Abstract

The interests in biobased wood adhesives have been steadily increasing in recent years. Cottonseed protein isolate has shown potential as a renewable biobased adhesives. For a better understanding of the adhesive performance and mechanisms of cottonseed protein, we sequentially separated the isolated material into water-soluble (CSPw) and alkali-soluble (CSPa) fractions. The adhesive properties of both fractions on bonding maple wood veneers were tested at their natural pH (4.0 for CSPw and 7.0 for CSPa) and a common pH 11.0. The dry, wet, and soaked (i.e. wet and then re-dried) strength at break of the wood pairs bonded by CSPa were always higher than the values found for CSPw under the same conditions. Per the solubility and rheological analysis, the observed differences in bonding performance could be attributed to the fact that CSPw is more hydrophilic and lower in pI. ATR FTIR analysis was directly applied to the adhesive-coated surface area of maple strips cohesively broken by shear tests. Qualitative FTIR spectral features and quantitative contact angle measurement of the adhesive-coated maple surface evidenced the better wettability of cured CSPa than CSPw adhesives. Lesscarbohydrates leached out of CSPa during water soaking relative to CSPw. These observations increased the mechanistic knowledge of seed protein products functioning as wood adhesives, and would be helpful for the design and tuning of their future functional performance in green applications.

摘要

近年来，人们对生物基木材粘合剂的兴趣一直在稳步增长。棉籽分离蛋白已显示出作为可再生生物基粘合剂的潜力。为了更好地了解棉籽蛋白的粘附性能和机制，我们将分离的材料按顺序分为水溶性 (CSPw) 和碱溶性 (CSPa) 部分。在天然 pH 值（CSPw 为 4.0，CSPa 为 7.0）和常见 pH 值 11.0 下，测试了这两种组分在粘合枫木单板上的粘合性能。在相同条件下，由 CSPa 粘合的木材对的干、湿和浸泡（即湿后重新干燥）的断裂强度总是高于 CSPw 的值。根据溶解度和流变学分析，观察到的粘合性能差异可归因于 CSPw 更亲水且 pI 更低的事实。ATR FTIR 分析直接应用于通过剪切试验粘合断裂的枫木条的粘合剂涂层表面积。涂有粘合剂的枫木表面的定性 FTIR 光谱特征和定量接触角测量证明固化的 CSPa 比 CSPw 粘合剂具有更好的润湿性。相对于CSPw，在水浸泡过程中从CSPa 中浸出的碳水化合物较少。这些观察结果增加了对用作木材粘合剂的种子蛋白产品的机械知识，并将有助于设计和调整其未来在绿色应用中的功能性能。ATR FTIR 分析直接应用于通过剪切测试粘合断裂的枫木条的粘合剂涂层表面积。涂有粘合剂的枫木表面的定性 FTIR 光谱特征和定量接触角测量证明固化的 CSPa 比 CSPw 粘合剂具有更好的润湿性。相对于CSPw，在水浸泡过程中从CSPa 中浸出的碳水化合物较少。这些观察结果增加了对用作木材粘合剂的种子蛋白产品的机械知识，并将有助于设计和调整其未来在绿色应用中的功能性能。ATR FTIR 分析直接应用于通过剪切测试粘合断裂的枫木条的粘合剂涂层表面积。涂有粘合剂的枫木表面的定性 FTIR 光谱特征和定量接触角测量证明固化的 CSPa 比 CSPw 粘合剂具有更好的润湿性。相对于CSPw，在水浸泡过程中从CSPa 中浸出的碳水化合物较少。这些观察结果增加了对用作木材粘合剂的种子蛋白产品的机械知识，并将有助于设计和调整其未来在绿色应用中的功能性能。相对于CSPw，在水浸泡过程中从CSPa 中浸出的碳水化合物较少。这些观察结果增加了对用作木材粘合剂的种子蛋白产品的机械知识，并将有助于设计和调整其未来在绿色应用中的功能性能。相对于CSPw，在水浸泡过程中从CSPa 中浸出的碳水化合物较少。这些观察结果增加了对用作木材粘合剂的种子蛋白产品的机械知识，并将有助于设计和调整其未来在绿色应用中的功能性能。