Polyethyleneimine PEI | CAS 9002-98-6 | China Manufacturer
Product Name: Polyethyleneimine (PEI)
Synonym: Polyaziridine; Ethyleneimine Polymer; PEI Resin
CAS Number: 9002-98-6
Molecular Formula: (C2H5N)n
Available MW Grades: 600 · 1,800 · 10,000 · 25,000 · 70,000
Appearance: Pale yellow, viscous liquid (or 50% aqueous solution)
Water Solubility: Fully soluble — all grades
Amine Value: High cationic density (primary, secondary, tertiary amines)
Packaging: 1 kg / 25 kg / 200 kg
Lead Time: 3–7 business days from stock
Certification: ISO 9001:2015 · COA & SDS with every batch
- Worldwide Delivery
- Quality Assurance
- 24/7 Customer Service
Product Introduction
Five MW Grades · Water Treatment · Adhesion Promotion · Wet Strength · Biomedical Research
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MW RANGE
600 – 70,000
Five grades, GPC verified
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AMINE VALUE
High
Titration measured
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APPEARANCE
Colorless to Pale Yellow Liquid
Visual check
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PACKAGING
1 kg – 200 kg
Custom options
Request COA / SDS | Technical Questions? Visit FAQ
✅ Response within 12 hours · 📄 COA & SDS with every shipment
Product Overview
Polyethyleneimine (PEI, CAS 9002-98-6) is a water-soluble cationic polymer with a high density of primary, secondary, and tertiary amine groups. These amines give PEI its defining property: a strong positive charge that binds to any negatively charged surface - cellulose fibers, pigments, metal ions, and biological membranes.
Alfa Chemical supplies PEI in five molecular weight grades - 600, 1,800, 10,000, 25,000 and 70,000 - each targeting different application needs. Low MW grades (600–1,800) are used for crosslinking and adhesion promotion; medium MW (10,000) for flocculation and wet strength; high MW (70,000) for demanding flocculation and biomedical transfection.
PEI is fully miscible with water at all concentrations and compatible with most polar solvents. It is supplied as a colorless to pale yellow viscous liquid or as a 50% aqueous solution, depending on grade. The product does not contain formaldehyde or chlorine - a key differentiator in paper and water treatment applications where residual chemicals are restricted.
Alfa Chemical produces PEI at our Zhengzhou facility with batch-specific COA and SDS. For a technical discussion on grade selection or application-specific starting formulations, contact our technical team.
Molecular Weight Selection Guide
The choice of molecular weight determines the performance of PEI in your application. Use the table below to select the right grade.
| MW Grade | Typical Application | Key Property |
|---|---|---|
| 600 | Crosslinker, curing agent, small-molecule modification | High reactivity, low viscosity |
| 1,800 | Adhesion promoter, inks, coatings | Balanced reactivity and film formation |
| 10,000 | Flocculant, paper wet strength, dye fixation | Optimal charge density / MW balance |
| 70,000 | High-efficiency flocculation, biomedical transfection | High MW, strong bridging and transfection |
Not sure which grade fits your application? Send us your application details and we will recommend the right grade.
Key Features
High Cationic Charge Density
The amine groups give PEI a strong positive charge that neutralizes anionic particles, pigments, and metal ions.
Five MW Grades from One Source
600, 1,800, 10,000, 25,000 and 70,000. Same COA format, same QC standard across all grades.
Water-Soluble at All Concentrations
PEI mixes with water in any ratio and dissolves in ethanol, methanol, and other polar solvents.
No Formaldehyde. No Chlorine.
Suitable for paper and water treatment where residual chemicals are regulated.
Reactive Amine Groups
Primary and secondary amines react with epoxy, isocyanate, and carboxyl groups.
Chelating Ability
Forms stable complexes with heavy metal ions (zinc, zirconium, copper) through amine groups.
Applications
PEI is used in five major application areas. The recommended molecular weight grade varies by application.
💧 Water & Wastewater Treatment
PEI flocculates anionic particles - clay, silica, bacteria, and heavy metals - more effectively than polyamines or polyacrylamides in many systems. The high charge density neutralizes particle surfaces, then the polymer chain bridges them into large, fast-settling flocs.
Recommended grade: MW 10,000 or 70,000
🔗 Adhesion Promotion
PEI is used as a primer and adhesion promoter for inks, adhesives, and coatings. It improves bonding to difficult substrates like PET, nylon, and metals by forming a chemical bridge between substrate and functional layer.
Recommended grade: MW 600 or 1,800
📄 Paper Wet Strength
PEI is a formaldehyde-free wet-strength resin. It forms a crosslinked network between cellulose fibers, improving wet tensile strength by 30–50%. Unlike PAE, it does not contain chlorine or anionic residues.
Recommended grade: MW 10,000
🧬 Biomedical & Gene Delivery
Branched PEI (25 kDa) is the gold standard for non-viral gene delivery. Its proton-sponge effect enables endosomal escape, achieving high transfection efficiency in DNA and siRNA delivery.
