Ion exchange resin is a kind of macromolecular compound with a network structure and functional groups. It is mainly composed of the following three parts:
(1) Monomer. It is a low molecular organic matter that can be polymerized into a macromolecular compound. It is the main component of ion exchange resin, so it is also called the matrix. Such as styrene, acrylic acid, etc.
(2) Cross-linking agent. It is a substance that can play a bridging role when linear structure molecules are condensed, so that the groups in its molecules are bonded to each other to form an insoluble network. The commonly used cross-linking agent for ion exchange resin is divinylbenzene. The percentage of cross-linking agent in ion exchange resin is called cross-linking degree. The cross-linking degree of ion exchange resin used in chemical desalination water treatment is generally in the range of 7% to 12%.
(3) Exchange group. It is a group with active ions (exchangeable ions) connected to the monomer. It can be introduced into the resin by chemical reaction from low molecular weight molecules with dissociation ability [such as sulfuric acid H2SO4, organic amine N(CH)3, etc.]; it can also be directly polymerized by monomers with dissociation groups (such as methacrylic acid).