Cellulose ether is a synthetic polymer made from natural cellulose through chemical modification. Cellulose ether is a derivative of natural cellulose. The production of cellulose ether is different from synthetic polymers. Its most basic material is cellulose, a natural polymer compound. Due to the particularity of the natural cellulose structure, the cellulose itself has no ability to react with etherification agents. However, after the treatment of the swelling agent, the strong hydrogen bonds between the molecular chains and the chains are destroyed, and the active release of the hydroxyl group becomes a reactive alkali cellulose. Obtain cellulose ether.
The properties of cellulose ethers depend on the type, number and distribution of substituents. The classification of cellulose ether is also classified according to the type of substituent, degree of etherification, solubility and related application properties. According to the type of substituents on the molecular chain, it can be divided into monoether and mixed ether. The MC we usually use is monoether, and the HPMC is mixed ether. Methyl cellulose ether MC is the product after the hydroxyl group on the glucose unit of natural cellulose is substituted by methoxy. It is a product obtained by substituting a part of the hydroxyl group on the unit with a methoxy group and another part with a hydroxypropyl group. The structural formula is [C6H7O2(OH)3-m-n(OCH3)m[OCH2CH(OH)CH3]n]x Hydroxyethyl methyl cellulose ether HEMC, these are the main varieties widely used and sold in the market.
In terms of solubility, it can be divided into ionic and non-ionic. Water-soluble non-ionic cellulose ethers are mainly composed of two series of alkyl ethers and hydroxyalkyl ethers. Ionic CMC is mainly used in synthetic detergents, textile printing and dyeing, food and oil exploration. Non-ionic MC, HPMC, HEMC, etc. are mainly used in construction materials, latex coatings, medicine, daily chemicals, etc. Used as thickener, water retaining agent, stabilizer, dispersant and film forming agent.
Quality identification of cellulose ether:
Effect of methoxyl content on quality: water retention and thickening function
Quality influence of hydroxyethoxyl/hydroxypropoxyl content: the higher the content, the better the water retention.
Influence of viscosity quality: the higher the degree of polymerization, the higher the viscosity and the better the water retention.
The influence of fineness quality: the finer the dispersion and dissolution in the mortar, the faster and more uniform it is, and the relative water retention is better
Quality impact of light transmittance: the higher the degree of polymerization, the more uniform the degree of polymerization, and the less impurities
Gel temperature quality impact: the gel temperature for construction is around 75°C
Influence of water quality: <5%, cellulose ether is easy to absorb moisture, so it should be sealed and stored
Ash quality impact: <3%, the higher the ash, the more impurities
PH value quality impact: close to neutral, cellulose ether has stable performance between PH: 2-11
Post time: Feb-14-2023