Broussonetiapapyrifera leaf protein was used as a biomass feedstock to prepare wood adhesives, and the influence of cutting modes (cutting frequencies and cutting heights) on leaf protein content and reactivity was studied in this paper. Bonding performance of Broussonetiapapyrifera leaf protein-based adhesives were evaluated by shear strength of plywood. Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetry (TG), and scanning electron microscope (SEM) were used to analyze them. The results indicated that: (1) the leaf protein content gradually increased as the cutting height increased, but it presented a decreasing trend as the cutting frequency increased. When the cutting frequency is two times per year and the cutting height is 30 cm, this leaf protein-based adhesive exhibited the best bonding strength with 0.75 MPa. (2) Cutting frequency and cutting height have no significant correlations to the reactivity of leaf protein with the crosslinker. (3) DSC and FTIR indicated that both leaf protein content and reactivity appeared to exert an influence on the bonding properties of the protein adhesives, and the latter is more pronounced. (4) TG and SEM analyses indicated that under different cutting modes, leaf protein content, especially protein reactivity, had a great effect on the thermal properties of the adhesives. (5) Contact angle analysis showed that Broussonetiapapyrifera leaf protein-based adhesives had good wettability on wood surfaces. Under different cutting modes with the difference of leaf protein content and reactivity, the crosslinking degree of the adhesives with crosslinker and compactness of the cured adhesives were different and thus affect their bonding strength and water resistance.

中文翻译：

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纸莎草切叶方式对其蛋白质基胶粘剂粘合性能的影响

以布鲁氏假单胞菌叶片蛋白为生物质原料制备木材胶粘剂，研究了切削方式（切削频率和切削高度）对叶片蛋白质含量和反应性的影响。纸状布鲁氏菌的结合性能通过胶合板的剪切强度评估基于叶蛋白的胶粘剂。使用傅里叶变换红外光谱（FTIR），差示扫描量热法（DSC），热重法（TG）和扫描电子显微镜（SEM）进行分析。结果表明：（1）叶片蛋白质含量随着cutting插高度的增加而逐渐增加，但随着cutting插频率的增加而呈现下降趋势。当每年的切割次数为两次且切割高度为30 cm时，这种基于叶蛋白的粘合剂在0.75 MPa时表现出最佳的粘合强度。（2）切割频率和切割高度与叶蛋白与交联剂的反应性无显着相关性。（3）DSC和FTIR表明，叶片蛋白质含量和反应性似乎都对蛋白质胶粘剂的粘合性能产生影响，而后者更为明显。（4）TG和SEM分析表明，在不同的切割方式下，叶片蛋白质含量，特别是蛋白质反应性，对胶粘剂的热性能影响很大。（5）接触角分析表明布鲁氏纸莎草叶蛋白基胶粘剂在木材表面具有良好的润湿性。在不同的切割方式下，叶蛋白含量和反应性不同，粘合剂与交联剂的交联度和固化后的粘合剂的致密性也不同，从而影响其粘合强度和耐水性。