What is the pH value of hydroxyethyl cellulose?

Hydroxyethyl Cellulose (HEC) is a non-ionic water-soluble polymer compound widely used in architectural coatings, daily chemical products, oil field drilling, pharmaceuticals and other industries. It is mainly used as a thickener, emulsifier, stabilizer and film-forming agent.

pH value of hydroxyethyl cellulose

Hydroxyethyl cellulose itself is neutral or weakly acidic, but its pH value usually refers to the pH range of its aqueous solution, not the pH value of its solid state. Generally speaking, the pH value of 1% to 2% hydroxyethyl cellulose aqueous solution ranges from 6.0 to 8.5, depending on the purity of the product, the dissolving medium and the chemical treatment during the manufacturing process.

Factors affecting pH value

Product purity

Industrial grade and high-purity HEC may have a small amount of different acidic or alkaline residues that affect the pH value.

Dissolving medium

If the water source contains impurities or buffer solution components, it will cause changes in pH. For example, tap water may contain calcium and magnesium ions or other alkaline substances, which may slightly increase the pH value.

Production process

Different manufacturers use different degrees of etherification and washing processes, which may cause slight changes in pH.

Formulation system

In practical applications, HEC is often used in combination with other ingredients (such as alkaline thickeners and acidic stabilizers), and the pH value of the overall system will be affected. For example, in the coatings industry, HEC is often used with alkaline additives (such as ammonia water) to adjust the pH value to a suitable range (usually between 7.5 and 9.5).

pH adjustment

If the pH value of HEC aqueous solution needs to be adjusted, the following methods can be adopted:

Increase pH value: Add sodium carbonate (Na₂CO₃), sodium hydroxide (NaOH) or ammonia water (NH₄OH), but it should be added gradually to prevent over-alkalization.

Lower pH value: Acidic substances such as dilute hydrochloric acid (HCl) or citric acid can be added, but they should be carefully controlled to avoid adverse effects on the solubility of HEC.

pH control in application

Coating industry: In latex paint, the thickening effect of HEC is less affected by pH value, but the system pH value is usually maintained between 7.5 and 9.0 to maintain the stability of the emulsion.

Daily chemical industry: Such as shampoo, hand sanitizer, etc., the pH value of HEC is usually maintained between 5.5 and 7.5 to adapt to the acid-base balance of the skin.

Oilfield drilling: When HEC is used in drilling fluid, the pH value is generally controlled at 7.0-10.0 to ensure rheological properties and salt resistance.

The pH value of hydroxyethyl cellulose mainly depends on the concentration of its aqueous solution, dissolution medium and formulation system, usually between 6.0 and 8.5. In actual applications, according to different industry requirements, the pH value may need to be adjusted to ensure its optimal performance.