Cellulose Ether Classification
Cellulose ether is a general term for a series of products produced by the reaction of alkali cellulose and etherifying agent under certain conditions. When alkali cellulose is replaced by different etherifying agents, different cellulose ethers will be obtained.
According to the ionization properties of substituents, cellulose ethers can be divided into two categories: ionic (such as carboxymethyl cellulose) and nonionic (such as methyl cellulose).
According to the type of substituent, cellulose ether can be divided into monoether (such as methyl cellulose) and mixed ether (such as hydroxypropyl methyl cellulose).
According to different solubility, it can be divided into water solubility (such as hydroxyethyl cellulose) and organic solvent solubility (such as ethyl cellulose).
Water-soluble cellulose ethers used in dry-mixed mortars are divided into instant-dissolving and surface-treated delayed-dissolving cellulose ethers.
Where are their differences? And how to smoothly configure it into a 2% aqueous solution for viscosity testing?
What is surface treatment?
Effect on cellulose ether?
first
Surface treatment is a method of artificially forming a surface layer on the surface of a base material with mechanical, physical and chemical properties different from that of the base.
The purpose of surface treatment of cellulose ether is to delay the time of combining cellulose ether with water to meet the slow thickening requirements of some paint mortars, and also to increase the corrosion resistance of cellulose ether and improve storage stability.
The difference when cold water is configured with 2% aqueous solution:
The surface-treated cellulose ether can quickly disperse in cold water and is not easy to agglomerate due to its slow viscosities;
Cellulose ether without surface treatment, due to its fast viscosities, will viscous before it is completely dispersed in cold water, and is prone to agglomeration.
How to configure the non-surface-treated cellulose ether?
1. First put in a certain amount of non-surface-treated cellulose ether;
2. Then add hot water at about 80 degrees Celsius, the weight is one-third of the required water volume, so that it can fully swell and disperse;
3. Next, slowly pour in cold water, the weight is two-thirds of the remaining water required, keep stirring to make it sticky slowly, and there will be no agglomeration;
4. Finally, under the condition of equal weight, put it into a constant temperature water bath until the temperature drops to 20 degrees Celsius, and then the viscosity test can be carried out!
Post time: Feb-02-2023