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Description
Cationic Polyelectrolyte, commonly known as PolyDADMAC (Polydiallyldimethylammonium Chloride), is a high-molecular-weight water-soluble cationic polymer extensively used as a coagulant, flocculant, charge neutralizer, retention aid, and conditioning polymer in water treatment, paper manufacturing, mining, textiles, cosmetics, and various industrial processes. It is synthesized through the polymerization of the quaternary ammonium monomer diallyldimethylammonium chloride (DADMAC), resulting in a permanently positively charged polymer chain.
Unlike many cationic polymers whose charge depends on pH, PolyDADMAC contains quaternary ammonium groups that remain positively charged over a wide pH range. This permanent cationic charge enables efficient neutralization of negatively charged particles, colloids, organic matter, microorganisms, dyes, and suspended solids. Consequently, PolyDADMAC has become one of the most widely used cationic polymers for clarification, sludge dewatering, papermaking, and wastewater treatment.
In addition to industrial applications, lower molecular weight grades are employed in cosmetic and personal care products as conditioning agents, antistatic additives, and film-forming polymers that improve hair manageability and skin feel.
CAS Number
CAS Number: 26062-79-3
Monomer (DADMAC):
CAS Number: 7398-69-8
Synonyms
Physical Properties
PolyDADMAC is typically supplied as a clear to pale yellow, viscous aqueous solution, although solid powder grades are also available. The product is odorless or possesses only a faint characteristic odor and exhibits excellent water solubility.
Typical characteristics include:
Its viscosity increases with molecular weight and polymer concentration.
Chemical Properties
PolyDADMAC consists of repeating quaternary ammonium units connected through carbon-carbon polymer backbones. Because the nitrogen atoms carry permanent positive charges, the polymer exhibits excellent electrostatic attraction toward negatively charged substances.
Important chemical characteristics include:
Unlike amine-based polymers, PolyDADMAC maintains its cationic character even under highly alkaline conditions.
Manufacturing Process
PolyDADMAC is manufactured through free-radical polymerization of diallyldimethylammonium chloride (DADMAC) in aqueous solution.
Typical production stages include:
Reaction conditions are carefully controlled to obtain the desired molecular weight, viscosity, and charge density for specific industrial applications.
Mechanism of Action
PolyDADMAC functions through electrostatic interactions.
The positively charged polymer chains rapidly adsorb onto negatively charged particles suspended in water. This neutralizes surface charges, reducing electrostatic repulsion between particles and promoting aggregation into larger flocs that settle more readily.
Its principal mechanisms include:
In papermaking, PolyDADMAC improves retention of fibers and fillers by binding negatively charged cellulose particles.
Applications
PolyDADMAC has extensive industrial applications.
Water Treatment
Paper Industry
Textile Industry
Mining Industry
Cosmetics
Oil and Gas Industry
Advantages
PolyDADMAC offers numerous industrial benefits.