Recommended grade: MW 25,000 or 70,000
🎨 Inks, Dyes & Pigment Dispersants
PEI acts as a cationic dispersant and fixation agent for pigments and dyes. It adsorbs onto negatively charged pigment surfaces and prevents agglomeration.
Recommended grade: MW 1,800 or 10,000
Product Specifications
| Item | Specification |
|---|---|
| Product Name | Polyethyleneimine (PEI) |
| Synonym | Polyaziridine; Ethyleneimine Polymer |
| CAS Number | 9002-98-6 |
| Molecular Formula | (C2H5N)n |
| Molecular Weight | 600 · 1,800 · 10,000 · 25,000· 70,000 |
| Appearance | Colorless to pale yellow, viscous liquid |
| Density (25°C) | 1.030 g/mL (pure PEI) |
| Amine Value | High (titration measured per batch) |
| Water Solubility | Fully soluble (100%, any ratio) |
| pH (5% aqueous, 25°C) | 10 – 12 |
| Viscosity (25°C) | Grade-dependent (200 – 150,000 mPa·s) |
| Softening Point | ~ 59–60°C (for solid grades) |
| Flash Point | > 110°C |
| Loss on Drying | ≤ 5.0% |
| Heavy Metals (as Pb) | ≤ 10 ppm |
| Residual Monomer | ≤ 0.1% (Aziridine-free) |
| Storage | 2–8°C, sealed container, protect from moisture |
| Shelf Life | 24 months (sealed, dry) |
| Packaging | 1 kg / 25 kg / 200 kg |
| Documents | COA, SDS with every batch |
COA & SDS Documentation
📄 COA Reports (Per Batch)
- Molecular Weight - GPC
- Amine Value - Titration (mmol/g)
- Appearance - Visual
- Density - 25°C
- Water Solubility - Qualitative
- pH (5% aqueous, 25°C)
Actual measured values for the specific lot. Not specification ranges.
📋 SDS Sections (GHS Format)
- Identification & Hazards
- Composition & First Aid
- Fire Fighting & Handling
- Storage & Exposure Control
- Physical Properties
- Stability, Toxicology, Disposal
SDS available in English, Chinese, and 40+ other languages.
Manufacturing & Quality Control
Molecular Weight
GPC Verified
Amine Value
Titration
Batch Retain
24 Months
COA Format
Actual Measured Values
Third-Party Inspection
SGS · BV on Request
Storage
2–8°C, Sealed
Every batch of PEI is tested for molecular weight distribution, amine value, and appearance before release. Batch-specific COA and SDS ship with every order. For a full QC report on a specific lot, contact our technical team.
Packaging & Shipping
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1 kg
Lab-scale sample
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25 kg
Standard drum
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200 kg
Bulk production
✈️
Express / Air / Sea
Samples dispatched in 3–7 days
PEI is classified as non-hazardous for transport. Standard packaging is in polyethylene drums or foil bags. Custom packaging is available on request. Each shipment includes COA, SDS, and packing list.
Why Choose Alfa Chemical
PEI is not a single specification product. The molecular weight you choose determines whether it works as a flocculant, an adhesion promoter, or a crosslinker. Here is what Alfa Chemical provides.
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Four MW Grades, One Source
600, 1,800, 10,000, and 70,000. All from the same facility, same COA format.
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Grade Selection Guidance
Tell us your application. We will recommend the MW grade and share a starting formulation.
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Sample-Scale to Bulk
1 kg for lab evaluation, 25 kg for pilot, 200 kg for production.
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COA Reports Actual Values
MW by GPC, amine value by titration. Measured numbers, not specification ranges.
Frequently Asked Questions
Which molecular weight should I use for water treatment?
For most wastewater flocculation, MW 10,000 or 70,000 works best. Higher MW gives stronger bridging between particles.
What is the difference between branched and linear PEI?
Branched PEI contains primary, secondary, and tertiary amines. Linear PEI contains only secondary amines. Branched PEI has higher charge density.
Is PEI soluble in solvents other than water?
Yes. PEI is soluble in water, ethanol, methanol, chloroform, and DMAC. Insoluble in non-polar solvents.
What parameters does the COA report?
Molecular weight (GPC), amine value (titration), appearance, density, pH, water solubility. Actual measured values.
What is the MOQ and lead time?
MOQ is 1 kg for evaluation. Stock items dispatch in 3–7 business days. Bulk orders typically 2–3 weeks.
How should PEI be stored?
Store in a sealed container at 2–8°C. Protect from moisture. Shelf life is 24 months.
Not sure which MW grade fits your application?
Tell us what you're formulating. We'll recommend the right grade and send a sample.
Related Resources
About Alfa Chemical
Alfa Chemical manufactures specialty chemicals in Zhengzhou, Henan, China. PEI is produced at our own facility in multiple molecular weight grades, with batch-specific COA and SDS for every order.
If you are working on a water treatment, paper, or coating formulation and need PEI, send us a note. Samples and technical support are available. Reach us through our Contact Us page, or browse our Organic Chemistry range.
All products are supplied for research and development use only. Not for human or veterinary use. Not for diagnostic, therapeutic, or drug use. COA and SDS are available with every shipment.
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