Why MHEC is being preferred over HPMC for Cellulose Ether

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Cellulose Ether is derived from Cellulose and is a water-soluble compound used in several industries. It finds its usage mainly in the construction, food, pharmaceutical, and cosmetics industries. Specifically, Cellulose Ether is primarily used in the construction sector as it acts as a binder, thickener, and water retention agent in construction. There are different grades of Cellulose Ether, which have their applicability and properties. The two primary grades of Cellulose Ether HPMC (Hydroxypropyl Methyl Cellulose) and MHEC (Methyl Hydroxyethyl Cellulose) have varied similarities, yet one is more preferred than the other in recent days.

Nowadays, MHEC grade of Cellulose Ether is more preferred than the HPMC grade in the construction industry. Though, both are being utilized widely for increasing bond strength and water retention capacity of a dry mixture of cement and gypsum, few properties differentiate them. The first property differentiating MHEC from HPMC is gel temperature; the gel temperature of MHEC is higher than that of MHEC. The gel temperature of HPMC is around 60°c - 70°c, which varies as per its content and production technique; however, the gel temperature of MHEC is generally more than 80°C, which makes it a better alternative. MHEC has better thermal stability owing to its high gel temperature, causing better water retention capacity during summers in South Asian Countries.

Furthermore, MHEC has a more significant number of Hydrophilic groups in its structure, eventually leading to more hydrophilicity than the HPMC grade. Having more Hydrophilic groups makes MHEC better in water retention, and hence it is preferred more. In addition, the prices of MHEC grades have been lesser than that of HPMC, making them more economical to use. In India, the prices of Cellulose Ether, with respective to all grades, have been marginally increasing from the first week of April.

According to ChemAnalyst, &#;MHEC grade would be chosen over HPMC grade in countries including India as summers have already approached. Construction industries would go for having cellulose ether with higher gel temperature and better hydrophilicity. Furthermore, the Indian domestic market of Cellulose Ether is most likely to showcase stagnant to a marginal rise in the prices.&#;

Hydroxypropyl Methyl Cellulose (HPMC)

In recent years, the production and usage of Hydroxypropyl Methyl Cellulose (HPMC) have been increasing rapidly. Hydroxypropyl methyl cellulose is a non-ionic cellulose mixed ether made from refined cotton by alkalization treatment, using propylene oxide and chloromethane as etherizers, through various chemical reactions. The substitution degree of hydroxypropyl methylcellulose is generally 1.2~2.0, and its properties are different by the ratio of methoxy content and hydroxypropyl content. Specifically, you can learn about the &#;Effect of methoxy content and hydroxypropoxy content on HPMC&#;.

1. Hydroxypropyl methyl cellulose is easily soluble in cold water, and will encounter difficulties when dissolved in hot water. Its gelation temperature in hot water is significantly higher than that of methyl cellulose. The dissolution in cold water is also greatly improved compared to methyl cellulose.
2. The viscosity of hydroxypropyl methyl cellulose is related to its molecular weight, large molecular weight is high viscosity. Temperature also affects its viscosity, and the viscosity decreases when the temperature rises. However, its viscosity is less affected by temperature than that of methyl cellulose. Its solution is stable when stored at room temperature.
3. The water retention of hydroxypropyl methyl cellulose depends on its additive amount, viscosity, etc., and the water retention rate is higher than that of methyl cellulose under the same additive amount.
4. Hydroxypropyl methyl cellulose is stable to acid and alkali, and its aqueous solution is very stable in the range of pH=2~12. Caustic soda and lime water do not have much effect on its performance, but alkali can accelerate its dissolution rate. Hydroxypropyl methyl cellulose has stability to general salts, but when the concentration of salt solution is high, the viscosity of hydroxypropyl methyl cellulose solution will have a tendency to increase.
5. Hydroxypropyl methyl cellulose can be mixed with water-soluble polymer compounds to become uniform, higher viscosity solution. Such as polyvinyl alcohol, vegetable gum, etc.
6. Hydroxypropyl methyl cellulose has better enzyme resistance than methyl cellulose, and the possibility of enzymatic degradation of its solution is lower than that of methyl cellulose. Hydroxypropyl methyl cellulose adhesion to mortar construction is higher than methyl cellulose.

