Cellulose ethers are a diverse group of derivatives obtained by chemically modifying natural cellulose, the main component of plant cell walls. The specific type of cellulose ether is determined by the nature of the chemical modifications introduced onto the cellulose backbone. Here are some common types of cellulose ethers, each with its unique properties and applications:

1. Methyl Cellulose (MC):
   • Chemical Modification: Introduction of methyl groups onto the cellulose backbone.
   • Properties and Applications:
     • Water-soluble.
     • Used in construction materials (mortars, adhesives), food products, and pharmaceuticals (tablet coatings).
2. Hydroxyethyl Cellulose (HEC):
   • Chemical Modification: Introduction of hydroxyethyl groups onto the cellulose backbone.
   • Properties and Applications:
     • Highly water-soluble.
     • Commonly used in cosmetics, personal care products, paints, and pharmaceuticals.
3. Hydroxypropyl Methyl Cellulose (HPMC):
   • Chemical Modification: Introduction of hydroxypropyl and methyl groups onto the cellulose backbone.
   • Properties and Applications:
     • Water-soluble.
     • Widely used in construction materials (mortars, coatings), pharmaceuticals, and food products.
4. Carboxymethyl Cellulose (CMC):
   • Chemical Modification: Introduction of carboxymethyl groups onto the cellulose backbone.
   • Properties and Applications:
     • Water-soluble.
     • Used as a thickener and stabilizer in food products, pharmaceuticals, textiles, and drilling fluids.
5. Hydroxypropyl Cellulose (HPC):
   • Chemical Modification: Introduction of hydroxypropyl groups onto the cellulose backbone.
   • Properties and Applications:
     • Water-soluble.
     • Commonly used in pharmaceuticals as a binder, film-forming agent, and thickener.
6. Ethyl Cellulose (EC):
   • Chemical Modification: Introduction of ethyl groups onto the cellulose backbone.
   • Properties and Applications:
     • Water-insoluble.
     • Used in coatings, films, and controlled-release pharmaceutical formulations.
7. Hydroxyethyl Methyl Cellulose (HEMC):
   • Chemical Modification: Introduction of hydroxyethyl and methyl groups onto the cellulose backbone.
   • Properties and Applications:
     • Water-soluble.
     • Commonly used in construction materials (mortars, grouts), paints, and cosmetics.

These types of cellulose ethers are chosen based on their specific properties and functionalities required for various applications. The chemical modifications determine the solubility, viscosity, and other performance characteristics of each cellulose ether, making them versatile additives in industries such as construction, pharmaceuticals, food, cosmetics, and more.