In order to improve the bonding strength of structures and avoid interface damage, extensive research has been conducted on bonding processes (joint design, surface pretreatment, curing process, etc.) and adhesive properties, and many solutions have been proposed. The low-temperature plasma modification method can improve surface wettability and reduce interface defects in bonding; Clean the surface of contaminated impurities to avoid the formation of weak interface layers at the bonding interface; It can activate the surface and enhance the interfacial bonding effect; It does not cause secondary pollution to the surface and has attracted widespread attention.

Introduction to Bonding Technology

Bonding technology refers to a method of connecting an adhesive to the adherend using chemical reactions or physical interactions. It belongs to one of the three major bonding technologies (welding, mechanical connection, and bonding) and has a long history of use. In recent years, with the rapid development of the adhesive industry, adhesive technology has also developed rapidly, and its practical production applications have become increasingly widespread. Currently, it has involved various industries and plays an increasingly important role in the national economy.

Bonding technology has a wide range of applications in actual production. It can not only be used in structural join, but also in the sealing of mechanical equipment parts, repair of old parts and other fields, and even can be used to make up for some defects in processing technology. In addition, bonding technology has a wide range of applicable materials, which can connect metal materials, as well as non-metallic materials such as glass, ceramics, plastics, and even be used for the connection between metal and non-metallic materials.

In the bonding structure, due to the differences between the two surfaces of the bonding material, and the fact that the surface of the bonded material is easily contaminated during exposure to the atmospheric environment, it can lead to the inability to achieve a good connection between the two at the bonding interface, making the bonding interface a weak point in the connecting structure and affecting the bonding quality. However, due to the advantages of low-temperature plasma modification methods in cleaning material surfaces, improving surface wettability, and increasing surface free energy, low-temperature plasma modification pre-treatment has been applied in the bonding process, especially in bonding, and has received widespread attention.

Plasma treatment

(1) After low-temperature plasma surface treatment, polar groups of - OH and - COOH were introduced on the material surface, increasing the surface free energy and allowing the adhesive to fully wet the surface of high-density polyethylene film; (2) Plasma has an etching effect on the surface of high-density polyethylene film, increasing the roughness of the surface, enhancing the mechanical bonding between the adhesive and the substrate, and increasing the bonding area; (3) The COOH functional group introduced by plasma modification on the surface of HDPE film reacts with - OH on the surface of silane glass to form hydrogen bond, and further dehydrates to form covalent bond, thus realizing chemical bonding.