cohesion

Cohesion is a physical phenomenon that describes the ability of molecules of a substance to stick and stay together. This phenomenon plays an important role in chemistry and physics.

In liquids, cohesion is the force that causes the molecules to stick together and form a cohesive mass. These forces can vary in strength and depend on the type of liquid and molecules. For example, water has high cohesion, which means it is able to create surface tension and form droplets.

In solids, cohesion is the force that causes the atoms or molecules of the material inside to bind together and stabilize the material. These forces are also dependent on the type of material and can vary from molecule to molecule.

In the case of adhesives, cohesion refers to the forces that cause the adhesive to hold itself together. On the one hand, these cohesive forces determine the toughness (viscosity) and the dripping behavior (rheology) of the adhesive that has not yet solidified. its processing properties. On the other hand, together with the adhesive forces, they determine the strength of the bond against mechanical stress.

The cohesive forces in an adhesive are described by parameters such as tensile strength, E-modulus, elongation at break or Shore hardness and should not be confused with the strength properties of a bond such as tensile shear strength and shear modulus.

Overall, cohesion is an important concept in physics and chemistry, helping to understand the properties of liquids and solids and explaining the role of interactions between molecules in materials and systems.