The nature and role of methyl cellulose

Methylcellulose is also known as cellulose methyl ether, referred to as MC. It is a long-chain substituted cellulose in which 27% to 32% of hydroxyl groups are present in the form of methoxy groups, and the degree of substitution affects the physical properties of methyl cellulose, such as solubility. . It is generally white or off-white fibrous or granulated powder at room temperature; odorless and tasteless. It can swell into a clear or slightly turbid colloidal solution in water.

Methylcellulose properties:

It rapidly disperses and swells in hot water at 80-90 ° C, dissolves rapidly after cooling, and the aqueous solution is quite stable at normal temperature. It gels at high temperature, and the gel can change with the solution according to the temperature. It has excellent wettability, dispersibility, adhesion, thickening, emulsifying, water retention and film forming properties, as well as impermeability to grease. The film formed has excellent toughness, flexibility and transparency. Because it is nonionic, it can be compatible with other emulsifiers, but it is easy to salt out and the solution is stable in the range of PH2-12. Do not dissolve in absolute ethanol, chloroform or ether.

Methylcellulose effect:

Methylcellulose itself is a polymeric surfactant and also acts as an anionic surfactant. The aqueous solution has the functions of thickening, bonding, film formation, moisture retention, emulsification, suspension, etc., and is generally used as a retarder, a polymeric dispersant and a thickener. Used as a thickener for water-soluble adhesives, such as thickeners for neoprene latex. It can also be used as a dispersing agent, emulsifier and stabilizer for vinyl chloride and styrene suspension polymerization. The MC of DS = 2.4 to 2.7 is dissolved in a polar organic solvent to prevent volatilization of the solvent (methylene chloride-ethanol mixture). Carboxymethylcellulose, which is present as an emulsifier in the form of an alkali metal salt and an ammonium salt, is soluble in water, and food grade methylcellulose can be used as a food additive.

Precautions:

Methylcellulose powder is stable and slightly hygroscopic. It should be stored in an airtight container and stored in a cool dry place.

The methylcellulose solution is stable to dilute acids and bases having a pH of 3 to 11 at room temperature, and is easily destroyed by microorganisms and spoiled. Therefore, the solution should be added with a preservative or autoclaved. The change in viscosity of the solution after autoclaving is related to the pH of the solution. A solution having a pH of <4 has a viscosity reduction of more than 20% after autoclaving.

Beijing Suo Lai Bao Technology Co., Ltd. has the spot product methyl cellulose (M8070), and a similar product, sodium carboxymethyl cellulose (C8621). Carboxymethyl cellulose is more hydrophilic than methyl cellulose. As a biochemical reagent for scientific research, both methyl cellulose and carboxymethyl cellulose can be used as a molecular surfactant, an emulsifier, and the like.

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