Definition of Adhesive
A class of substances, whether natural or synthetic, organic or inorganic, that can connect two or more components or materials together through interfacial adhesion and material cohesion are collectively referred to as adhesives, also known as binders, and commonly called glue in daily usage.
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Bonding (Adhering): It refers to the state in which two surfaces are joined together by chemical forces, physical forces, or a combination of both.
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An adhesive must first adhere to the surface of the adherend. This is because an adhesive force is generated between the two phases, and this force is derived from secondary valence forces or primary valence forces.
Cohesion: It is the state in which the particles within a single substance are held together by primary valence forces (including ionic bonds, covalent bonds, coordination bonds, metallic bonds, etc.) and secondary valence forces (including van der Waals forces, hydrogen bonds). The cohesive force of an adhesive is related to factors such as intermolecular forces, relative molecular mass, degree of cross - linking, crystallization, and molecular entanglement.
