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Which is better CMC or HPMC?

Author: May

Aug. 06, 2024

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Carboxymethyl cellulose - Wikipedia

Cellulose derivative grafted with carboxymethyl groups

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Chemical compound

Carboxymethyl cellulose (CMC) or cellulose gum[1] is a cellulose derivative with carboxymethyl groups (-CH2-COOH) bound to some of the hydroxyl groups of the glucopyranose monomers that make up the cellulose backbone. It is often used in its sodium salt form, sodium carboxymethyl cellulose. It used to be marketed under the name Tylose, also a registered trademark of SE Tylose.[2]

Preparation

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Carboxymethyl cellulose is synthesized by the alkali-catalyzed reaction of cellulose with chloroacetic acid.[3] The polar (organic acid) carboxyl groups render the cellulose soluble and chemically reactive.[4] Fabrics made of cellulose&#;e.g., cotton or viscose rayon&#;may also be converted into CMC.[5]

Following the initial reaction, the resultant mixture produces approximately 60% CMC and 40% salts (sodium chloride and sodium glycolate). This product, called technical CMC, is used in detergents.[citation needed] An additional purification process is used to remove salts to produce pure CMC, which is used for food and pharmaceutical applications.[6] An intermediate "semi-purified" grade is also produced, which is typically used in paper applications such as the restoration of archival documents.[7]

Structure and properties

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Structure

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CMC is a derivative of the regenerated cellulose [C6H10O5]n with hydroxy-acetic acid (hydroxy ethanoic acid) CH2(OH)COOH or sodium monochloroacetate ClCH2COONa. The CMC backbone consists of D-glucose residues linked by -1,4-linkage. It has carboxymethyl groups (-CH2-COOH) bound to some of the hydroxyl groups of the glucopyranose monomers that make up the cellulose backbone. It is often used as its sodium salt, sodium carboxymethyl cellulose.[8]

Properties

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CMC is a white or lightly yellow powder with no odor, flavor, or poisonous properties. It is hygroscopic and dissolves well in hot or cold water, forming a viscous solution. It is not soluble in organic solvents like methanol, ethanol, acetone, chloroform, and benzene. The functional properties of CMC depend on the degree of substitution of the cellulose structure (i.e., how many of the hydroxyl groups have been converted to carboxymethylene groups in the substitution reaction), as well as the chain length of the cellulose backbone structure and the degree of clustering of the carboxymethyl substituents. It is commonly used as a viscosity modifier or thickener, and to stabilize emulsions in various products, both food and non-food-related. It is mainly used because it has a high viscosity, is nontoxic, and is generally considered to be hypoallergenic.[8]

Uses

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Introduction

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Carboxymethyl cellulose (CMC) is used in applications ranging from food production to medical treatments.[9] It is commonly used as a viscosity modifier or thickener and to stabilize emulsions in both food and non-food products. It is used primarily because it has high viscosity, is nontoxic, and is generally considered to be hypoallergenic, as the major source fiber is either softwood pulp or cotton linter. It is also used in non-food products which include products such as toothpaste, laxatives, diet pills, water-based paints, detergents, textile sizing, reusable heat packs, various paper products, filtration materials, synthetic membranes, wound healing applications, and also in leather crafting to help burnish edges.[10][11][12][verification needed]

Food science

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CMC is registered as E466 or E469 (when it is enzymatically hydrolyzed). It is used for a viscosity modifier or thickener and to stabilize emulsions in various products, including ice cream, mayonnaise, and beverages. It is also used extensively in gluten-free and reduced-fat food products.[13]

CMC's variable viscosity (high while cold, and low while hot) makes it useful in the preparation of cold foods and textures in beverages and edible gels. With a DS around 1.0, it can prevent dehydration and shrinkage of gelatin while also contributing to a more airy structure. In some foods, it can be used to control oil and moisture content.[14]

CMC is used to achieve tartrate or cold stability in wine, which can prevent excess energy usage while chilling wine in warm climates. It is more stable than metatartaric acid and is very effective in inhibiting tartrate precipitation. It is reported that KHT crystals, in the presence of CMC, grow slower and change their morphology.[15][non-primary source needed][16][17][better source needed] Their shape becomes flatter because they lose 2 of the 7 faces, changing their dimensions. CMC molecules, negatively charged at wine pH, interact with the electropositive surface of the crystals, where potassium ions are accumulated. The slower growth of the crystals and the modification of their shape are caused by the competition between CMC molecules and bitartrate ions for binding to the KHT crystals.[18][17][full citation needed]

Food fraud

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  • Shrimp and prawns: CMC injections have been used to fraudulently increase the weight and visual appeal of shrimp and prawns so as to short-weight customers.[19]

Detergent uses

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CMC is a common ingredient in cleaning products because of its thickening and stabilizing properties and nontoxic composition. In detergent and cleaning products, it can be used to enhance texture and assist in the suspension of dirt and grime in the cleaning product. Its adjustable viscosity can be used to standardize the textures of the products, especially when used along with other chemicals.

