Polyanionic Cellulose PAC CAS 9000-11-7

Polyanionic Cellulose (PAC)

Polyanionic Cellulose (PAC) is a water-soluble anionic polymer derived from the chemical modification of natural cellulose. Widely used in oil drilling, construction materials, food, and pharmaceutical industries, PAC is valued for its exceptional thickening, suspension, salt tolerance, and thermal stability properties.

1. Chemical Structure & Modification

• Base Structure: Cellulose backbone (β-1,4-glucan units) substituted with anionic groups (e.g., carboxymethyl, sulfonic acid).
• Degree of Substitution (DS): Typically 0.8-1.5 (number of hydroxyl groups substituted per glucose unit). Higher DS enhances water solubility and electrolyte resistance.

2. Physical & Chemical Properties

3. Functional Characteristics

• Thickening & Rheology Control: Forms a 3D network to enhance viscosity and improve suspension.
• Salt Tolerance: Stable in high-electrolyte environments (e.g., brine, Ca²/Mg²), resistant to flocculation.
• Filtration Control (drilling fluids): Forms low-permeability filter cakes to reduce fluid loss.
• Eco-friendliness: Biodegradable (slower degradation than CMC).

4. Key Applications

1. 1.Oil Drilling Fluids:
   • Acts as a viscosifier and fluid loss control agent in high-temperature/high-salinity conditions (e.g., shale gas, deep-well drilling).
2. 2.Construction Materials:
   • Additive in cement/mortar to improve water retention, workability, and anti-settling properties.
3. 3.Food Industry:
   • Food-grade PAC (E469) as a stabilizer/thickener (e.g., dairy products, ice cream).
4. 4.Pharmaceuticals & Cosmetics:
   • Tablet binder or emulsion stabilizer (shampoos, skincare products).

5. Technical Specifications (Typical Industrial Grade)

• DS (Degree of Substitution): ≥0.9
• Purity: ≥90%
• Moisture: ≤10%
• Particle Size: ≥90% passing 80 mesh
• CAS No.: 9000-11-7 (general for cellulose derivatives; specific functional groups may vary)

6. Safety & Storage

• Toxicity: Low toxicity; dust inhalation may irritate the respiratory tract (use dust masks).
• Storage:
  • Keep sealed in a dry, cool place (<30°C).
  • Shelf life: 24 months (under dry conditions).
• Regulatory Compliance:
  • Industrial grades: API 13A standards.
  • Food grades: FDA 21 CFR §182.1745.

7. Comparison with CMC

Note: Performance varies by application (e.g., drilling fluid salinity, temperature). Laboratory testing is recommended for optimal grade selection.