Carboxymethyl cellulose

  Carboxymethyl cellulose is a carboxymethyl group substituted product of cellulose. Depending on its molecular weight or degree of substitution, it can be a completely soluble or insoluble polymer, the latter of which can serve as a weak acid cation exchange agent for separating neutral or alkaline proteins, etc. Carboxymethyl cellulose can form high-viscosity colloids, solutions, and has properties such as adhesion, thickening, flow, emulsification, dispersion, excipient, moisture retention, colloid protection, film formation, acid resistance, salt resistance, and suspension, and is physiologically harmless, thus widely used in the production of food, medicine, daily chemicals, petroleum, papermaking, textiles, construction, and other fields.

  Carboxymethyl cellulose (CMC) appears as a white or slightly yellow fibrous powder or white powder, odorless and tasteless, non-toxic; it is easily soluble in cold or hot water, forming a gel-like solution that is neutral or slightly alkaline, insoluble in organic solvents such as ethanol, ether, isopropanol, acetone, etc., but soluble in ethanol or acetone solutions containing 60% water. It has hygroscopicity, is stable to light and heat, and its viscosity decreases with increasing temperature. The solution is stable at a pH value of 2 to 10; below pH 2, solid precipitation occurs, and above pH 10, viscosity decreases. The discoloration temperature is 227°C, the carbonization temperature is 252°C, and the surface tension of a 2% aqueous solution is 71 mn/n.

Applications: Carboxymethyl cellulose sodium (CMC) is one of the largest production, widely used, and convenient products among cellulose ethers, commonly known as "industrial monosodium glutamate".

  One of the important characteristics of CMC is the formation of high-viscosity colloids, solutions, adhesion, thickening, flow, emulsification dispersion, endowment, water retention, protection of colloids, film formation, acid resistance, salt resistance, and suspension, and it is physiologically harmless. Therefore, it is widely used in the production fields of food, medicine, daily chemicals, petroleum, papermaking, textiles, construction, and more.

CMC quality indicators, main Applications, performance, characteristics (Note: Viscosity is measured using NDJ-79 viscometer, 2% aqueous solution, 25°C)

  Mix CMC directly with water to prepare a paste-like gel solution for later use. When preparing CMC gel, first add a certain amount of clean water to the mixing tank with a stirring device, and while the stirring device is on, slowly and evenly sprinkle CMC into the mixing tank, stirring continuously to ensure that CMC and water are fully integrated and that CMC can dissolve completely. The reason for evenly sprinkling and continuously stirring when dissolving CMC is to "prevent CMC from clumping or agglomerating when it meets water, which reduces the amount of CMC that can dissolve," and to increase the dissolution speed of CMC. The time for stirring and the time for CMC to completely dissolve are not the same; they are two different concepts. Generally speaking, the stirring time is much shorter than the time required for CMC to completely dissolve, and the time required for both depends on the specific situation.

The basis for determining the stirring time is: when CMC is evenly dispersed in water and there are no obvious large clumps present, stirring can be stopped, allowing CMC and water to permeate and merge with each other in a static state.

The basis for determining the time required for CMC to completely dissolve includes the following aspects:

(1) CMC and water are completely bonded, with no solid-liquid separation occurring between them;

(2) The mixed gel is in a uniform and consistent state, with a smooth and flat surface;

(3) The mixed gel is close to colorless and transparent, with no particulate matter in the gel. The time required from when CMC is added to the mixing tank and mixed with water until CMC is completely dissolved is between 10 to 20 hours.