HPMC VS HEC: How to make a choice?

In recent years the cellulose industry has developed rapidly, there are industrial monosodium glutamate carboxymethyl cellulose, hydroxypropyl methyl cellulose, and hydroxyethyl cellulose these three kinds of cellulose have the largest amount. These three kinds of cellulose in the most difficult to distinguish between hydroxypropyl methyl cellulose and hydroxyethyl cellulose, In the following we will distinguish between these two kinds of cellulose through the use and role.

HPMC, HEC Introduction

HEC has the properties of thickening, suspending, bonding, emulsifying, dispersing, retaining moisture, and protecting colloids. It can be used to prepare solutions of different viscosity ranges. It is unstable under normal temperature and pressure, avoiding moisture, heat, and high temperature, it has exceptionally good salt solubility for dielectrics, and its aqueous solution is allowed to contain a high concentration of salts while being stable.
HPMC has thickening ability, salt resistance low ash powder, PH stability, water retention, dimensional stability, excellent film-forming properties, as well as a wide range of enzyme resistance, dispersion, and adhesion characteristics.

Differences between HPMC and HEC

Appearance

Hydroxypropyl Methyl Cellulose: (HPMC) is a white or similar white fibre or granular powder
Hydroxyethyl cellulose: (HEC) is a white or yellow, odorless, and non-toxic fibre or powder solid.

Chemical Properties

HPMC is a non-ionic cellulose mixed ether and is a semi-synthetic inactive viscoelastic polymer.
HEC is etherified from basic cellulose and ethylene oxide (or chloroethanol). It is a non-ionic soluble cellulose ether.

Differences in solubility

Hydroxypropyl methylcellulose: Almost insoluble in anhydrous ethanol, ether, and acetone. Soluble in clear or slightly turbid colloidal solution in cold water.
Hydroxyethyl cellulose: It has the properties of thickening, suspending, bonding, emulsifying, dispersing, and moisturizing. It can prepare solutions of different viscosity ranges and has excellent salt solubility for electrolytes.

Different PH range

HEC has a wider pH range than HPMC.
HEC PH value in the range of 2-12 viscosity change is small, but beyond this range, viscosity decreases.
The PH of HPMC is in the range of 5.0-8.5.

Dispersibility

HEC has twice the water retention capacity of methylcellulose and offers better flow regulation;

Water Retention

HEC has the least dispersive ability compared to the recognized methyl cellulose and hydroxypropyl methyl cellulose, but the greatest ability to protect colloids.

Properties

Hydroxypropylmethylcellulose (HPMC) decreases with decreasing methoxyl content, increasing gel point, decreasing water solubility, and decreasing surface activity.HEC has more stable properties.

Application of HPMC and HEC

Hydroxypropyl methylcellulose is mostly used as a thickener, dispersant, and stabilizer in the coating industry, with good solubility in water or organic solvents. In the construction industry, it is used in cement, gypsum, latex putty, mortar, etc. It can improve the dispersibility of cement sand and greatly improve the plasticity and water retention of mortar.
HEC is used as an adhesive, surfactant, colloid protector, dispersant, emulsifier, and dispersion stabilizer. It has a wide range of applications in the fields of paint, ink, fiber, dyeing, papermaking, cosmetics, pesticides, mineral processing, oil extraction, and medicine.

When choosing between HEC and HPMC, several factors need to be taken into consideration:

  1. Consider the viscosity and solubility requirements of your application. If you require a thick, viscous consistency, HEC might be the better choice. If you need a thinner, more fluid consistency, HPMC may be more suitable.
  2. Take into account the pH range and film-forming characteristics required for your application. If you need stability or excellent film-forming performance over a broader pH range, HEC might be the preferable option. If stability under acidic conditions is needed, or if you can tolerate poorer film-forming performance, HPMC may be more suitable.

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