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| Synonyms:Poly(ethyleneimine) Poly(aziridine) Aziridine polymer Poly(iminoethylene) Molecular Formula:C2H5N Molecular Weight: 43.07 HS Code: 3911900090 Grade:50% 98% Hazard Class:General Cargo | |||||||||
9002-98-6
bosschemical
9002-98-6
Polyethyleneimine (PEI; synonyms: polyaziridine, aziridine homopolymer, ethylenimine polymer) is a water-soluble cationic polymer built from repeating ethylenimine units (−CH₂CH₂NH−). It is supplied commercially as a light-yellow to colorless viscous aqueous solution (branched grades) or as a white solid (linear grades), and it carries one of the highest cationic charge densities of any commercial polymer: on average, every third atom along the backbone is a nitrogen atom that can be protonated.
Because the molecule is packed with primary, secondary and tertiary amine groups, PEI behaves simultaneously as a polycation, a chelating agent and an organic base. It binds electrostatically to negatively charged surfaces (cellulose fibers, clays, metal oxides, anionic dyes and pigments), chelates heavy-metal ions, and buffers across a high-pH window. That single-molecule versatility is the basis of nearly every industrial application, from papermaking and water treatment to electroplating and biotechnology.
A single polymer, four core value propositions:
Papermaking:a wet-strength agent, retention and drainage aid for tissue, filter and specialty paper grades;
Water Treatment:a high-cationic flocculant, sludge dewatering aid and heavy-metal chelant for industrial effluent;
Electroplating:a non-cyanide additive for metal finishing and an adhesion-promoting surface conditioner;
Item | Specification |
Chemical Name | Polyethyleneimine (Polyethylenimine, PEI) |
Synonyms | PEI; Polyaziridine; Aziridine homopolymer; Ethylenimine polymer; 2-Aziridine homopolymer |
CAS No. | 9002-98-6 (branched grades); 29320-38-5 (linear grades) |
EC No. (EINECS) | 618-480-9 (branched) |
Molecular Formula | (C₂H₅N)ₙ — repeating unit −CH₂CH₂NH− |
HS Code | 3911.90 (nitrogen-function polymers; 8-digit code may vary by destination) |
Appearance | Light-yellow to colorless viscous aqueous solution (branched); white solid (linear) |
Solubility | Freely soluble in water, methanol and ethanol; insoluble in benzene, diethyl ether and acetone |
Two structural forms dominate the market. Branched PEI (CAS 9002-98-6) is produced by acid- or base-catalyzed polymerization of aziridine and contains a random mix of primary (25%), secondary (50%) and tertiary (25%) amines; it is a liquid in its free-base form. Linear PEI (CAS 29320-38-5) is synthesized by ring-opening polymerization of 2-oxazoline followed by hydrolysis; it contains only secondary amines, is a crystalline solid at room temperature, and dissolves in hot water or low-pH aqueous media.
● Extremely high cationic charge density: one of the highest of any commercial polymer, giving strong electrostatic adsorption onto negatively charged fibers, particles, dyes and biological surfaces.
● Triple functionality in one molecule: acts as polycation, heavy-metal chelant and alkaline buffer, simplifying formulation and reducing the number of additives needed.
● Effective heavy-metal removal: amine groups chelate Cu²⁺, Ni²⁺, Zn²⁺, Pb²⁺ and other metal ions, enabling metal recovery or safe precipitation from wastewater.
● Proven wet-strength performance: improves wet tensile strength and retention of fillers/fines in papermaking, with fast curing without heat or cross-linkers.
● Non-cyanide and environmentally friendlier: replaces cyanide-based systems in electroplating and metal finishing, reducing toxicity and compliance burden.
● Broad pH and temperature tolerance: stable and effective across a wide working window, from acidic rinse baths to alkaline paper furnish.
