50%，60% Poly(dimethylamine-co-epichlorohydrin) CAS 25988-97-0

What is dimethylamine-co-epichlorohydrin copolymer (Poly(dimethylamine-co-epichlorohydrin))? What are its industrial applications?

1. What is Poly(dimethylamine-co-epichlorohydrin)?

Poly(dimethylamine-co-epichlorohydrin), also known as dimethylamine-epiochloropropane copolymer (also called epichlorohydrin-dimethylamine copolymer, poly(dimethylamine-co-epiochloropropane), or polyamine, polyquaternium-2 (CAS No. 25988-97-0), is a cationic linear polyquaternium salt produced by the polycondensation reaction of dimethylamine and epichlorohydrin. It is one of the most important cationic polymeric flocculants in industry, and its structure can be simplified as follows:

[-(CH2CH(OH)CH2-N(CH3)2-)-]n (Polyquaternium-2, CAS No.: 25988-97-0, cationic linear polyelectrolyte)

It is typically a colorless to pale yellow, transparent, viscous liquid (aqueous solution), readily soluble in water, and possesses a high positive charge density. It maintains good performance in acidic, alkaline, and hard water environments. During use, it produces no foam, has no irritating odor, and is non-toxic. It exhibits extremely strong adsorption and bridging capabilities for colloidal substances. In industrial production, its flocculation performance is often enhanced by introducing a small amount of cross-linking agent (such as 1,6-hexanediamine) to increase its molecular weight.

From a molecular structure perspective, the copolymer backbone is densely distributed with quaternary ammonium cationic groups (-N+(CH3)2-). This "high charge density + linear long chain" structure enables it to neutralize negatively charged colloidal particles in water and aggregate tiny particles into large flocs for sedimentation through adsorption bridging. It can also neutralize dye molecules and anionic substances, thus becoming a "multi-talented" agent for flocculation, decolorization, sterilization and algae removal.

Chemically, this copolymer is a cationic polyelectrolyte with stable properties. It is compatible with inorganic flocculants such as polyaluminum chloride and has low toxicity. However, concentrated solutions can irritate the eyes and skin. It should be stored in a sealed, moisture-proof container and away from high temperatures.

Industrial-grade products refer to aqueous solutions intended for industrial applications such as water treatment, papermaking, oil fields, and textiles. Common specifications include a solid content of around 50% (e.g., a 50% aqueous solution). Compared to daily chemical-grade products, industrial-grade products place greater emphasis on the following indicators:

1. Solid content

Solid content determines the dosage of active ingredients and the flocculation effect. The common specification is an aqueous solution of about 50%, which is the core indicator of product specifications.

2. Viscosity (molecular weight)

Viscosity reflects the molecular weight of the polymer. The higher the molecular weight, the stronger the adsorption and bridging ability and the better the flocculation effect. It is a key indicator for measuring the quality of a product.

3. cationicity

Cationicity reflects the positive charge density, determines the charge neutralization capacity, and directly affects the removal efficiency of negatively charged colloids and dyes.

4. pH value

pH value affects product stability and formulation compatibility, and must be controlled within the indicated range to ensure normal use in acidic, alkaline, and high-hardness water environments.

5. Free epichlorohydrin monomer content

Epichlorohydrin is a carcinogenic monomer, and the residual monomer content in polymers is a key safety indicator that must be strictly controlled and tested regularly.

6. Appearance and color

Appearance and color (APHA) reflect product quality and batch stability; the liquid must be colorless to pale yellow and transparent.

7. Solubility

The product must dissolve quickly and completely in water, leaving no gel or flocculent residue, to ensure its effectiveness.

II. What are the uses of industrial-grade Poly (dimethylamine-co-epichlorohydrin)?

This industrial-grade copolymer, with its unique structure of "high charge density + linear long chain", is widely used in flocculation, decolorization, sterilization and separation.