CMC helps with the removal of grease and aids in the creation of small bubbles in the soap. This, along with its ability to suspend dirt in mixtures, can make soaps and other cleaning products more efficient.[20]

Textile uses

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CMC is used in textiles as a thickening agent in textile printing, constituting about 2-3% of printing pastes. It is also used in fabric finishing to affect the fabric's texture. Additionally, CMC serves as a binding agent in non-woven fabrics, contributing to the strength and stability of the material. In sizing applications, about 1-3% of CMC is used to protect yarns during weaving to reduce breakages.

CMC aids in thickening printing pastes, which makes the prints themself more precise. It is also used to thicken dyes. Additionally, it is an alternative to synthetic thickeners.[21]

Cosmetics uses

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CMC is an ingredient used in over 50% of cosmetic products. As a thickening agent, it is used in formulations where viscosity needs to be precisely controlled. In hair care, about 25% of shampoos and conditioners utilize CMC for its conditioning and detangling effects. It is also used in the makeup and toothpaste industries to control the products' texture. Due to its ability to retain moisture, it is also used in skincare products. CMC serves as a film-forming agent in approximately 10% of sunscreens.

CMC aids in pigment suspension and dispersion, binding other ingredients for even distribution. CMC, when combined with Fatty Acid Ethanolamine or 2,2'-Iminodiethanol in a hair product, can form a thin film around the hair.[22]

Specific culinary uses

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CMC powder is widely used in the ice cream industry, to make ice creams without churning or extremely low temperatures, thereby eliminating the need for conventional churners or salt ice mixes.[23] CMC is used in baking breads and cakes. The use of CMC gives the loaf an improved quality at a reduced cost, by reducing the need for fat. CMC is also used as an emulsifier in biscuits. Dispersing fat uniformly in the dough, improves the release of the dough from the molds and cutters, achieving well-shaped biscuits without any distorted edges. It can also help to reduce the amount of egg yolk or fat used in making the biscuits. The use of CMC in candy preparation ensures smooth dispersion in flavor oils and improves texture and quality. CMC is used in chewing gums, margarine, and peanut butter as an emulsifier.[24]

Medical applications

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CMC is also used in numerous medical applications.[25][26][27][28]

Some examples include:

  1. Device for epistaxis (nose bleeding). A poly-vinyl chloride (PVC) balloon is covered by CMC knitted fabric reinforced by nylon. The device is soaked in water to form a gel, which is inserted into the nose of the balloon and inflated. The combination of the inflated balloon and the therapeutic effect of the CMC stops the bleeding.[29]
  2. Fabric used as a dressing following ear nose and throat surgical procedures.[30]
  3. Water is added to form a gel, and this gel is inserted into the sinus cavity following surgery.[31]

In ophthalmology, CMC is used as a lubricating agent in artificial tears solutions for the treatment of dry eyes.[32]

In veterinary medicine, CMC is used in abdominal surgeries in large animals, particularly horses, to prevent the formation of bowel adhesions.[33]

Research applications

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Insoluble CMC (water-insoluble) can be used in the purification of proteins, particularly in the form of charged filtration membranes or as granules in cation-exchange resins for ion-exchange chromatography.[34] Its low solubility is a result of a lower DS value (the number of carboxymethyl groups per anhydroglucose unit in the cellulose chain) compared to soluble CMC.[35] Insoluble CMC offers physical properties similar to insoluble cellulose, while the negatively charged carboxylate groups allow it to bind to positively charged proteins.[36] Insoluble CMC can also be chemically cross-linked to enhance the mechanical strength of the material.[37]

Moreover, CMC has been used extensively to characterize enzyme activity from endoglucanases (part of the cellulase complex); it is a highly specific substrate for endo-acting cellulases, as its structure has been engineered to decrystallize cellulose and create amorphous sites that are ideal for endoglucanase action.[citation needed] CMC is desirable because the catalysis product (glucose) is easily measured using a reducing sugar assay, such as 3,5-dinitrosalicylic acid.[citation needed] Using CMC in enzyme assays is especially important in screening for cellulase enzymes that are needed for more efficient cellulosic ethanol conversion.[citation needed] CMC was misused in early work with cellulase enzymes, as many had associated whole cellulase activity with CMC hydrolysis.[according to whom?] As the mechanism of cellulose depolymerization became better understood, it became clear that exo-cellulases are dominant in the degradation of crystalline (e.g. Avicel) and not soluble (e.g. CMC) cellulose.[citation needed]

Other uses

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In laundry detergents, it is used as a soil suspension polymer designed to deposit onto cotton and other cellulosic fabrics, creating a negatively charged barrier to soils in the wash solution.[citation needed] CMC is also used as a thickening agent, for example, in the oil-drilling industry as an ingredient of drilling mud, where it acts as a viscosity modifier and water retention agent.[citation needed]

CMC is sometimes used as an electrode binder in advanced battery applications (i.e. lithium ion batteries), especially with graphite anodes.[38] CMC's water solubility allows for less toxic and costly processing than with non-water-soluble binders, like the traditional polyvinylidene fluoride (PVDF), which requires toxic n-methylpyrrolidone (NMP) for processing.[citation needed] CMC is often used in conjunction with styrene-butadiene rubber (SBR) for electrodes requiring extra flexibility, e.g. for use with silicon-containing anodes.[39]

