Cellulose ether is the main admixture in dry-mix mortar products and plays a significant role in their performance and cost.
Most of this product is used in building materials. Today, we will talk about: what characteristics can affect the performance of the mortar? And what factors can affect it?
01
Fineness of cellulose ether
The fineness of the cellulose ether affects its solubility. The finer the cellulose ether, the faster it dissolves in water and the better its water retention properties. Therefore, the fineness of the cellulose ether should be one of the properties considered.
Generally speaking, a fineness of 80 mesh is sufficient for the cellulose ether.
02
Cellulose ether dry weight loss rate
The drying weight loss rate refers to the percentage of the mass of the material lost during the drying of the cellulose ether at a certain temperature compared to the original sample mass.
A high drying weight loss rate in a certain mass of cellulose ether will reduce the content of the active ingredients in the cellulose ether, affect the effect of downstream enterprises’ applications, and also increase the purchase cost.
Normally, the drying weight loss rate of cellulose ether is not greater than 5.0%.
03
Sulfate ash content of cellulose ether
For a certain mass of cellulose ether, excessive ash content will reduce the content of effective ingredients in the cellulose ether and affect the application effect of downstream enterprises. The sulfate ash content of cellulose ether is an important measure of its own performance.
Combined with the current production status of existing cellulose ether manufacturers, the ash content of HEC, HPMC and HEMC is usually not more than 5%.
04
Viscosity of cellulose ether
The water retention and thickening effects of cellulose ether mainly depend on the viscosity of the cellulose ether itself and the amount added to the slurry.
05
PH value of cellulose ether
The viscosity of cellulose ether gradually decreases at higher temperatures or after long-term storage, especially in the case of high-viscosity products. Therefore, the pH needs to be limited.
Generally, the pH range of cellulose ether is controlled to be 5-9.
06
Light transmittance of cellulose ether
The light transmittance of cellulose ether directly affects its application effect in building materials.
The main factors affecting the light transmittance of cellulose ether are: the quality of raw materials; the effect of alkalization; the process ratio; the solvent ratio; and the effect of neutralization.
According to the effect of use, the light transmittance of cellulose ether should not be less than 80%.
07
Gel temperature of cellulose ether
Cellulose ether is mainly used as a viscosity enhancer, plasticizer and water retention agent in cement products, so viscosity and gel temperature are important indicators of cellulose ether.
The gel temperature is used to determine the type of cellulose ether and is related to the degree of substitution of the cellulose ether.
In addition, salts and impurities can also affect the gel temperature.
When the temperature of the solution increases, the cellulose ether polymer gradually loses water, and the viscosity of the solution decreases. When the gel point is reached, the polymer is completely dehydrated and a gel is formed. Therefore, the temperature in cement products is usually controlled below the initial gel temperature. Under these conditions, the lower the temperature, the higher the viscosity and the more obvious the effect of thickening and water retention.