keresztkötéses

Keresztkötéses is a Hungarian term that translates to "cross-linked" in English. It describes a material or structure where individual polymer chains are chemically bonded to each other at various points, forming a three-dimensional network. This cross-linking process significantly alters the material's properties compared to its un-cross-linked counterpart, which consists of linear or branched chains that can slide past each other.

The degree of cross-linking, which refers to the number of cross-links per unit volume or per chain, is a crucial factor determining the final characteristics of the material. Higher cross-linking generally leads to increased rigidity, strength, and thermal stability. It also reduces solubility, making the material more resistant to solvents and swelling. Conversely, lower cross-linking results in more flexible and elastomeric materials.

Common examples of cross-linked polymers include vulcanized rubber, where sulfur bridges are formed between polymer chains, giving it its characteristic elasticity and durability. Many thermosetting plastics, such as epoxy resins and phenolic resins, are also cross-linked during their curing process, resulting in rigid and heat-resistant materials. The process of cross-linking is essential in the production of a wide range of products, from tires and hoses to coatings and adhesives.