What is hydroxyethyl methylcellulose?

alias: hydroxyethyl methyl cellulose; hydroxyethyl methyl cellulose; hydroxymethyl ethyl cellulose; 2-hydroxyethyl methyl ether cellulose
English aliases: Methylhydroxyethylcellulose; Cellulose; 2-hydroxyethyl methyl ether; HEMC; Tyopur MH[1]
Chemistry: Hydroymethylmethylcellulose; Hydroxyethylmethylcellulose; Hydroxymethylethylcellulose.
CAS Registration: 9032-42-2

Molecule: C2H6O2 xCH4O x PhEur 2002 defines hydroxyethyl methylcellulose as partially O-methylated, partially O-hydroxymethylated cellulose. Different specifications are expressed by the apparent viscosity value of 2% w/v aqueous solution at 20°C, and the unit is mPa s.
Molecular weight: PhEur 2002 defines hydroxyethyl methylcellulose as partially O-methylated, partially O-hydroxymethylated cellulose. Different specifications are expressed by the apparent viscosity value of 2% w/v aqueous solution at 20°C, and the unit is mPa s.

The main characteristics of hydroxyethyl methylcellulose (HEMC) are:

1. Solubility: Soluble in water and some organic solvents. HEMC can be dissolved in cold water. Its highest concentration is only determined by viscosity. Solubility varies with viscosity. The lower the viscosity, the greater the solubility.

2. Salt resistance: HEMC products are non-ionic cellulose ethers and are not polyelectrolytes, so they are relatively stable in aqueous solutions when metal salts or organic electrolytes exist, but excessive addition of electrolytes can cause gelation and precipitation.

3. Surface activity: Due to the surface active function of the aqueous solution, it can be used as a colloidal protective agent, emulsifier and dispersant.

4. Thermal gel: When the HEMC product aqueous solution is heated to a certain temperature, it becomes opaque, gels, and precipitates, but when it is continuously cooled, it returns to the original solution state, and the gel and precipitation occur. The temperature mainly depends on their lubricants, suspending aids, protective colloids, emulsifiers, etc.

5. Metabolic inertness and low odor and fragrance: HEMC is widely used in food and medicine because it will not be metabolized and has low odor and fragrance.

6. Mildew resistance: HEMC has relatively good mildew resistance and good viscosity stability during long-term storage.

7. PH stability: The viscosity of the aqueous solution of HEMC products is hardly affected by acid or alkali, and the pH value is relatively stable in the range of 3.0-11.0.
Application: Hydroxyethyl methylcellulose can be used as a colloidal protective agent, emulsifier and dispersant due to its surface active function in aqueous solution. Its application example is as follows: the influence of hydroxyethyl methylcellulose on the performance of cement. Hydroxyethyl methylcellulose is an odorless, tasteless, non-toxic white powder that can be dissolved in cold water to form a transparent viscous solution. It has the characteristics of thickening, binding, dispersing, emulsifying, film-forming, suspending, adsorbing, gelling, surface active, maintaining moisture and protecting colloid. Since the aqueous solution has a surface active function, it can be used as a colloidal protective agent, emulsifier and dispersant. Hydroxyethyl methylcellulose aqueous solution has good hydrophilicity and is an efficient water retention agent.