CMC is also used in ice packs to form a eutectic mixture resulting in a lower freezing point, and therefore more cooling capacity than ice.[40]

Aqueous solutions of CMC have also been used to disperse carbon nanotubes, where the long CMC molecules are thought to wrap around the nanotubes, allowing them to be dispersed in water.[citation needed]

In conservation-restoration, it is used as an adhesive or fixative (commercial name Walocel, Klucel).[citation needed]

Adverse reactions

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Effects on inflammation, microbiota-related metabolic syndrome, and colitis are a subject of research.[41] Carboxymethyl cellulose is suggested as a possible cause of inflammation of the gut [[2]], through alteration of the human gastrointestinal microbiota, and has been suggested as a triggering factor in inflammatory bowel diseases such as ulcerative colitis and Crohn's disease.[42][non-primary source needed]

While thought to be uncommon, case reports of severe reactions to CMC exist.[43] Skin testing is believed to be a useful diagnostic tool for this purpose.[44] CMC was the active ingredient in an eye drop brand Ezricare Artificial Tears which was recalled due to potential bacterial contamination.[45]

See also

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References

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Which is better, CMC or HPMC? - LinkedIn

Comparing CMC (carboxymethylcellulose) and HPMC (hydroxypropylmethylcellulose) is not necessarily a question of one being "better" than the other. Both are widely used in a variety of industries and applications, and each technology has its own advantages and disadvantages depending on the specific requirements of the application.

 

Carboxymethylcellulose (CMC):

 

1. Performance:

CMC is a water-soluble polymer derived from cellulose.

It usually comes in powder form.

It is stable over a wide pH range.

Forms a viscous solution when dissolved in water.

 

2. Application:

CMC is widely used in the food industry as a thickener, stabilizer and binder in products such as ice cream, sauces and baked goods.

It is also used in pharmaceuticals as a binder in tablet formulations and in personal care products such as toothpaste and cosmetics.

In the textile industry, CMC is used as a sizing agent and in the production of synthetic fibers.

 

3. Advantages:

Excellent water retention properties, making it suitable for applications requiring humidity control.

Effective thickener and stabilizer.

Non-toxic and safe for use in food and medicine.

Cost effective compared to some other thickeners.

 

4. Disadvantages:

Limited thermal stability, which may limit its use in high temperature applications.

May not be suitable for applications requiring high definition or transparency.

 

Hydroxypropyl methylcellulose (HPMC):

 

1. Performance:

HPMC is a semi-synthetic polymer derived by introducing hydroxypropyl and methyl groups.

It is available in various viscosity grades.

Like CMC, it is water-soluble and forms a clear solution.

HPMC can exhibit thermogelling behavior, meaning that it forms a gel when heated and returns to a solution when cooled.

 

2. Application:

HPMC is commonly used as a thickener, binder, film-forming agent, and emulsifier in pharmaceuticals, especially in controlled-release formulations.

It is used in building materials such as cement products to improve workability and water retention.

In the food industry, HPMC is used as a thickener and stabilizer in products such as baked goods, beverages and dairy products.

It is also used in personal care products such as lotions, creams and shampoos to improve texture and stability.

 

3. Advantages:

Versatile and can be used in a variety of applications including pharmaceutical, food, construction and personal care.

Better thermal stability compared to CMC, making it suitable for applications involving heat treatment.

Provides excellent film-forming properties, which is advantageous in coatings and pharmaceutical tablet formulations.

Provides a high degree of transparency in aqueous solutions, making it suitable for products requiring transparency.

 

4. Disadvantages:

Typically more expensive than CMC, which may affect its cost-effectiveness in some applications.

Although generally considered safe, it may cause allergic reactions in sensitive individuals.

 

Compare:

 

1. Application scope:

CMC and HPMC have overlapping applications in industries such as food, pharmaceuticals and personal care. However, HPMC has a wider range of applications due to its superior thermal stability and transparency.

 

2. Performance:

In terms of thickening and stabilizing properties, both CMC and HPMC are effective. However, HPMC can provide better performance in applications requiring thermal stability and transparency.

 

3. Cost:

CMC is generally more cost-effective than HPMC. However, the choice between the two may also depend on the specific requirements of the application and the desired performance characteristics.

 

4.Safety:

Both CMC and HPMC are considered safe for consumption and use in a variety of applications. However, people with allergies or sensitivities should use caution, especially HPMC.

 

5. Environmental considerations:

Both CMC and HPMC are derived from cellulose, a renewable resource. However, the manufacturing process and any associated environmental impacts may differ between the two.

 

Whether CMC or HPMC is "better" depends on the specific requirements of the application. CMC may be favored for its cost-effectiveness and water retention properties, while HPMC may be favored for its superior thermal stability, transparency, and broader applications. Ultimately, the selection should be based on factors such as performance requirements, cost considerations, and environmental impact.

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