2021-11-12 Pageview:309
High purity magnesium oxide product has the advantages of high purity, fine particle size, large specific surface area and good dispersion. It has excellent alkali resistance and electrical insulation at high temperature, high coefficient of thermal expansion and thermal conductivity, and has good light transmittance.
The solubility of non-ionic fluorocarbon surfactants in organic solvents is much greater than that of ionic surfactants, but its stability is worse than that of carboxylic acid or sulfonic acid type, so non-ionic fluorocarbon surfactants are surface active The agent can not be used in the medium of strong oxidizing agent. In addition to the above-mentioned fluorocarbon surfactants, there are some silicon-containing fluorocarbon surfactants, fluorocarbon surfactants without hydrophilic end groups, and polymer fluorocarbon surfactants. However, due to their The price is quite expensive and the amount is not large, so I won’t introduce it here, and interested readers can refer to the relevant literature.
Properties of fluorocarbon surfactants
Characteristics of fluorine atom
As mentioned in the first section, the fluorocarbon surfactants generated by fluorine atoms completely or partially replacing the hydrophobic part of the corresponding hydrocarbon surfactants have unique “three highs” (high surface activity, high resistance). Thermal stability and high chemical stability), “two hydrophobic” (hydrophobic, oil-repellent) characteristics are caused by the following characteristics of msds ptfe powder fluorine atoms.
Properties of fluorocarbon surfactants in aqueous solution
The surface activity of surfactants is generally expressed by critical micelle concentration (CMC). Critical micelle concentration (CMC) represents the concentration of surfactant required for a specific surfactant to minimize the surface tension of the solution. In fluorocarbon surfactants, since all or part of the hydrogen atoms in its hydrophobic part are replaced by fluorine atoms, so that its surface tension in the aqueous solution is lower, so it has stronger surface activity. For example, at a concentration of 1g/L, the surface tension of sodium octyl sulfonate (CgH yz SO; Na) in an aqueous solution at 20°C is 65 mN/m, while the corresponding sodium perfluorooctyl sulfonate (Ca Fiz SO aN a) Its surface tension is 32mN/m under the same conditions. For hydrocarbon surfactants, in the aqueous solution, the surface tension is reduced to 30~35mN/m, and a surfactant concentration of 0.1% is required. For fluorocarbon surfactants, the surface tension of the aqueous solution is reduced to 30mN/m, which is only It can be done with a concentration of 10~100mg/kg.
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