Principles of Adhesive Gluing

The use of adhesives has a long history, but the development of theories and the principles of adhesion is relatively late. There are several theories to explain the role of adhesives:

(1) Mechanical theory: From a microscopic point of view, any smooth solid surface is rough, uneven, full of pores, and the adhesive penetrates into the depressions and pores of the surface, solidifies and anchors it, resulting in a firm bond;

(2) Electrostatic theory: The electrostatic theory believes that an electric double layer is generated at the interface between the adhesive and the solid to be bonded, so that the electrostatic force is generated and the two are glued together;

(3) Adsorption theory: Adsorption theory believes that the adhesive and the material to be bonded are in close contact through the wetting of the interface, resulting in intermolecular attractive force, thereby generating the bonding strength;

(4) Diffusion theory: Explain the bonding of polymer materials. It is believed that the bonding between high polymer and high polymer is the mutual diffusion and bonding of molecular segments on the two surfaces;

(5) Other explanations include the chemical bond theory, which believes that bonding is the result of the formation of chemical bonds between the adhesive and the surface molecules of the bonded object.