（MUG）的葡萄糖配比及MUG树脂与硅酸钠的配比，减少二氧化硅及葡萄糖羟基残留，以改善改性材吸湿、尺寸不稳定等问题。【方法】设置葡萄糖、三聚氰胺、尿素物质的量比为m∶1∶4（m分别为2，4，6，8，10和12），根据红外解析树脂预聚程度，测定树脂黏度、固含量和水溶倍数等性能，筛选出优化MUG树脂的葡萄糖配比；将优化制备的MUG树脂与硅酸钠复配得5种改性剂：G5S25、G10S20、G15S15、G20S10、G25S5G代表MUG树脂，S代表硅酸钠，下标数值代表其在改性剂中的质量分数），通过测定改性材黏度、pH值和改性材的密度、增重率、吸水率、尺寸稳定性、力学性能，优化MUG树脂与硅酸钠的复合配比。【结果】①随着葡萄糖增加，MUG树脂的黏度、固含量增大，水溶性好，储存更稳定。②红外分析表明，随着葡萄糖增加，MUG树脂在1 667 cm-1处的酰胺羰基峰、在1 630 cm-1处的酰胺N—H键弯曲振动峰均变小，在1 552和1 421 cm-1处的亚氨基树脂特征峰、在770 cm-1处的呋喃环特征峰均增强；当葡萄糖物质的量比增大至8以上时，上述吸收峰强度无明显变化，故葡萄糖物质的量比宜为8。③随着树脂含量增加，MUG树脂/硅酸钠改性剂的黏度增大、pH值降低，G25S5改性剂不稳定、易产生沉淀。④各组改性材中，以G20S10改性材的增重率最大、吸水率最低，径向、弦向、体积湿胀率最低；与素材相比，其密度提高了60.9%，浸水144 h时的吸水率下降35.4%；其径向、弦向、体积抗湿胀率分别为60.81%，34.20%和51.87%，抗弯弹性模量、抗弯强度和顺纹抗压强度均比素材明显提高。【结论】MUG树脂能有效抑制硅酸钠引起的吸湿和皱缩，二者的优化复配比例为质量分数20%树脂和质量分数10%硅酸钠。 |
| 关键词: 人工林杨木；木材改性剂 葡萄糖/三聚氰胺/尿素生物质树脂；改性材性能 |
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| 基金项目:中国林业科学研究院中央级公益性科研院所基本科研业务费专项资金项目（CAFYBB2020ZC003） |
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| Optimized preparation of MUG resin and sodium silicate modified poplar wood |
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DU Haojia,Lu Wenhua,KONG Jing,et al
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| Abstract: |
| 【Objective】This study reduced the residues of silica and glucose hydroxyl groups by optimizing glucose ratio of glucose/melamine/urea (MUG) resin to solve the problems of moisture absorption and dimensional instability.【Method】In this paper,the ratio n (glucose)∶n (melamine)∶n (urea) was set as m∶1∶4 with m values of 2,4,6,8,10 and 12,respectively.According to the infrared analysis of the prepolymerization degree,the properties including resin viscosity,solid content and water solubility were determined to obtain the optimized MUG resin.Then,five modifiers of G5S25,G10S20,G15S15,G20S10 and G25S5 were obtained by compounding the optimized MUG resin with sodium silicate (G represents MUG resin,S represents sodium silicate,the subscript represents the mass ratio).The density,water absorption,dimensional stability and mechanical properties of the modifiers were analyzed to optimize ratios of MUG resin and silicon.【Result】①With the increase of glucose,viscosity and solid content of MUG resin increased,and MUG resin had good water solubility and stable storage.②Infrared analysis showed that with the increase of glucose,the amide carbonyl peak at 1 667 cm-1 and bending vibration peak of amide N—H bond at 1 630 cm-1 of MUG resin decreased,while the characteristic peaks of imino resin at 1 552 cm-1 and 1 421 cm-1 and furan ring at 770 cm-1 increased.As above absorption peaks had no changes in intensity when the amount of glucose substances was above 8,the proper amount of glucose substances was determined as 8.③With the increase of resin content,the viscosity of MUG resin and sodium silicate modifiers increased and the pH values decreased.The G25S5 modifier was unstable and easy to precipitate.④G20S10 had the largest increase of wood density by 60.9%,the lowest water absorption decrease by 35.4% 144 h after soaking,and the lowest radial,tangential and volume swelling shrinkage resistances of 60.81%,34.20%,and 51.87%,respectively.The flexural modulus of elasticity,flexural strength and compressive strength were also higher than natural wood.【Conclusion】MUG resin can effectively inhibit wood moisture absorption and shrinkage caused by sodium silicate,and the optimum mass ratios were 20% MUG and 10% sodium silicate. |
| Key words: plantation poplar wood modifier glucose-melamine-urea resin properties of modified wood |