1 Papermaking (Core Application)
PEI is a classic wet-end additive for paper grades that must keep their strength when wet:
● Wet-strength agent: binds electrostatically and covalently to cellulose fibers, raising wet tensile strength in un-sized absorbent papers such as filter paper, tissue, blotting paper and specialty wipes;
● Retention and drainage aid: flocculates fillers, fines and pigments, speeding up water drainage on the wire and improving first-pass retention;
● Dye and pigment fixative: fixes anionic direct and acid dyes onto fiber, reducing dye bleeding in colored tissue and décor papers;
● Binder activator: enhances adhesion of coating binders and improves surface strength of coated grades.
2 Water Treatment
PEI's dense positive charge and chelating amine groups make it a versatile treatment chemical for industrial water:
● Flocculant and coagulant aid: neutralizes anionic colloids and suspended solids in municipal and industrial effluent;
● Sludge dewatering: improves dewatering rate and reduces sludge volume in wastewater treatment plants;
● Heavy-metal scavenger: chelates and precipitates Cu, Ni, Zn, Pb, Cd ions from electroplating rinses and mining wastewater;
● Pretreatment and polishing: conditions feed water for RO/UF membranes and clarifies process water in textile, paper and metalworking plants.
3 Electroplating & Metal Finishing
● Non-cyanide plating additive: complexes metal ions in alkaline zinc, copper and alloy baths, giving bright, uniform deposits without cyanide;
● Adhesion promoter and surface conditioner: primes metal and plastic substrates for subsequent coating or plating layers;
● Leveling and brightening agent: improves deposit leveling and grain refinement in acid copper and nickel systems.
4 Coatings, Adhesives, Gas Treatment & Biotechnology
● Coatings and inks: pigment dispersant, adhesion promoter and cross-linking component in waterborne and epoxy systems;
● Adhesives and composites: coupling agent for fiber–matrix bonding and a curing agent for epoxy resins;
● Gas separation and CO₂ capture: amine-rich structure is widely studied as a solid adsorbent or membrane component for CO₂ capture;
Packaging (customizable):
● Solution grades: 25 kg HDPE jerry can, 200 kg HDPE drum, 1,000 L IBC, or ISO tank for large orders;
● Anhydrous/solid grades: 25 kg fiber drum with PE liner, or 500 – 1,000 kg FIBC;
● Containers are nitrogen-blanketed and tightly sealed to prevent moisture pick-up and carbonation.
Storage:
● Keep in a cool, dry, well-ventilated area away from direct sunlight and heat;
● Keep containers tightly closed (hygroscopic; absorbs CO₂ from air);
● Avoid contact with strong acids and oxidizing agents;
● Protect aqueous solutions from freezing; recommended storage 5 °C – 35 °C.
● Factory-direct supply: own production capacity, transparent pricing, no middleman markup;
● Stable quality: strict internal control, every batch tested, COA with every shipment;
● Export experience: familiar with sea/air shipping documentation for chemical commodities, complete paperwork support;
● Fast response: quotations and technical support (COA, application advice) within 24 hours; small trial orders accepted.
PEI is a multi-purpose cationic polymer. Its main industrial uses are as a wet-strength/retention agent in papermaking, a flocculant and heavy-metal chelant in water treatment, a non-cyanide additive in electroplating, and a pigment dispersant/adhesion promoter in coatings. In biotechnology it is the standard non-viral carrier for gene transfection.
Yes — “polyethyleneimine” and “polyethylenimine” (PEI) are two accepted spellings of the same polymer. “Polyaziridine” is the older synonym. All refer to the ethylenimine polymer family (CAS 9002-98-6 branched / 29320-38-5 linear).
As a raw material, PEI is an alkaline, skin- and eye-irritating substance — handle with gloves, goggles and adequate ventilation, and avoid inhalation of mists or dust. It is an industrial/technical chemical, not a food ingredient. Purified grades intended for biotech use meet stricter quality limits and should be handled under the user's own validated protocols.
