乙酸酐对大豆基木材胶粘剂的改性研究

用乙酸酐改性大豆基木材胶粘剂,研究了乙酸酐为不同浓度时,双因素(pH值和温度)对耐水胶合强度的影响。试验结果得到4个不同浓度下pH值和温度的最佳组合值为:乙酸酐体积分数为1.2%、1.8%、2.4%、3.0%时对应的pH值/温度是8/55℃、8/55℃、7/70℃、7/70℃,最佳耐水胶合强度可提高到0.72 MPa。以乙酸酐体积分数为1.8%为例,采用茚三酮法测得大豆蛋白质的酰化程度,分析不同温度下pH值对酰化程度的影响,结果显示:耐水胶合强度与酰化程度不成正相关。由红外光谱分析可知,乙酸酐与大豆蛋白的游离氨基发生了交联反应,从而提高了大豆基木材胶粘剂的耐水胶合强度。

Modification of acetic anhydride on soy-based wood adhesive properties

Acetic anhydride was used to modify soy-based adhesives.Effects of temperature and pH value on hydrophobic strength were investigated under different acetic anhydride concentrations.The results obtained the best constituted values including temperature and pH under 4 different acetic anhydride concentrations.The pH value to temperature corresponding to acetic anhydride volume fraction(1.2%、1.8%、2.4%、3.0%) were 8/55℃、8/55℃、7/70℃、7/70℃,and the highest strength was 0.72 MPa.Taking volume fraction 1.8% for example,the effects of pH on acylation degree under different temperatures were investigated by adopting ninhydrin-standard,and the results showed acylation degree and hydrophobic strength were not positive correlation.The infrared spectrum showed that acetic anhydride had cross linking reaction with the free amino of protein so that hydrophobic adhesion strength of soy-based wood adhesives were advanced.