【摘要】 以脱脂大豆粉为原料制备大豆蛋白基胶黏剂（豆胶,S）,以普通甲醛制备的酚醛树脂（PF₁）和高浓度甲醛制备的酚醛树脂（PF₂）为交联剂,使用前将两者直接混合得酚醛树脂改性豆胶（PF₁/S、PF₂/S）。利用差示扫描量热（DSC）、红外光谱（FT-IR）、动态热机械性能（DMA）和核磁共振碳谱(¹³ C NMR)分析对产品性能进行了测试与表征。结果表明:等物质的量之比条件下,高浓度甲醛较之普通甲醛制备的酚醛树脂改性豆胶胶合板干、湿剪切强度分别提高4.3%和11.6%,并且强度稳定性好;动态DSC分析表明,PF₂可以降低豆胶体系的固化温度和活化能,与豆胶的交联反应较容易;¹³ C NMR分析表明,PF₂体系羟甲基达88.73%,明显高于PF₁的80.91%;FT-IR分析证实酚醛树脂与豆胶中的氨基发生反应,并且PF₂反应效率更高;DMA分析表明,PF₂/S能够改善胶合产品的力学性能和热稳定性,降低豆胶的固化反应起始温度,提高固化反应速率。更多还原

【Abstract】 Soy-based adhesive（ S） was prepared by use of defatted soy flour as feedstock,and new phenol formaldehyde resins were synthesized by using common formaldehyde and high concentration formaldehyde（ PF₁,PF₂） as crosslinker agent. S and PF₁,or PF₂ were then directly blended to form the modified S. The structure and the performance of these adhesives were subsequently characterized by differential scanning calorimetry（ DSC）,infrared spectrum（ FT-IR）,dynamic thermal mechanical properties（ DMA） and nuclear magnetic resonance(¹³ C NMR),respectively. It was found that with the same molar ratio,plywood of S crosslined by PF₂ showed better bonding performance and strength stability. Their dry and wet strengths increased by nearly4. 3% and 11. 6% compared with those crosslined by PF₁,respectively. Dynamic DSC analysis showed that PF₂ was easy to react with S by decreasing the activation energy of adhesives system.¹³ C NMR showed that the hydroxymethyl content PF₂ system was88. 73%,which was significantly higher than the 80. 91% of PF₁. FT-IR analysis confirmed that the phenol formaldehyde resin reacted with amino of S,and PF₂ showed much more efficient than PF₁. The DMA results showed that PF₂ could improve the mechanical performance and thermal stability of the final product,reduce the onset curing temperature and curing temperature,and accelerate the curing reaction rate of modified S.更多还原