High purity magnesium oxide can be used as filler in paints, paper and cosmetics, filler and reinforcing agent in plastics and rubber and auxiliary material in various electronic materials due to its high dispersibility.
When n=0 and 1, the CMC values are 1.58×10-°mol/L and 1.35×10-mol/L, respectively, but after adding counterion KI (0.1mol/L), the CMC values decrease to 9.00×10-mol/L and 4.12×101 mol/L, the corresponding surface adsorption capacity increases, and the molecular cross-sectional area decreases. These phenomena all indicate that the charge repulsion in the polar groups is weakened in the presence of counterions, and the surface molecules are more closely arranged.
According to the same principle, the use of fluorocarbon surfactants and hydrocarbon surfactants with counterions can greatly reduce the amount of fluorocarbon surfactants, while the solution still retains ptfe coating powder suppliers high surface activity. For example, if sodium perfluorooctanoate and n-octyltrimethylammonium bromide are made into a solution of 1:1 (the total concentration remains unchanged), the surface tension of the mixture does not change much (23.7mN/m), while the amount of fluorosurfactant It has been reduced by 10 times.
Matsuo from Japan studied the mixed solution of perfluorodecanoic acid ammonium anion and perfluorodecanoic acid N, N-dimethylmalonamide quaternary ammonium salt cation and found that in addition to the significant reduction in CMC, the surface tension of the bath solution is also higher than that of the independent test. Time is low. The author has also conducted research on fluorocarbon surfactants containing branched chains, and obtained good results. Especially the research on surfactants using tetrafluoroethylene oligomers as raw materials has greatly reduced the fluorocarbon surfactants. The price provides a reliable basis for further expanding the scope of use.
Properties of fluorocarbon surfactants in organic solvents
As surfactants used in organic solvents, the structure is very different from those used in water. Because in order for a compound to have the function of surface activity, the compound must be an amphiphilic molecule, that is, there are two parts in its structure, one of which is solvophilic and the other part is solvophobic. In the water due to the hydrogen bond, the surfactant molecules are rearranged. As a result, the surfactant molecules are transferred to the surface of the solution, and the hydrophobic part of the molecules leaves the solution, forming micelles on the water surface. But in organic solvents, the situation has changed. A long-chain alkyl group is solvent-hydrophobic in a water system, but it becomes solvent-philic in organic solvents—it can be dissolved in organic solvents. , The result of the arrangement is that the original hydrophobic long chain is dissolved in the organic solvent, while the original hydrophilic polar group part is arranged on the surface of the organic solvent, which leads to a large increase in the surface energy of the organic solvent, that is, to increase its surface energy. Surface Tension.
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