Sodium Carboxymethyl Cellulose (CMC): Versatile Polymer for Industrial & Consumer Applications

Technical Introduction

Sodium Carboxymethyl Cellulose (CMC) is a water-soluble anionic cellulose ether derived from natural cellulose. Through a carboxymethylation reaction, some hydroxyl groups (-OH) on the cellulose backbone are replaced by carboxymethyl groups (-CH₂-COOH), making the polymer soluble in water and imparting unique rheological properties.

• Chemical Name: Sodium Salt of Carboxymethyl Cellulose

• CAS Number: 9004-32-4

• Structure: Linear polymer of β-(1→4)-linked glucose units with carboxymethyl substitutions

• Degree of Substitution (DS): Typically 0.4 – 1.4 (average number of carboxymethyl groups per anhydroglucose unit)

• Form: White/off-white powder or granular solid

Key Functional Properties:

• Thickening and viscosity modification

• Water retention and moisture control

• Suspension stabilization and emulsification

• Film formation and binding

Applications

1. Food Industry (E466 – Food Additive)

• Ice cream → improves texture, prevents ice crystal growth

• Bakery products → moisture retention and softness

• Beverages → stabilizer and thickener

• Sauces, dressings → improves viscosity and mouthfeel

• Gluten-free products → structure and binding agent

2. Pharmaceuticals & Healthcare

• Tablet binder and disintegrant

• Oral suspensions stabilizer

• Toothpaste thickener and stabilizer

• Eye drops → lubricant for dry eyes

3. Cosmetics & Personal Care

• Creams and lotions → viscosity control and stability

• Shampoos and conditioners → thickening and moisture retention

• Skin care gels → smooth texture, non-greasy feel

4. Industrial Applications

• Paper Industry → surface sizing, improved strength and printability

• Textiles → printing thickener, warp sizing agent

• Oil Drilling → mud additive for fluid loss control and rheology modification

• Detergents → anti-redeposition agent, prevents soil from re-depositing on fabrics

✅ Advantages

• Non-toxic, biodegradable, and environmentally friendly

• Wide solubility range in cold or hot water

• Excellent compatibility with other hydrocolloids, gums, and surfactants

• High versatility in different industries (food, pharma, industrial)

• Cost-effective thickener compared to alternatives like xanthan gum or guar gum

• Customizable viscosity (low, medium, high viscosity grades available)

⚙️ Technical Specifications (Typical Parameters)

⚠️ Safety & Regulatory Notes

• Food & Pharma: Approved as safe by FDA (GRAS), EU (E466), JECFA.

• Toxicology: Non-toxic, non-carcinogenic, and non-irritating when used within regulatory limits.

• Environmental Safety: Biodegradable and eco-friendly polymer.

• Storage: Keep in sealed packaging, away from moisture, heat, and direct sunlight.

❓ FAQ

Q1: Is CMC natural or synthetic?
CMC is a semisynthetic derivative of natural cellulose, modified to be water-soluble.

Q2: What is the difference between CMC and regular cellulose?
Regular cellulose is insoluble in water, while CMC is chemically modified to be soluble and provide thickening, stabilizing, and binding properties.

Q3: Can CMC replace xanthan gum in food?
Yes, in some applications. CMC provides similar thickening, but xanthan gum offers better shear-thinning. Often, blends of CMC + xanthan gum are used for optimized texture.

Q4: Is CMC safe for daily use in toothpaste and cosmetics?
Yes. It is widely used in oral care and personal care as a safe, non-toxic thickener.

Q5: What determines the grade of CMC?
Mainly degree of substitution (DS) and viscosity, which are tailored for food, pharmaceutical, or industrial applications.