1. Water treatment flocculants (core application)

This copolymer is a cationic polymeric flocculant that helps neutralize colloidal charges , adsorb, bridge, coagulate, and settle, and remove suspended solids, turbidity, and COD. It is also commonly used as a coagulant aid for inorganic flocculants such as polyaluminum chloride.

（1）This copolymer is used as a polymeric flocculant and coagulant aid in drinking water treatment. It is often used in combination with polyaluminum chloride to help remove suspended solids and impurities from turbid river water. The tap water we drink every day may be indirectly involved in the purification process (the residue after treatment is extremely low and meets drinking water hygiene standards).

( 2 ) This copolymer is the main flocculant for municipal sewage and industrial wastewater treatment, which helps to remove suspended solids, reduce COD and color. It may be indirectly involved in the chain of our domestic sewage being discharged into rivers and lakes after treatment.

2. Dye wastewater decolorizing agent

This copolymer exhibits excellent charge neutralization and decolorization capabilities for anionic dyes such as reactive and disperse dyes, and is effective within a pH range of 2-10. It is a highly efficient flocculant for decolorizing dyeing and printing wastewater.

3. bactericide and algaecide

This copolymer is a non-foaming bactericide and algaecide used for algae control in swimming pools, whirlpools, landscape water features, and industrial circulating cooling water systems. It helps maintain water clarity and prevents scale buildup and clogging in pipes and heat exchangers.

4. Paper retention and filtration aids

This copolymer is used as a retention and filtration aid in the wet end chemistry of papermaking, helping to retain fibers, fillers and fine particles, improving paper strength, enhancing filtration performance and reducing white water load.

5. Oilfield chemicals

This copolymer is used as a demulsifier and oil-water separator for oilfield produced fluids, helping to break up and separate oil-water emulsions. It is also used as a treatment aid in drilling and oil production processes, serving the petroleum extraction and refining industry.

6. Rubber latex coagulant

This copolymer is used as a coagulant for synthetic rubber latexes such as styrene-butadiene rubber, helping latex particles to aggregate into rubber blocks. It is an important auxiliary agent in the post-processing of synthetic rubber.

7. Food processing aids (for permitted uses)

Within the limits permitted by U.S. FDA regulations, this copolymer is classified as a food processing aid for use as a clarification and filtration aid in specific food processing techniques.

8. Other applications

Including mining wastewater treatment, sludge dewatering and conditioning, and the extension of daily chemical conditioning agents (polyquaternium salt-2), the application scope of industrial-grade products continues to expand as environmental regulations become stricter.

It should be noted that industrial-grade specifications do not equate to "risk-free": although the copolymer is low in toxicity, concentrated solutions can irritate the eyes and skin, and protective equipment should be worn during handling; epichlorohydrin is a carcinogenic monomer, and it is essential to control the residual free monomer in the product and to treat waste liquid in compliance with regulations; its biodegradability and environmental behavior are key areas of environmental concern.

Summarize

Poly(dimethylamine-co-epichlorohydrin), or dimethylamine-epimylochloropropane copolymer (polyamine, polyquaternary ammonium salt-2, CAS No. 25988-97-0), is a cationic linear polyquaternary ammonium salt obtained by the condensation polymerization of dimethylamine and epichlorohydrin. It is typically a colorless to pale yellow viscous aqueous solution and, due to its "high charge density + linear long chain" structure, has become an important cationic polymeric flocculant in the industrial field. In daily life, we encounter it through tap water purification, swimming pool algae removal, sewage treatment, paper, printing and dyeing, and petroleum products. In industry, this copolymer is widely used as a water treatment flocculant, a decolorizing agent for dye wastewater, a bactericide and algaecide, a paper retention and filtration aid, an oilfield demulsifier, a rubber latex coagulant, and a food processing aid. It serves as a bridge between "cationic polyelectrolyte chemistry" and "water treatment, papermaking, oilfields, and textiles" as a polymeric flocculant.