Crosslinkelés

Crosslinkelés refers to the process of creating covalent bonds between polymer chains. These bonds effectively tie the individual polymer molecules together, forming a three-dimensional network structure. This network significantly alters the physical and chemical properties of the polymer compared to its uncrosslinked, linear counterpart.

The crosslinking process typically involves exposing the polymer to a crosslinking agent or energy source, such as heat, radiation, or chemical compounds. The specific method depends on the type of polymer and the desired degree of crosslinking. For example, vulcanization of rubber is a well-known crosslinking process that uses sulfur to create sulfur bridges between polymer chains, enhancing elasticity and durability.

The presence of crosslinks restricts the movement of polymer chains relative to each other. This restriction leads to increased mechanical strength, higher tensile strength, improved solvent resistance, and reduced creep. However, excessive crosslinking can make the material brittle and reduce its flexibility. The density of crosslinks, known as the crosslink density, is a critical parameter that dictates the extent of these property modifications. Crosslinked polymers are often used in applications requiring high performance, such as in tires, adhesives, coatings, and thermosetting plastics.