ABSTRACT

Polymer chain-extenders with one (AE, i.e., aminoethanol), two (APD, i.e., 2-amino-1,3-propanediol), and three (tris, i.e., 2-amino-2-(hydroxymethyl)-1,3-propanediol) pendant ethanol groups were used in a model epoxy structural adhesive to investigate their influence on joint strength and durability. While AE and APD showed modest improvements in lap shear strength, the bond durability of adhesive joints was improved dramatically using tris without the need for a chemical surface treatment. Specifically, single lap shear measurements (ASTM D1002 10) using 2024-T3 adherends demonstrated that tris (0.28 − 1.4 wt%) incorporated into a model structural adhesive can improve the lap shear strengths by 50% under dry conditions and by 64% under hot/wet conditions (immersion in water at 63°C for 14 days). The performance under hot/wet conditions is similar to that observed for adherends chemically surface treated with a commonly used silane coupling agent (i.e., 3-aminopropyltriethoxysilane). This enhanced performance of tris is likely a result of improved interfacial interactions because the small amounts of tris additive had an insignificant effect on the mechanical properties of the adhesive formulations themselves based on dynamic mechanical analysis. In addition, X-ray photoelectron spectroscopy measurements on fractured specimens showed that the adhesive remained on the substrate, implying largely cohesive failure in the specimens.

摘要

具有一种（AE，即氨基乙醇）、两种（APD，即 2-氨基-1,3-丙二醇）和三种（三，即 2-氨基-2-（羟甲基）-1）的聚合物扩链剂， 3-丙二醇）乙醇侧基被用于模型环氧结构粘合剂中，以研究它们对接头强度和耐久性的影响。虽然 AE 和 APD 在搭接剪切强度方面表现出适度的改进，但使用 tris 无需化学表面处理，粘合剂接头的粘合耐久性显着提高。具体而言，使用 2024-T3 被粘物的单搭接剪切测量 (ASTM D1002 10) 表明，加入模型结构粘合剂中的 tris (0.28 - 1.4 wt%) 可以在干燥条件下将搭接剪切强度提高 50%，在热条件下提高 64% /潮湿条件（在 63°C 的水中浸泡 14 天）。在热/湿条件下的性能类似于用常用的硅烷偶联剂（即3-氨基丙基三乙氧基硅烷）进行化学表面处理的被粘物所观察到的性能。tris 的这种增强性能可能是界面相互作用改善的结果，因为根据动态力学分析，少量的 tris 添加剂对粘合剂配方本身的机械性能影响不大。此外，对断裂试样的 X 射线光电子能谱测量表明粘合剂保留在基材上，这意味着试样中的内聚破坏很大。tris 的这种增强性能可能是界面相互作用改善的结果，因为根据动态力学分析，少量的 tris 添加剂对粘合剂配方本身的机械性能影响不大。此外，对断裂试样的 X 射线光电子能谱测量表明粘合剂保留在基材上，这意味着试样中的内聚破坏很大。tris 的这种增强性能可能是界面相互作用改善的结果，因为根据动态力学分析，少量的 tris 添加剂对粘合剂配方本身的机械性能影响不大。此外，对断裂试样的 X 射线光电子能谱测量表明粘合剂保留在基材上，这意味着试样中的内聚破坏很大。