If you want to learn more, please visit our website hydroxyethyl methyl cellulose.

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Methyl cellulose (MC)

Methyl cellulose is refined cotton treated with alkali and then made into cellulose ether through a series of reactions using methylene chloride as the etherifying agent. The general degree of substitution is 1.6~2.0, and the solubility varies with the degree of substitution. It belongs to non-ionic cellulose ether.

1. Methyl cellulose is soluble in cold water, hot water solubility will encounter difficulties, and its aqueous solution is very stable in the range of pH=3~12. It is compatible with starch, guanidinium gum, etc. and many surfactants. When the temperature reaches the gelation temperature, gelation will occur.
2. The water retention of methyl cellulose depends on its addition amount, viscosity, particle fineness and dissolution speed. Generally the larger the addition amount, the smaller the fineness and the larger the viscosity, the higher the water retention rate. The viscosity is not directly proportional to the water retention rate. The dissolution rate mainly depends on the degree of surface modification of cellulose particles and particle fineness. Among the several cellulose ethers introduced in this paper, methyl cellulose and hydroxypropyl methyl cellulose have higher water retention rates.
3. Changes in temperature can seriously affect the water retention of methyl cellulose. Generally the higher the temperature, the worse the water retention. If the mortar temperature exceeds 40 &#;, the water retention of methyl cellulose will be significantly worse, seriously affecting the constructability of mortar.
4. Methyl cellulose has a significant impact on the construction and adhesion of mortar. The &#;adhesion&#; refers to the adhesion between the applicator and the wall substrate, i.e. the shear resistance of the mortar. Adhesion is large, the shear resistance of the mortar is large, the force required by the workers in the process of application is also large, and the constructability of the mortar is poor. In the cellulose ether products methyl cellulose adhesion is at a medium level.

Hydroxyethyl cellulose (HEC)

Hydroxyethyl cellulose is made from refined cotton treated with alkali and reacted in the presence of acetone with ethylene oxide as the etherifying agent. Its substitution degree is generally 1.5~2.0. It has strong hydrophilicity and is easy to absorb moisture.

1. Hydroxyethyl cellulose can be dissolved in cold water, hot water is more difficult to dissolve. Its solution is stable at high temperature and does not have gelation. It can be used for a longer time in mortar under high temperatures, but the water retention is lower than methyl cellulose.
2. hydroxyethyl cellulose has the stability to general acid and alkali, alkali can accelerate its dissolution, and can slightly increase viscosity, its dispersion in water than methyl cellulose and hydroxypropyl methyl cellulose is slightly worse.
3. Hydroxyethyl cellulose has good performance on mortar anti-hanging, but the retardation time of cement is longer.
4. The performance of hydroxyethyl cellulose produced by some Chinese enterprises is significantly lower than that of methyl cellulose due to high water content and high ash content.

Carboxymethyl cellulose (CMC)

Carboxymethyl cellulose is made from natural fiber (cotton, etc.) after alkali treatment, with sodium monochloroacetate as the etherifying agent, after a series of reaction processing and made of ionic cellulose ether. Its substitution degree is generally 0.4~1.4, and the performance is greatly affected by the substitution degree.

1. Carboxymethyl cellulose is more hygroscopic and will contain more water when stored in general conditions.
2. Carboxymethyl cellulose aqueous solution will not produce gel, with the increase in temperature and viscosity decline, the temperature exceeds 50 &#;, the viscosity will be irreversible.
3. The stability of carboxymethyl cellulose is greatly affected by pH. Generally it can be used in gypsum-based mortar, not in cement-based mortar. At high alkalinity, it will lose viscosity.
4. The water retention of carboxymethyl cellulose is much lower than methyl cellulose. It has retardation effect on gypsum-based mortar and reduces its strength. However, the price of carboxymethyl cellulose is significantly lower than methyl cellulose.

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