Sodium polystyrene sulfonate (INN

International Nonproprietary Name

An International Nonproprietary Name is the official nonproprietary or generic name given to a pharmaceutical substance, as designated by the World Health Organization...

, trade names Kayexalate, Kionex, Resonium A) is a type of polymer

Polymer

A polymer is a large molecule composed of repeating structural units. These subunits are typically connected by covalent chemical bonds...

 and ionomer

Ionomer

An ionomer is a polymer that comprises repeat units of both electrically neutral repeating units and a fraction of ionized units...

 based on polystyrene

Polystyrene

Polystyrene ) also known as Thermocole, abbreviated following ISO Standard PS, is an aromatic polymer made from the monomer styrene, a liquid hydrocarbon that is manufactured from petroleum by the chemical industry...

. It is the sodium salt of polystyrene sulfonic acid.
The polyanion is readily soluble in water, and insoluble in lower alcohols. The solid appears as white or off-white powder.

It may be prepared by polymerization

Polymerization

In polymer chemistry, polymerization is a process of reacting monomer molecules together in a chemical reaction to form three-dimensional networks or polymer chains...

 or copolymerization of sodium styrene sulfonate or by sulfonation

Aromatic sulfonation

Aromatic sulfonation is an organic reaction in which a hydrogen atom on an arene is replaced by a sulfonic acid functional group in an electrophilic aromatic substitution.-Mechanism:...

 of polystyrene

Polystyrene

Polystyrene ) also known as Thermocole, abbreviated following ISO Standard PS, is an aromatic polymer made from the monomer styrene, a liquid hydrocarbon that is manufactured from petroleum by the chemical industry...

.