Cellulose ether & its derivatives

Cellulose ether is a kind of natural polymer compound, its chemical structure is anhydrous β -glucose as the base ring polysaccharide macromolecule, in each base ring has a primary hydroxyl and two secondary hydroxyl. Through chemical modification, a series of cellulose derivatives can be obtained, cellulose ether is one of them. Cellulose ether is made of cellulose with ether structure of polymer compounds, such as methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose and so on. It is generally obtained by the action of alkali cellulose with monochloroalkane, ethylene oxide, propylene oxide or monochloroacetic acid.

Performance and features

1. Physical features

Cellulose ether is generally white or milky white, tasteless, non-toxic, with fluidity of fibrous powder, easy to absorb moisture, dissolved in water into transparent viscous stable colloid.

2. Film forming and adhesion

The etherification of cellulose ether has great influence on its properties, such as solubility, film forming ability, bond strength and salt resistance. Cellulose ether has high mechanical strength, flexibility, heat resistance and cold resistance, and a variety of resins and plasticizers have good compatibility, can be used to manufacture plastics, film, varnish, adhesives, latex and drug coating materials.

3. The solubility

Methyl cellulose soluble in cold water, insoluble in hot water, but also soluble in some organic solvents; Methyl hydroxyethyl cellulose is soluble in cold water but insoluble in hot water and organic solvents. However, when the aqueous solution of methyl cellulose and methyl hydroxyethyl cellulose is heated, methyl cellulose and methyl hydroxyethyl cellulose will be precipitated. Methyl cellulose precipitates at 45 ~ 60℃, while the precipitation temperature of mixed etherized methyl hydroxyethyl cellulose increases to 65 ~ 80℃. As the temperature decreases, the precipitate redissolves. Hydroxyethyl cellulose and sodium carboxymethyl hydroxyethyl cellulose are soluble in water of any temperature and insoluble in organic solvents.

4. The thickening

Cellulose ether in colloidal form dissolved in water, its viscosity depends on the degree of polymerization of cellulose ether. The solution contains macromolecules of hydration. Because of the entanglement of macromolecules, the flow behavior of the solution is different from that of Newtonian fluid, but shows a behavior that changes with the shear force. Because of the macromolecular structure of cellulose ether, the viscosity of the solution increases rapidly with the increase of concentration, and decreases rapidly with the increase of temperature.

Application

1. Oil industry

Sodium carboxymethyl cellulose is mainly used in petroleum exploitation, used in the manufacture of mud, increase viscosity, reduce water loss effect, it can resist all kinds of soluble salt pollution, improve oil recovery rate. Sodium carboxymethyl hydroxypropyl cellulose (NaCMHPC) and sodium carboxymethyl hydroxyethyl cellulose (NaCMHEC) are good drilling mud treatment agents and materials for preparation of completion fluid. They have high slurry forming rate, good salt and calcium resistance, good viscosity increasing ability and temperature resistance (160℃). It can be used to prepare fresh water, sea water and saturated salt water drilling fluid. Under the condition of calcium chloride, it can be made into drilling fluid with various densities (103 ~ 127g/cm3), and it has certain viscosity and low filtration loss. Its viscosity and filtration loss loss ability are better than that of hydroxyethyl cellulose, so it is a good additive for oil production.

Sodium carboxymethyl cellulose is a cellulose derivative widely used in the process of petroleum exploitation. It is used in drilling fluid, cementing fluid, fracturing fluid and improving the amount of oil recovery, especially in the large amount of drilling fluid, the main effect of filtration and viscosity. Hydroxyethyl cellulose (HEC) is used as a mud thickening stabilizer in drilling, completion, and cementing processes. Because hydroxyethyl cellulose and sodium carboxymethyl cellulose, guar gum compared with good thickening effect, strong suspension sand, high salt capacity, good heat resistance, and small resistance, less liquid loss, broken glue block, residue and other characteristics, has been widely used.

2. Construction, coating industry

Building building and plastering mortar admixture sodium carboxymethyl cellulose can be used as a retarder, water retention agent, thickening agent and binder, can be used as plaster and cement bottom of the plaster, mortar and ground level material dispersant, water retention agent, thickening agent. A kind of aerated concrete block masonry and plastering mortar admixture made of carboxymethyl cellulose can improve the workability, water retention, crack resistance of mortar, avoid block wall cracking and hollow drum. Cao Minggan and other building surface decoration materials are made of methyl cellulose into an environment-friendly building surface decoration material. The production process is simple and clean. It can be used for high-grade wall surface, stone tile surface, as well as column and monument surface decoration.

3. Daily chemicals industry

Sodium carboxymethyl cellulose stabilizes viscosity stabilizing agent in solid powder paste products, and thickens, disperses and homogenizes cosmetics in liquid or emulsion. It can be used as a stabilizer and tackifier. Emulsification stabilizer to do ointment, shampoo emulsifier, tackifier and stabilizer. Sodium carboxymethyl hydroxypropyl cellulose can be used as adhesive stabilizer of toothpaste, with good thixotropic properties, so that the toothpaste has good formability, no deformation for a long time, and smooth taste. Sodium carboxymethyl hydroxypropyl cellulose salt resistance, acid resistance is superior, the effect is far better than carboxymethyl cellulose, can be used as detergent tackifier, dirt adhesion prevention agent. Dispersing thickener in detergent production, generally with sodium carboxymethyl cellulose as washing powder dirt dispersant, liquid detergent thickening agent and dispersant.

4. Medicine and food industry

In the pharmaceutical industry, hydroxypropyl carboxymethyl cellulose (HPMC) can be used as drug excipients, widely used in oral drug framework controlled release and sustained release preparations, as a release blocking material to regulate the release of drugs, as a coating material sustained release agent, sustained release pills, sustained release capsules. The most commonly used is methyl carboxymethyl cellulose, ethyl carboxymethyl cellulose, such as MC is often used to manufacture tablets and capsules, or coated sugar-coated tablets. High-quality grade cellulose ether can be used in the food industry, in a variety of food is an effective thickener, stabilizer, excifer, water retention agent and mechanical foaming agent. Methyl cellulose and hydroxypropyl methyl cellulose are recognized as metabolic inert substances that are harmless to physiology. High purity (99.5% +) carboxymethyl cellulose (CMC) can be added to food products, such as milk and cream products, condiments, jams, jelly, canned, table syrups and drinks. Purity of more than 90% of carboxymethyl cellulose can be used in food-related aspects, such as the application of fresh fruit transport and storage, this film has good preservation effect, less pollution, no damage, easy to mechanized production advantages.

5. Optical and electrical functional materials

Electrolyte thickening stabilizer due to the high purity of cellulose ether, good acid resistance, salt resistance, especially iron and heavy metal content is low, so the colloid is very stable, suitable for alkaline battery, zinc manganese battery electrolyte thickening stabilizer. Many cellulose ethers exhibit thermotropic liquid crystal properties. Hydroxypropyl cellulose acetate forms thermotropic cholesteric liquid crystal at temperatures below 164℃.