Hydroxyethyl methylcellulose (HEMC) is a nonionic cellulose ether, which is a modified product obtained by partially hydroxyethylating methylcellulose (MC). HEMC has many unique physical and chemical properties, which makes it widely used in construction, medicine, food and other fields.

1. Solubility and solubility
HEMC has good solubility in water. It can quickly dissolve in cold water to form a transparent or translucent solution, and within a certain concentration range, its solution exhibits viscous properties. The aqueous solution of HEMC has pseudoplasticity, that is, as the shear rate increases, the viscosity of the solution decreases. This property makes it excellent in applications such as architectural coatings and adhesives.

2. Thickening
HEMC has excellent thickening properties and can effectively increase the viscosity of water-based systems. Its thickening effect is not only related to the molecular weight, but also to factors such as the concentration, pH value and temperature of the solution. HEMC is widely used in building materials such as cement mortar and gypsum-based materials because of its mild thickening effect and its low tendency to cause gelation of the system.

3. Water retention
HEMC has good water retention properties, which makes it an important additive in building materials. It can retain moisture in cement-based materials, prolong their open time, and improve the operability and construction properties of the materials. In addition, the water retention properties of HEMC also make it widely used in coatings, adhesives and food industries, which can prevent the water in the system from evaporating too quickly.

4. Film-forming properties
HEMC can form a uniform film on the surface with good film-forming properties. This film has certain strength and toughness, and can be used to protect the coating and prevent water penetration. The film-forming properties make it have important applications in coatings, paints, coating agents and other fields.

5. Stability
HEMC has stable chemical properties and good tolerance to acid and alkali environments. Its aqueous solution remains stable in a wide pH range (usually 2-12) and is not prone to gelation or precipitation. In addition, HEMC also has a certain stability to light, heat and oxidation, so that it can still work under harsh conditions.

6. Biocompatibility and safety
HEMC is a non-ionic compound that usually does not cause allergies or other adverse reactions and has good biocompatibility. Therefore, in the fields of medicine and food, HEMC is often used as a thickener, stabilizer and capsule material. Its safety makes it widely used in skin care and personal care products.

7. Salt resistance
Compared with other types of cellulose ethers, HEMC has better tolerance to electrolytes. It can still maintain good viscosity and stability in systems containing high concentrations of salt. This feature gives it advantages in some special applications, such as as a drilling fluid additive in oil field exploitation.

8. Lubricity and suspension
HEMC solutions have good lubricity and suspension, which can improve the fluidity and uniformity of construction. This is especially important in cement-based materials, which can improve the workability and anti-sagging properties of the material.

Hydroxyethyl methylcellulose is widely used in building materials, medicine, food, cosmetics and other fields due to its excellent thickening, water retention, film-forming and stability. Its non-ionic properties, good biocompatibility and stability make it a multifunctional additive that can play an important role in a variety of industrial applications.