1) Appearance: HPMC is a nonionic cellulose ether, white grayish-white powder or granule,odorless and flavorless, soluble in cold water, glacial acetic acid, ethanol, methanol and propylene glycol, slightly soluble in acetone depending on the degree of substitutions, practically insoluble in hot water, ethylene glycol and toluene. HPMC is dissolved in a mixture of 10% methanol and 90% methylene chloride to form colloidal solutions.
2) The solution of HPMC has surface activity, high transparency, and stable performance. When heated at certain temperature, the solution becomes cloudy or forms flocculent gel. However, the solution becomes clear again after cooling. Different types of HPMC have different gelation temperatures. The solubility varies with the viscosity. The lower the viscosity, the higher solubility it has. The different types of HPMC are different in some properties and their solubility in water is not affected by pH.
3) Particle sizes: 100% pass rate in 80 mesh.
4) Apparent density: 0.25-0.70 g/mL (usually about 0.5 g/mL),specific density 1.26-1.31mL.
5) Color change temperature:190-200°C; Carbonization temperature:280-300°C.
6) Surface tension:42-56 dyn/cm (2% aqueous solution).
7) The higher methoxy content in HPMC, the lower gelation temperature, and the higher solubility in water and surface activity.
8) HPMC has some other characteristics, for example, thickening property, pH stability, retention of water, excellent film-forming property, good disperse and adhesion ability.