It a series of copolymers of dimethylamine and epichlorohydrin. The repeating unit of the linear form of the copolymer is –CH2-CHOH-CH2-N+(CH3)2-. The presence of a quaternary ammonium group within the backbone of this molecule ensures that it papermaking operations. Molecular masses are typically between tens of thousands and hundreds of thousands of grams per mole. The product is usually delivered in solution form, with a solids level between about 10% and 50%, depending on the molecular mass.
The use and optimization of highly charged additives to a paper machine is never simple. Bu there is one sense in which the behavior of polyamines is simpler than some other highly charged cationic additives such as alum or PEI. The simplifying attribute of the most commonly used polyamines is that their charge doesn’t depend on pH. The quaternary ammonium groups remain cationic throughout the pH values of acidic and alkaline papermaking.