Chitosan (CAS 9012-76-4) is a natural, biodegradable polysaccharide obtained by deacetylating chitin, the structural polymer of shrimp and crab shells. Its combination of biocompatibility, film formation, flocculation and antimicrobial activity makes it useful across water treatment, pharmaceuticals, cosmetics, food and agriculture. This guide covers its chemistry, production, specifications and applications.
1. What Is Chitosan?
Chitin is a long-chain polymer of N-acetylglucosamine; when most acetyl groups are removed, the resulting chitosan carries free amino groups (glucosamine units) that give it cationic character in acidic solution – unique among natural polysaccharides and the basis of most of its applications.
2. Chemistry and Key Properties
| Property | Typical value / behaviour |
|---|---|
| Source | Deacetylated chitin from shrimp/crab shells |
| DAC (degree of deacetylation) | 90% min (food/pharma grades) |
| Solubility | Soluble in dilute acids (acetic, lactic); insoluble in water and alkali |
| Cationic charge | Positive in acidic media (protonated amino groups) |
| Appearance | Off-white to light yellow powder |
| Viscosity | Grade-dependent (low to high mPa.s at 1%) |
Key quality parameters on a COA: DAC degree, viscosity, moisture, ash, pH, acid-insoluble substance, heavy metals (As/Pb/Hg/Cd) and microbiology (total plate, yeast/mold, E. coli, Salmonella, S. aureus).
3. Production Technology
Commercial chitosan is made from crustacean shells in two stages:
- Chitin isolation: shells are demineralized (acid), deproteinized (alkali) and decolorized to give chitin.
- Deacetylation: chitin is treated with concentrated NaOH at elevated temperature (100-140 °C) to remove acetyl groups; reaction time and temperature control the DAC degree and molecular weight (viscosity).
Washing, drying and milling give the final powder. For sterile applications, an irradiation step (gamma or e-beam) produces irradiated grade; otherwise the non-irradiated grade is supplied.
4. Specifications and Grades
PolyblueChem supplies both irradiated and non-irradiated chitosan. Non-irradiated specification highlights: DAC 90% min, viscosity 200 mPa.s max, moisture 10% max, ash 1.5% max, pH 6.5-8.5, acid-insoluble substance 1.0% max, As/Pb/Hg/Cd each 0.5 ppm max, heavy metals 10 ppm max, total plate count 5000 cfu/g max, yeast & mold 100 cfu/g, E. coli/Salmonella/S. aureus negative.
5. Applications Overview
- Water treatment – coagulant/flocculant, heavy-metal and dye adsorbent.
- Pharmaceuticals and nutraceuticals – excipient, wound-care material, weight-management ingredient.
- Cosmetics and personal care – film-forming, moisturizing, antimicrobial.
- Food – clarifying, antimicrobial coating, dietary fiber.
- Agriculture – seed coating, soil amendment, plant defense elicitor.
6. Application Details
6.1 Water treatment
Chitosan’s cationic charge neutralizes negatively charged suspended particles and provides flocculation across a wide pH range; it also chelates heavy metals. It is used as a bio-coagulant replacing or supplementing inorganic salts in drinking-water and wastewater polishing.
6.2 Pharmaceutical and nutraceutical
As an excipient it is film-forming and mucoadhesive; in nutraceuticals it binds dietary fat (weight-management) and cholesterol. Irradiated grade meets sterility requirements for medical applications.
6.3 Cosmetics
Its film-forming and moisturizing behaviour suits skin-care and hair-care products; the antimicrobial character supports preservative-system relief.
7. Industry Landscape
Major chitosan producers are in Asia (China, India, Japan), with Western suppliers focusing on pharmaceutical and specialty grades. Buyers should compare DAC, viscosity and microbiological data, and confirm whether irradiated or non-irradiated grade is required for the end use.
8. Buying Guide
- Specify grade: DAC, viscosity range, irradiated or non-irradiated.
- Request COA with heavy metals and microbiology per batch.
- Confirm particle size and packaging (25 kg drums/bags).
- For pharma/medical use, request the irradiated grade and related documentation.
9. Safety and Handling
- Low toxicity, biodegradable; dust may irritate eyes/respiratory tract – use dust mask and goggles.
- Keep dry; the powder absorbs moisture and can hydrolyze/ degrade if exposed.
10. FAQ
What is the difference between irradiated and non-irradiated chitosan?
Irradiated grade is sterilized (gamma/e-beam) for pharmaceutical and medical use; non-irradiated is for food, cosmetic, water and general applications. Both are available.
Why does DAC matter?
Higher DAC gives better acid solubility and higher positive charge, improving performance in flocculation, antimicrobial and film applications.
11. References and Further Reading
- PubChem entry for chitosan (CID via PubChem REST API).
- Supplier COA and MSDS for the specific grade quoted.
This article is published for industrial and technical reference by PolyblueChem. Verify all values against the supplier’s COA and applicable standards before specification.
PolyblueChem supplies chitosan (CAS 9012-76-4) in irradiated and non-irradiated grades with COA and MSDS. Contact us for specifications and quotations.