HYDROXYPROPYL METHYLCELLULOSE HPMC VS MC
Hydroxypropyl Methylcellulose is non-ionic cellulose mixed ether made from refined cotton by alkaline treatment and then by a series of reactions with propylene epoxide and methyl chloride as etherifying agents. The degree of substitution is generally 1.2-2.0. Its properties are varied depending on the difference of the proportion of methoxy content and hydroxy-propyl content.
1. Hydroxypropyl Methylcellulose is easily soluble in cold water but difficult to be soluble in hot water. However, its gelling temperature in hot water is significantly higher than that of Methyl Cellulose (MC). And compared with MC, the dissolution in cold water has also been greatly improved.
2. The viscosity of Hydroxypropyl Methylcellulose is related to the size of the molecular weight, and the larger the molecular weight is , the higher the viscosity is. The temperature will also affect its viscosity. As the temperature increases, the viscosity decreases. However, the viscosity of Hydroxypropyl Methylcellulose is less affected by the temperature than Methyl Cellulose, and its solution is stable in storage at room temperature.
3. Hydroxypropyl Methylcellulose has stability to acids and bases and its aqueous solution is very stable at pH 2-12. Caustic soda and lime water have little impact on its performance. but bases can accelerate its dissolution rate and slightly increase the viscosity. Hydroxypropyl Methylcellulose has the stability to general salts, but the Hydroxypropyl Methylcellulose solution viscosity will tend to increase when the concentration of the salt solution is high.
4. The water-retaining property of Hydroxypropyl Methylcellulose depends on its addition amount and viscosity. With the same addition amount, the water-retention rate of Hydroxypropyl Methylcellulose Hpmc is higher than that of MC.
5. Hydroxypropyl Methylcellulose can mix with water-soluble polymers and then form a uniform solution of higher viscosity, such as polyvinyl alcohol, starch ethers, and vegetable gums.
6. Hydroxypropyl Methylcellulose has higher adhesion on mortar construction than MC.
7. Hydroxypropyl Methylcellulose has better enzyme resistance than MC, and the possibility of enzymatic degradation of Hydroxypropyl Methylcellulose is less than that of MC.
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