Overview
Cellulose is a natural polymer composed of anhydrous β-glucose units, and it has three hydroxyl groups on each base ring. By chemically modifying cellulose, a variety of cellulose derivatives can be produced, and one of them is cellulose ether. Cellulose ether is a polymer compound with an ether structure derived from cellulose, including methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose, and others. These derivatives are usually produced by reacting alkali cellulose with monochloroalkane, ethylene oxide, propylene oxide, or monochloroacetic acid. The resulting cellulose ether has excellent water solubility, thickening ability, and film-forming properties, and it is widely used in industries such as construction, pharmaceuticals, food, and cosmetics. Cellulose ether is a renewable, biodegradable, and non-toxic material, making it a popular alternative to synthetic polymers.
Performance and Features
1. Appearance Features
Cellulose ether is a white, odorless, fibrous powder that easily absorbs moisture and forms a stable, viscous, transparent colloid when dissolved in water.
2. Film Formation and Adhesion
The chemical modification of cellulose to produce cellulose ether significantly impacts its properties, including its solubility, film-forming ability, bond strength, and salt resistance. These characteristics make cellulose ether a highly desirable polymer with excellent mechanical strength, flexibility, heat resistance, and cold resistance. Additionally, it exhibits good compatibility with various resins and plasticizers, making it suitable for use in the production of plastics, films, varnishes, adhesives, latex, and drug coating materials. Due to its versatile properties, cellulose ether has become an important material in the manufacturing industry, providing improved performance, stability, and durability to a wide range of products. As a result, it has a broad range of applications in various fields, including pharmaceuticals, coatings, textiles, construction, and food industries, among others.
3. Solubility
The solubility of cellulose ethers such as methylcellulose, methyl hydroxyethyl cellulose, hydroxyethyl cellulose, and sodium carboxymethyl hydroxyethyl cellulose varies depending on the temperature and solvent used. Methylcellulose and methyl hydroxyethyl cellulose are soluble in cold water and some organic solvents but precipitate when heated, with methylcellulose precipitating at 45-60°C and the mixed etherified methyl hydroxyethyl cellulose at 65-80°C. However, the precipitates can redissolve when the temperature is lowered. On the other hand, hydroxyethyl cellulose and sodium carboxymethyl hydroxyethyl cellulose are water-soluble at any temperature but insoluble in organic solvents. These cellulose ethers have different solubility and precipitation properties that make them suitable for various applications in industries such as plastics, films, coatings, and adhesives.
4. Thickening
When cellulose ether dissolves in water, it forms a colloidal solution whose viscosity is influenced by the degree of polymerization of the cellulose ether. The solution contains hydrated macromolecules which exhibit non-Newtonian behavior, i.e., the flow behavior changes with the shear force applied. Due to the macromolecular structure, the viscosity of the solution increases quickly with concentration, but decreases rapidly with temperature increase. The viscosity of cellulose ether solutions is also influenced by pH, ionic strength, and the presence of other chemicals. These unique properties of cellulose ether make it useful in various applications such as adhesives, coatings, cosmetics, and food products.
Application
1. Petroleum Industry
Sodium carboxymethyl cellulose (NaCMC) is a cellulose ether with a wide range of applications in the oil extraction process. Its excellent viscosity-increasing and fluid loss reducing properties make it a popular choice in drilling fluids, cementing fluids, and fracturing fluids. In particular, it has shown promising results in improving oil recovery. NaCMC can resist various soluble salt pollution and increase oil recovery by reducing water loss, and its salt resistance and viscosity-increasing ability make it ideal for preparing drilling fluids for fresh water, sea water, and saturated salt water.
Sodium carboxymethyl hydroxypropyl cellulose (NaCMHPC) and sodium carboxymethyl hydroxyethyl cellulose (NaCMHEC) are two cellulose ether derivatives with high slurrying rate, good anti-calcium performance, and good viscosity-increasing ability, making them excellent choices as drilling mud treatment agents and materials for preparing completion fluids. They exhibit superior viscosity-increasing ability and fluid loss reducing properties compared to hydroxyethyl cellulose, and their ability to be formulated into drilling fluids of various densities under the weight of calcium chloride makes them a versatile additive for increasing oil production.
