胶粘剂/胶黏剂为什么能粘接的胶接理论之化学键理论

胶接理论之化学键理论

化学键理论认为胶接作用主要是化学键力作用的结果，这是一种由化学反应产生化学键观点来解释粘接现象的理论。该理论认为，胶接作用是由于胶黏剂与被粘物之间的化学结合力而产生的，有些胶黏剂能与被粘物表面的某些分子或基团形成化学键。化学键包括离子键、共价键和金属键，而化学键是分子中相邻两原子之间的强烈吸引力，一般化学键要比分子间的范德华力大一两个数量级，这种化学键的结合十分牢固。由于化学键对胶接强度有相当大的影响，所以早就被人们所重视。化学键理论被许多事实所证实，在相应的领域中是成功的。尤其重要的是，界面有了化学键的形成，对胶接接头的抗水和介质腐蚀的能力有显著提高，这是不可忽视的。当然，界面化学键的形成对抗应力破坏、防止裂缝扩展的能力也有积极作用。

但这仅限于某些特定的反应性的胶黏剂品种中。如果在粘接中或多或少是由化学键产生的粘接力，那么粘接强度就要高得多。遗憾的是，在现有的粘接中，由化学键力产生的粘接力很少，这也许就是到目前为止粘接强度还不是很高的原因之一。

According to the chemical bond theory, bonding is mainly the result of chemical bond force, which is a theory to explain the bonding phenomenon from the viewpoint that chemical reaction produces chemical bond. According to the theory, the bonding is due to the chemical bonding force between the adhesive and the adherent. Some adhesives can form chemical bonds with some molecules or groups on the surface of the adherent. Chemical bond includes ionic bond, covalent bond and metal bond. Chemical bond is a strong attraction between two adjacent atoms in a molecule. Generally, chemical bond is one or two orders of magnitude larger than van der Waals force between molecules. This kind of chemical bond is very strong. Because the chemical bond has a great influence on the bonding strength, it has been paid attention to for a long time. The theory of chemical bond has been proved by many facts and is successful in the corresponding fields. In particular, the formation of chemical bonds at the interface can significantly improve the water and medium corrosion resistance of the bonded joint, which can not be ignored. Of course, the formation of interfacial chemical bonds also has a positive effect on the ability to resist stress damage and prevent crack propagation.

But this is limited to certain reactive adhesives. If the adhesive force is more or less generated by chemical bond, the adhesive strength is much higher. Unfortunately, in the existing adhesive, the adhesive force produced by the chemical bond force is very small, which may be one of the reasons why the adhesive strength is not very high so far.