Perfluoropolyethers properties

Two of the perfluoropolyether fluid stmctures yet to be commercialized are interesting. The first stmcture is a strictly alternating copolymer of ethylene oxide and methylene oxide, which has the longest Hquid range of any molecule containing carbon (40). The second stmcture is the perfluoromethylene oxide polyether which has low temperature Hquid properties down to —120° C ... 

Reaction of TYZOR TPT with polyperfluoroalkylene ethers containing a carbonyl group produces a complex that is an excellent surface-treating agent, imparting improved surface wettabiUty and anticorrosion properties to metal surfaces (144). These complexes can be used by themselves, or as additives to perfluoropolyethers as vacuum pump oils, lubricant oils, or mold release agents. 

Functional perfluoropolyethers11 (Figure 14.7) can also be prepared by direct fluorination in high yields. Difunctional perfluoropolyethers based on fluorinated polyethylene glycol) are of particular interest as possible precursors for elastomers, which should have outstanding high-temperature and low-temperature properties. 

The first heavier than water internal tamponade was introduced in 1987 by Chang with LPFC [1]. The two perfluorocarbons most used are perfluorooctane and perfluorodecaline. Perfluorotributylamine, perfluoropolyether, perfluorooctyl-bromide and perfluorophenanthrene are less used. LPFC are transparent fluids and are not miscible in water and their main characteristic is their high density (1.76-2.03) [2], Their properties are summarised in Table 1. 

Although supercritical CO2 is an effective solvent for oils, fats, and similar substances, it is a poor one for nonvolatile hydrophilic (water-loving) substances such as proteins or metallic salts. Adding water as such to the supercritical CO2 is of little help, as the solubility of water in it is limited. Johnson and co-workers216 overcame the latter limitation by forming water-in-C02 emulsions with the aid of an added nontoxic perfluoropolyether surfactant that forms reverse micelles around the water microdroplets, in effect combining the special properties of supercritical CO2 with the solvent power of water. These emulsions can dissolve a variety of biomolecules at near-ambient temperatures, without loss of their biological activity. 

G. Marchionni, G. Ajroldi, P. Cinquina, E. Tampellini, and G. Pezzin, Physical properties of perfluoropolyethers Dependence on composition and molecular weight, Polym. Eng. Sci. 30, 829-834 (1990). 

D. Sianesi, V. Zamboni, R. Fontanelli, and M. Binaghi, Perfluoropolyethers Their physical properties and behavior at high and low temperatures, Wear 18, 85-100 (1971). 

P. M. Cotts, Solution properties of a group of perfluoropolyethers comparison of unperturbed dimensions, Macromolecules 27, 6487-6491 (1994). 

Q. Guo, S. Izumisawa, M. S. Jhon, and Y. T. Hsia, Transport properties of nanoscale perfluoropolyether films, IEEE Trans. Magh. (in press). 

The surface treatment agent perfluoropolyether-modified silane, (III), was prepared by the author [1] and had improved water/oil repellency, chemical resistance, and antifouling properties. 

Jhon, M.S. Physicochemical properties of nano-structured perfluoropolyether films. In Advances... 

G. Mai chioni, G. Ajioldi, G. Pezzin, Structure-Property Relationships in Perfluoropolyethers A Family of Polymeric Oils in Comprehensive Polymer Science (G. Allen, S. L. Aggaiwal, S. Russo eds.), 2nd suppl., Pergamon, 1996, p. 347-388. 

Morita M, Kubo M, Matsumoto M. Interfacial properties and emulsification in systems of perfluoropolyether/nonfluorinated oil/partially fluorinated oligomeric and polymeric compounds. Colloids Surfaces A Physicochem Eng Aspects 1996 109 183-194. 

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