A coupling agent is a chemical additive used to improve the strength of adhesion between two surfaces. Coupling agents are used to modify the surface of a material or interface, which helps to enhance the interfacial properties of the two materials being bonded. The most common types of coupling agent is a silane, which works by forming a covalent bond between the surface of a material and a substrate, such as an adhesive. Silicone coupling agent are used in a variety of industries including automotive, aerospace, biomedical, and industrial. They are also used in the production of composites, coatings, and adhesives.