Cellulose ether example is a polymer compound made of cellulose with an ether structure. Each glucose ring in the cellulose macromolecule contains three hydroxyl groups, the primary hydroxyl group on the sixth carbon atom, and the secondary hydroxyl group on the second and third carbon atoms. The hydrogen in the hydroxyl group is replaced by the hydrocarbon group to form cellulose. It is the product of the substitution of hydroxyl hydrogen by hydrocarbon group in cellulose polymer. Cellulose is a polyhydroxy polymer compound that neither dissolves nor melts. Cellulose can be dissolved in water, dilute alkali solution and organic solvent after etherification, and has thermoplastic properties.
Cellulose ether is the general term of a series of products generated by the reaction of alkali cellulose and etherifying agent under certain conditions. Alkali cellulose is substituted by different etherifying agents to obtain different cellulose ethers.
According to the ionization properties of substituents, cellulose ethers example can be divided into ionic (such as carboxymethyl cellulose) and non-ionic (such as methyl cellulose) two categories.
According to the type of substituent, cellulose ethers example can be divided into single ether (such as methyl cellulose) and mixed ether (such as hydroxypropyl methyl cellulose). According to solubility, can be divided into water soluble (such as hydroxyethyl cellulose) and organic solvent solubility (such as ethyl cellulose). Dry mixed mortar mainly uses water-soluble cellulose, which can be divided into quick-dissolving type and delayed dissolving type after surface treatment.
Admixtures play a key role in improving the properties of dry-mixed mortar and account for more than 40% of the material cost in dry-mixed mortar. A considerable part of the admixture in the domestic market is supplied by foreign manufacturers, and the reference dosage of the product is also provided by suppliers. As a result, the cost of dry-mixed mortar products remains high, and it is difficult to popularize common masonry mortar and plastering mortar with large quantity and wide area. High-end market products are controlled by foreign companies, dry mortar manufacturers low profits, poor price affordability; The application of admixture lacks systematic and targeted research, blindly follow foreign formulations.
Water retention agent is the key admixture to improve the water retention performance of dry mixed mortar and also one of the key admixtures to determine the material cost of dry mixed mortar. The main function of cellulose ether is to retain water.
The action mechanism of cellulose ether in mortar is as follows:
(1) mortar in cellulose ether dissolved in water, because the surface active role to ensure the gelled material effectively uniform distribution in the system, and cellulose ether as a kind of protective colloid, “package” solid particles, and on its exterior surface to form a layer of lubrication film, the slurry system more stable, and also improves the slurry in the mixing process of liquidity and the construction of the slip may just as well.
(2) Cellulose ether solution due to its own molecular structure characteristics, so that the water in mortar is not easy to lose, and gradually released in a longer period of time, giving mortar good water retention and workability.
Post time: Dec-14-2021