Questions about You Should Know about HPMCMarch 23rd 2023
Product name: hydroxyethyl methyl cellulose HEMC
English name: Hymetellose
Alias: methyl hydroxyethyl cellulose; MHEC,hydroxyethyl methyl cellulose ether;
hydroxymethyl ethyl cellulose; 2-hydroxyethyl methyl ether cellulose
English alias: Methylhydroxyethylcellulose; Cellulose; 2-hydroxyethyl methyl ether; HEMC; Tyopur MH
Chemistry: Hydroymethylmethylecellulose; Hydroxyethylmethylcellulose; Hydroxymethylethylcellulose.
Molecules: C2H6O2 xCH4O x PhEur 2002 defines hydroxyethylmethylcellulose as partially O-methylated, partially O-hydroxymethylated cellulose. The different specifications are expressed in terms of apparent viscosity in mPa s of a 2% w/v aqueous solution at 20°C.
Molecular weight: PhEur 2002 defines hydroxyethylmethylcellulose as partially O-methylated, partially O-hydroxymethylated cellulose. The different specifications are expressed in terms of apparent viscosity in mPa s of a 2% w/v aqueous solution at 20°C.
The main characteristics of hydroxyethyl methyl cellulose (HEMC) are:
1. Solubility: soluble in water and some organic solvents, HEMC can be dissolved in cold water, its maximum 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 in the presence of metal salts or organic electrolytes, they are relatively stable in aqueous solutions, but excessive addition of electrolytes can cause gelation and precipitation.
3. Surface activity: As the aqueous solution has surface activity function, it can be used as colloid 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 forms a precipitate, but when it is continuously cooled, it returns to the original solution state, and this gel and precipitation occur. The temperature depends mainly 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 is not metabolized and has low odor and fragrance.
6. Antifungal: HEMC has good antifungal ability and good viscosity stability during long-term storage.
7. PH stability: The viscosity of HEMC product aqueous solution is hardly affected by acid or alkali, and the pH value is relatively stable in the range of 3.0-11.0.
Application: Hydroxyethyl methyl cellulose can be used as colloid protective agent, emulsifier and dispersant due to the surface active function of aqueous solution. An example of its application is as follows: The effect of hydroxyethyl methyl cellulose on the properties of cement. Hydroxyethyl methylcellulose is an odorless, tasteless, nontoxic white powder that dissolves in cold water to form a clear, viscous solution. It has the properties of thickening, binding, dispersing, emulsifying, film-forming, suspending, adsorbing, gelling, surface-active, retaining moisture and protecting colloids. Due to the surface active function of the aqueous solution, it can be used as a colloid protective agent, an emulsifier and a dispersant. Hydroxyethyl methyl cellulose aqueous solution has good hydrophilicity and is a high-efficiency water-retaining agent.