Hydroxypropyl starch ether (HPS) is a non-ionic, water-soluble polymer obtained by chemically modifying natural starch. The hydroxyl groups (-OH) on the glucose units of the starch in its molecular structure undergo an etherification reaction with propylene oxide, introducing hydroxypropyl groups (-CH₂-CHOH-CH₃), thus obtaining a modified starch with excellent properties such as cold water solubility, good thickening properties, strong water retention, and high acid and alkali stability.
Main Characteristics
Physical Properties
Appearance: White, fine powder, easily hygroscopic; aqueous solution is transparent and colorless.
Wide viscosity range (500–20000 mPa·s, 5% aqueous solution, 20℃), pH value: 8–10.5 (2% aqueous solution).
Cold water soluble; gelatinization temperature is lower than that of native starch; stable viscosity under cold and hot conditions; good freeze-thaw stability.
Chemical Stability
Stable to acids and alkalis, highly resistant to salts and calcium and magnesium ions, and insensitive to high-valence cations.
Viscosity is unaffected when coexisting with salt, sucrose, etc.
Degree of Substitution (DS)
Typically 0.1–0.3; higher degree of substitution indicates stronger water solubility.
Core Uses:
Food Industry: Used as a thickener, suspending agent, and binder in ice cream, dairy products, etc., in appropriate amounts as required by production (as specified in GB2760).
Building Materials: Used in dry mortars, putties, tile adhesives, etc., to improve workability, anti-sagging properties, and open time; often used in combination with cellulose ethers.
Pharmaceutical Industry: Can be used as a tablet disintegrant or plasma expander.
Oil Extraction: Used as a drilling fluid treatment agent, with functions such as reducing fluid loss, stabilizing the wellbore, and resisting salt contamination.
Daily chemicals and papermaking: Used as a thickener and suspending agent in cosmetics and coatings; improves ink adhesion and surface smoothness in paper sizing.
