HPMC and HEC, both of them are a kind of cellulose ether. but what is the difference between them? HPMC VS HEC. In recent years, the output and consumption of HPMC have been increasing rapidly. HPMC is an ironic cellulose ether. it begins refined cotton after alkalization treatment. Propylene oxide and methyl chloride is the etherifying agent in the HPMC manufacturing process. After a series of reactions, get HPMC. But HEC also begins refined cotton after alkalization treatment. With acetone, HEC uses ethylene oxide as the etherifying agent. So HEC has more hydrophilic than HPMC. It is prone to absorb moisture.
This article focuses on HPMC and HEC degree of substitution (DS), appearance, solution, dispersion, ph, and application.
1. HPMC VS HEC: DS
DS: the substituent of HPMC is Hydroxypropyl and Methoxy. The ratio of them affects HPMC properties. The higher the hydroxypropyl content, the better the water retention effect. The lower the methoxy content, the higher the gel temperature. The DS of HPMC is 1.2-2.0. But HEC substituent is Hydroxyethyl substituent. Its DS is 1.5-2.0.
2. HPMC VS HEC : Appearance
Appearance: both HPMC and HEC are white powder. HPMC is a Non-ionic compound, a non-reactive viscoelastic polymer. HEC raw material is Alkaline Cellulose and Ethylene Oxide.
3.HPMC VS HEC : Solubility
Solubility: HPMC is practically insoluble in absolute ethanol, ether, and acetone. HPMC is soluble in cold water and insoluble in hot water. HPMC will get gel when the temperature is up to 55-75. Hydroxypropyl methylcellulose after gelation is like jelly. This gel is related to methoxy content.
HEC is soluble in hot and cold water. No precipitation at high temperatures or boiling. Wide range of solubility and viscosity characteristics and non-thermogelling properties. HEC can produce solutions with different viscosity. It has good salt-dissolving properties for electrolytes.
4. HPMC VS HEC : Dispersion
Dispersion: the dispersion of HPMC is better than HEC. But HEC has a stronger protective colloid than HPMC.
5. HPMC VS HEC : PH
PH: both HPMC and HEC are stable to common acids and alkalis. Alkali can speed up its dissolution and slightly increase its viscosity. HPMC solution is stable in the range of ph = 2-12. caustic soda and lime water can not affect HPMC properties. Hydroxypropyl methylcellulose is stable to common salts. But when the concentration of salt solution is high, the viscosity of HPMC solution tends to increase.
6. HPMC VS HEC : Application
Application: Hydroxypropyl methylcellulose can be used in coatings, ceramics, printing inks, plastics. HPMC has construction grade, food grade, and pharmaceutical grade according to the application. The construction industry is the most widely used application for MELACOLL hydroxypropyl methylcellulose.
Low-viscosity hydroxypropyl methylcellulose is mainly used for self-leveling mortar. Its viscosity is low, although its water retention is poor. HPMC 's leveling property is good, and the mortar is dense. Medium and low-viscosity HPMC is mainly used in tile adhesives, joint fillers, anti-cracking mortars, and thermal insulation mortars. It has good constructability, a good water retention effect, and high mortar density. HPMC exists as a water-retaining agent in mortar. Its water-retaining properties prevent the paste from drying too quickly. And cracking after reapplying.
HEC is the binder, surfactant, colloidal protective agent, dispersant, emulsifier, dispersion stabilizer. Hydroxyethyl cellulose mainly apply to the coating industry. Hydroxyethylcellulose is more stable than hydroxypropylmethylcellulose for emulsion thickening.