What is Cellulose Ether?

Cellulose ether is the powdered cellulose ether generated with wood fiber or refined short cotton fiber as the main raw materials, after chemical treatment and by the reaction of etherifying agents such as chlorinated ethylene, chlorinated propylene and oxidized ethylene.

The production process of cellulose ether is complex. It starts with the extraction of cellulose from cotton or wood, which then transforms into alkaline cellulose after adding sodium hydroxide and by chemical reaction (alkaline solution). Under the action of etherifying agents (etherification reaction), cellulose ethers are generated from alkaline cellulose through such processes as washing with water, drying and grinding.

Different etherifying agents can turn alkaline cellulose into different types of cellulose ethers. The molecular structure of cellulose is composed of the molecular bonds of dehydrated glucose units. Each glucose unite contains three hydroxyl groups. Under certain conditions, the hydroxyl groups will be substituted by methyl, hydroxyethyl, hydroxypropyl and the like groups, and can form cellulose of different varieties (for example, if substituted by methyl, then it is called methyl cellulose; if substituted by hydroxyethyl, then it is called hydroxyethyl cellulose; if substituted by hydroxypropyl, then it is called hydroxypropyl cellulose). Since methyl cellulose is a mixed ether produced by the etherification reaction, with methyl as the main material but containing a small amount of hydroxyethyl or hydroxypropyl, it is called methyl hydroxyethyl cellulose ether or methyl hydroxypropyl cellulose ether. 

Due to the difference in the substituents (such as methyl, hydroxyethyl and hydroxypropyl) and the difference in the degree of substitution (the amount of substituted substance of reactive hydroxyl in each cellulose), cellulose ethers of different varieties and grades can be obtained. Different varieties can be widely used in construction, food and pharmaceutical industries, as well as other different fields such as daily chemical industry and petroleum industry.

Cellulose ethers used in the building materials are mainly methyl cellulose ether (MC), hydroxypropyl methyl cellulose ether (HPMC), hydroxyethyl methyl cellulose ether (HEMC), hydroxyethyl cellulose ether (HEC), hydroxyethyl ethy cellulose ether (EHEC), etc. Among them, HPMC and HEMC have been widely used in dry mixed mortar products due to their excellent characteristics.