Judge the quality of hydroxypropyl methylcellulose

Nowadays, there are more and more hydroxypropyl carboxymethyl cellulose sales markets, and the prices are not balanced. How to easily and quickly determine the quality of hydroxypropyl methyl cellulose has long become a crucial issue! So how to judge the quality of hydroxypropyl methylcellulose? The first thing to look at is the whiteness of hydroxypropyl cellulose; although the whiteness is not clear whether HPMC is suitable for application, some unscrupulous manufacturers will add a whitening agent during the processing process, which will harm its quality. But generally speaking, most of the fine cellulose ethers have better whiteness.

Secondly, it depends on the fineness of hydroxypropyl methylcellulose: the particle size of hydroxypropyl carboxymethyl cellulose is 80-100 mesh, 120 mesh is less, and hydroxyethyl cellulose HECHPMC is about 100 mesh. Most of hpmc is 60-80 mesh, generally the softer the methyl cellulose, the better the dispersion.

The clarity of the cellulose ether in the solution: Put HPMC in water to produce a fully transparent colloidal solution. The higher the clarity and the higher the clarity, the lower the insoluble chemicals.

When the product is heated, it is gelled or pooled, and then melted. It is water-repellent. Concrete is the key bonding and demulsification raw material for water-resistant putty powder. The principle of water resistance is as follows: Redispersible latex powder and cement are continuously reverted to the original emulsion form during the mixing process with water. Latex particles Evenly dispersed in the cement paste. After the cement meets water, the hydration reaction starts, the Ca(OH)2 solution is saturated and crystals are precipitated. At the same time, ettringite crystals and hydrated calcium silicate colloids are formed, and the latex particles are deposited on On the gel and unhydrated cement particles, as the hydration reaction progresses, hydration products continue to increase, and the latex particles gradually gather in the voids of inorganic materials such as cement, and form a tightly packed layer on the surface of the cement gel. Due to the gradual decrease of dry moisture, the redispersed latex particles closely packed in the gel and voids agglomerate to form a continuous film, forming a mixture with the cement paste interpenetrating the matrix, and making the cement paste and other powders The aggregates are glued to each other.

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