What is CMC in the chemical industry?

In the chemical industry, CMC (Carboxymethyl Cellulose Sodium) is also referred to as CMC. CMC is an important cellulose derivative obtained by chemically modifying natural cellulose. Specifically, the molecular structure of CMC is that carboxymethyl groups are introduced into the cellulose molecule, which gives it many new physical and chemical properties, so it is widely used in chemical, food, medicine and other industries.

1. Chemical structure and properties of CMC
CMC is a cellulose ether compound obtained by the reaction of cellulose and chloroacetic acid, and its basic structural unit is β-1,4-glucose ring. Unlike natural cellulose, carboxymethyl groups are introduced into the molecular structure of CMC, which enables it to form a viscous colloidal solution in water. The molecular weight of CMC can be adjusted according to the degree of reaction, and CMCs of different molecular weights show different solubility and viscosity in application. The solubility and viscosity of CMC are affected by the degree of substitution (that is, the number of substituents on the cellulose molecule). CMC with a high degree of substitution usually has higher water solubility and viscosity. CMC has high chemical stability, has a certain tolerance to acid and alkali environments, is non-toxic and harmless, and meets environmental protection and health standards.

2. CMC production process
The production process of CMC includes three steps: alkalization, etherification and post-treatment.

Alkalization: Cellulose (usually from natural materials such as cotton and wood pulp) is treated with sodium hydroxide to enhance the hydroxyl activity of cellulose, which is convenient for subsequent reactions.
Etherification: Sodium chloroacetate is added to the alkalized cellulose, and carboxymethyl groups are introduced through the reaction to convert cellulose into carboxymethyl cellulose.
Post-treatment: The CMC generated by the reaction is neutralized, filtered, dried and crushed to finally obtain products of different specifications. The degree of substitution and molecular weight of the product can be adjusted by controlling the reaction conditions, raw material concentration and reaction time, so as to obtain CMC products with different viscosities and solubility properties.

3. Performance characteristics of CMC
As a highly efficient thickener, stabilizer, film former and adhesive, CMC has the following performance characteristics:

Good water solubility: CMC is easily soluble in water and can form a transparent colloidal solution, and the dissolution process is gentle and easy to operate.
Strong thickening effect: CMC can significantly increase the viscosity of the solution at a lower concentration, which makes it have high application value in many occasions where thickening effects are required.
Stability: CMC has high tolerance to acid, alkali, light, heat, etc., and has good solution stability.
Safe and non-toxic: CMC is widely used in food, medicine and other industries. It is safe and non-toxic and suitable for direct or indirect food contact materials.

4. Application fields of CMC
Food industry: CMC is widely used as a thickener, emulsifier, stabilizer, etc. in the food industry. It can be used in ice cream, jam, condiments, beverages, dairy products, etc. to effectively improve the texture, taste and stability of food. For example, CMC as a thickener in ice cream can effectively prevent the formation of ice crystals and make the taste of ice cream smoother.

Pharmaceutical industry: In the pharmaceutical field, CMC can be used as an adhesive for tablets, a matrix for ointments, and a thickener for some liquid drugs. CMC also has certain adhesion and film-forming properties, which can improve the controlled release effect of drugs and improve the stability and absorption rate of drugs.

Daily chemical industry: In cosmetics and personal care products, CMC is widely used in lotions, creams, shampoos and other products as a thickener and stabilizer. CMC’s good water solubility and film-forming properties enable it to stabilize the structure of cosmetics and improve the softness of the product.

Petroleum industry: CMC plays the role of thickener and filtration agent in drilling fluid, fracturing fluid and cement slurry, effectively reducing the risk of liquid loss and blockage during drilling, and improving drilling efficiency and safety.

Textile and papermaking industry: CMC can be used as a yarn sizing agent, textile finishing agent and paper additive in the textile and papermaking fields, which can improve yarn strength and improve the water resistance and tensile strength of paper.

5. Market demand and development prospects of CMC
With the rapid development of the global economy and technological advancement, the market demand for CMC is growing. Especially in the food and pharmaceutical industries, as consumers pay more attention to health and safety, the natural and harmless thickener CMC has gradually replaced some synthetic chemicals. In the future, the demand for CMC market is expected to continue to expand, especially in the application prospects of food thickeners, drilling fluids, drug controlled release carriers, etc.

Since the raw material source of CMC is mainly natural cellulose, the production process is relatively environmentally friendly. In order to cater to the development trend of green chemical industry, the CMC production process is also constantly improving, such as reducing pollution emissions in the production process, improving resource utilization, etc., and strive to make the production of CMC meet the goal of sustainable development.

As an important cellulose derivative, sodium carboxymethyl cellulose (CMC) has been widely used in many industries such as chemical, food, medicine, daily chemicals, petroleum, textile and papermaking due to its unique water solubility, thickening and good stability. With the advancement of technology and the increase in market demand, the production process and application fields of CMC are constantly expanding, and it has important development potential in the fields of green chemical industry and high-performance applications in the future.