The key difference between carboxymethyl cellulose and hydroxypropyl methylcellulose is that carboxymethyl cellulose has a lower water retention rate, whereas hydroxypropyl methylcellulose has a higher water retention rate when compared in the same amounts.
Water retention rate is the measure of how much water can be retained in a material. Carboxymethyl cellulose and hydroxypropyl methylcellulose are derivatives of cellulose having differences in water retention rates.
CONTENTS
1. Overview and Key Difference
2. What is Carboxymethyl Cellulose
3. What is Hydroxypropyl Methylcellulose
4. Carboxymethyl Cellulose vs Hydroxypropyl Methylcellulose in Tabular Form
5. Summary – Carboxymethyl Cellulose vs Hydroxypropyl Methylcellulose
What is Carboxymethyl Cellulose?
Carboxymethyl cellulose is a derivative of cellulose having the carboxymethyl groups, which are bonded to the hydroxyl groups of the glucopyranose monomers. Glycopyranose monomers are the units that make up the backbone of the cellulose structure. Often, this material is useful in its sodium salt form. It is known as sodium carboxymethyl cellulose. We can find this substance marketed under the name Tylose.
Figure 01: Repeating Unit of Carboxymethyl Cellulose
When considering the production of carboxymethyl cellulose, we can synthesize it through the alkali catalyzed reaction of cellulose in the presence of chloroacetic acid. In this production procedure, the polar carboxyl groups render the cellulose soluble and also reactive chemically. This initial step gives a reaction mixture consisting of about 60% of carboxymethyl cellulose and about 40% of salts such as sodium chloride and sodium glycolate. Technically, this product is an ingredient in detergents. However, we can use a further purification method to remove the salt components and get pure carboxymethyl cellulose which is useful in industries such as food, pharmaceutical, and toothpaste production. Moreover, this process gives an intermediate product that comes under “semipurified grade” and is useful in paper production applications.
There are many different uses of carboxymethyl cellulose, and a few of them include use in the food industry under the E number E466 as a viscosity modifier or thickener and is helpful in stabilizing emulsions in various products such as ice cream. Moreover, this substance is included in many non-edible products, including toothpaste, laxatives, diet pills, water-based paints, detergents, textile sizing, paper products, etc.
What is Hydroxypropyl Methylcellulose?
Hydroxypropyl methylcellulose is a medication useful in treating dry eyes and treating eye irradiation. The common side effects of this medication include signs of allergic reactions such as rash, hives, itching, red and swollen and peeling skin, tightness in the chest or throat, change in eyesight, eye pain, and bad eye irritation. This medication can be stored at room temperature, out of reach of children.
Figure 02: Repeating Unit of Hypromellose
Hydroxypropyl methylcellulose is also known as hypromellose, and it is a semisynthetic, inert, viscoelastic polymer. In addition to its use in pharmaceutical products, this substance is also useful in the food industry as a food additive, where it can act as an emulsifier, thickening and suspending agent, and also as an alternative to animal gelatin. The E number for this material in the food industry is E 464.
Usually, this substance is produced in solid form, which has a slightly off white appearance, and it can also be formed into granules. These granules can form colloids when added to water. It is a nontoxic ingredient that is combustible, and it can also react vigorously with oxidizing agents.
Among many uses of Hypromellose, the most common applications include using it as tile adhesives, cement renders, gypsum products, pharmaceutical, paints and coatings, food, cosmetics, detergents and cleaners, eye drops, etc.
What is the Difference Between Carboxymethyl Cellulose and Hydroxypropyl Methylcellulose?
Water retention rate is the measure of how much water can be retained in a material. The key difference between carboxymethyl cellulose and hydroxypropyl methylcellulose is that carboxymethyl cellulose has a lower water retention rate, whereas hydroxypropyl methylcellulose has a higher water retention rate when compared in same amounts.
The following infographic presents the difference between carboxymethyl cellulose and hydroxypropyl methylcellulose in tabular form.
Summary – Carboxymethyl Cellulose vs Hydroxypropyl Methylcellulose
Carboxymethyl cellulose and hydroxypropyl methylcellulose are derivatives of cellulose having differences in water retention rates. The key difference between carboxymethyl cellulose and hydroxypropyl methylcellulose is that carboxymethyl cellulose has a lower water retention rate, whereas hydroxypropyl methylcellulose has a higher water retention rate when compared in same amounts.
Reference:
1. “Hydroxypropyl Methylcellulose.” National Center for Biotechnology Information. PubChem Compound Database, U.S. National Library of Medicine.
Image Courtesy:
1. “Carboxymethyl cellulose” By Edgar181 – Own work (Public Domain) via Commons Wikimedia
2. “Hypromellose” By Edgar181 – Own work (Public Domain) via Commons Wikimedia
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