Hydroxyethyl cellulose (HEC) is another cellulose derivative used as a mud thickening and stabilizing agent in the drilling, completion, and cementing process. Compared to sodium carboxymethyl cellulose and guar gum, HEC has strong sand suspension, high salt capacity, good heat resistance, low mixing resistance, less liquid loss, and gel breaking block. HEC has been widely used due to its good thickening effect, low residue, and other properties. Overall, cellulose ethers like NaCMC, NaCMHPC, NaCMHEC, and HEC play critical roles in the oil extraction process and have shown significant potential in improving oil recovery.
2. Construction and Paint Industry
Sodium carboxymethyl cellulose is a versatile building material additive that can be used as a retarder, water retention agent, thickener and binder for building masonry and plastering mortar. It can also be used as a dispersant, water retaining agent and thickener for plaster, mortar and ground leveling materials. A special masonry and plastering mortar admixture made of carboxymethyl cellulose can improve workability, water retention and crack resistance, avoiding cracking and voids in the block wall. In addition, methyl cellulose can be used to make environmentally friendly building surface decoration materials for high-grade wall and stone tile surfaces, as well as for the surface decoration of columns and monuments.
3. Daily Chemical Industry
Sodium carboxymethyl cellulose is a versatile stabilizing viscosifier that can be used in a variety of products. In paste products containing solid powder raw materials, it plays a critical role in dispersion and suspension stabilization. For liquid or emulsion cosmetics, it functions as a thickening, dispersing, and homogenizing agent. This cellulose derivative can also act as an emulsion stabilizer, ointment and shampoo thickener and stabilizer, toothpaste adhesive stabilizer, and detergent thickener and anti-stain agent. Sodium carboxymethyl hydroxypropyl cellulose, a type of cellulose ether, is widely used as a toothpaste stabilizer due to its thixotropic properties, which helps maintain toothpaste formability and consistency. This derivative is also resistant to salt and acid, making it an effective thickener in detergents and anti-stain agents. Sodium carboxymethyl cellulose is commonly used as a dirt dispersant, thickener, and dispersant in the production of washing powder and liquid detergents.
4. Medicine and Food Industry
In the pharmaceutical industry, Yibang hydroxypropyl carboxymethylcellulose (HPMC) is widely used as a drug excipient for oral drug controlled release and sustained release preparations. It acts as a release retarding material to regulate the release of drugs, and as a coating material to delay the release of formulations. Methyl carboxymethyl cellulose and ethyl carboxymethyl cellulose are commonly used to make tablets and capsules, or to coat sugar-coated tablets. In the food industry, premium grade cellulose ethers are effective thickeners, stabilizers, excipients, water retaining agents and mechanical foaming agents in various foods. Methylcellulose and hydroxypropylmethylcellulose are considered metabolically inert and are safe for consumption. High-purity carboxymethylcellulose can be added to food products, including milk and cream, condiments, jams, jelly, canned food, table syrup, and beverages. Additionally, carboxymethyl cellulose can be used in the transportation and storage of fresh fruits as a plastic wrap, providing a good fresh-keeping effect, less pollution, no damage, and easy mechanized production.
5. Optical and Electrical Functional Materials
The high-purity cellulose ether with good acid and salt resistance acts as an electrolyte thickening stabilizer, providing stable colloidal properties for alkaline and zinc-manganese batteries. Some cellulose ethers display thermotropic liquid crystallinity, such as hydroxypropyl cellulose acetate, which forms cholesteric liquid crystals below 164°C.
Main Reference
● Dictionary of Chemical Substances.
● Characteristics, preparation and industrial application of cellulose ether.
● Status Quo and Development Trend of Cellulose Ether Market.
