Chemical combination theory
The theory is that the coupling agent contains a chemical functional group that can form covalent bonds with the silanol groups on the surface of the glass fiber or molecules on the surface of other inorganic fillers. In addition, the coupling agent also contains a different functional group and Polymeric molecules are bonded to obtain a good interfacial bond, and the coupling agent acts like a bridge that interconnects the inorganic and organic phases.
The silane coupling agent is taken as an example to explain the chemical bond theory. For example, aminopropyltriethoxysilane, when it is first treated with inorganic fillers (such as glass fiber, etc.), the silane is first hydrolyzed into silanol, and then the silanol group undergoes a dehydration reaction with the surface of the inorganic filler to perform chemical bonding and reaction. The formula is as follows:
The groups in silane are hydrolyzed—the hydroxyl group reacts with the inorganic filler after hydrolysis—the Y group in the coupling agent will interact with the organic polymer when the inorganic material filled with the coupling agent is filled to prepare the composite material. In the end, the bridge between the inorganic filler and the organic matter is set up.