What does the degree of crosslinking of ion exchange resins refer to?

It refers to the network structure formed by the polymerization of various organic materials, which constitutes the skeleton of the ion exchange resin. This is expressed as a percentage; the higher the degree of cross-linking, the smaller the mesh size. As a result, large ions have difficulty entering the resin during exchange, but this improves the selectivity of the exchange process.

Crosslinking degree is one of the important properties of styrene-based resins. The crosslinking degree refers to the mass percentage of divinylbenzene (commonly known as a “crosslinking agent”) contained in the styrene resin. That is: Crosslinking degree = mass of divinylbenzene / (mass of styrene + mass of divinylbenzene) * 100%. When the crosslinking degree of the resin is low, its swelling capacity in water is high; this results in larger crosslinking pores in the resin and a faster exchange rate, but the strength of the resin is low. Conversely, when the crosslinking degree of the resin is high, its crosslinked pores are small, the resin has high strength, but it has poor swelling behavior in water and a slow reaction rate. The styrene-based resins used in chemical water treatment generally have a crosslinking degree ranging from 4% to 14%, with a crosslinking degree of around 7% yielding the most optimal performance.