High purity magnesium oxide has good flame retardant effect, it can be used with wood chips and shavings to make light weight, sound insulation, heat insulation, refractory fiber board and other refractory materials as well as metal ceramics.
This has been widely used in the preparation of polytetrafluoroethylene.
The selection of surfactants in non-aqueous solutions such as solvents is the same as in aqueous solutions. Certain principles should be followed. From the principle of action on surfactants in aqueous solutions, we have learned that the hydrophilic groups interact with water to be dissolved in water. The hydrophobic part is on the surface of the aqueous solution due to mutual repulsion with water, thereby reducing the surface tension of the water. Based on the same principle, scientists have designed a series of compounds so that one end of the surfactant can be dissolved in organic solvents, such as toluene, diesel, etc., and the other end is a group that is insoluble in organic solvents, and these groups are large. Some are fluorine-containing long carbon chain compounds. The following ptfe wax emulsion are the structures of some compounds that have been found to have surface activity in organic solvents:
In addition, people have conducted in-depth studies on the surface activity of some aryl ether compounds (H FPO) of polyperfluoropropylene oxide (H FPO) in organic solvents. When n=2~5, at 20℃ , Can reduce the surface tension of m-xylene to 12~14mN/m. At the lowest surface tension, the corresponding (H FPO) 2~6―C; H; concentration (mass fraction, %) and CMC value are listed in Table 17-10 ,
Such compounds can significantly reduce the surface tension of xylene (28.6mN/m), and the reduction of surface tension is related to the length of the carbon chain. When n=5, the reduction of surface tension is the largest.
In the polyperfluoropropylene oxide phenyl ether series (H FPO) 2-6-C. H, CH. Among them, when n=6, the surface tension of p-toluene or xylene system has the greatest reduction value (Table 17-11), which may be related to the lipophilic toluene group and the oleophobic polyperfluoropropylene oxide group in the molecule. (H FPO) is related to the matching of.
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