Rdp Redispersible Polymer Powder for Tile Adhesive EIFSJune 6th 2023
Generally speaking, the product descriptions provided by cellulose ether manufacturers will contain the following indicators: appearance, degree of substitution of viscosity groups, fineness, effective substance content (purity), moisture content, recommended areas and dosage, etc. These performance indicators can reveal part of the role of cellulose ethers, but when comparing and selecting cellulose ethers, the chemical composition, degree of modification, degree of etherification, NaCl content, DS value and other aspects should also be considered.
The viscosity of cellulose ether affects its water retention, thickening, retardation and other aspects. Therefore, it is an important indicator for the examination and selection of cellulose ether.
Before discussing the viscosity of cellulose ether, it should be noted that there are four commonly used methods for testing the viscosity of cellulose ether: Brookfield, Hakke, Hppler, and rotational viscometer. The equipment, solution concentration, and test environment used in the four methods are different. Therefore, the results of the same MC solution tested by the four methods are also very different. Even for the same solution, using the same method and testing under different environmental conditions, the viscosity results are also different. Therefore, when describing the viscosity of a cellulose ether, it is necessary to indicate at the same time the environmental conditions such as the test method, solution concentration, rotor, rotation speed, test temperature and humidity, etc., and this viscosity value is valuable. It is meaningless to simply say “what is the viscosity of a certain MC”
It is well known that cellulose ethers are easily eroded by cellulosic mold. When mold erodes the cellulose ether, the first thing it attacks is the unetherified glucose unit in the cellulose ether. As a linear compound, once the glucose unit is destroyed, the entire molecular chain is broken, and the viscosity of the product will drop sharply. After the glucose unit is etherified, the mold will not easily erode the molecular chain. Therefore, the higher the degree of etherification substitution (DS) of the cellulose ether, the higher its stability.
Take Tylose MC product MH100001p6 as an example. The product specification clearly states that the DS value is 1.70 (water-soluble MC has a DS value less than 2), which can indicate that the product has high product stability.