Polyols fluorinated

The most frequently used method to prepare fluorourethanes commercially is the well-known addition reaction of polyisocyanates with polyols. Fluorine is most frequently introduced through the polyol component, since fluorinated polyisocyanates are relatively difficult to obtain and considerably more expensive than the nonfluorinated kind.34 Examples of fluorinated alcohols for polyurethane resins are listed in Table 8.3.35... 

De-icing compositions for the removal of ice or for prevention of its reformation on automobile windshields are prepared from 1 part polyol, 1 part alcohol, and 0.05 part fluorinated surfactant, e.g., ammonium salts of mono- and bisfluoroalkyl phosphates and their complexes with aliphatic quaternary methyl sulfates [287]. 

Related to the nitrile oxide cycloadditions presented in Scheme 6.206 are 1,3-dipolar cycloaddition reactions of nitrones with alkenes leading to isoxazolidines. The group of Comes-Franchini has described cycloadditions of (Z)-a-phenyl-N-methylnitrone with allylic fluorides leading to enantiopure fluorine-containing isoxazolidines, and ultimately to amino polyols (Scheme 6.207) [374]. The reactions were carried out under solvent-free conditions in the presence of 5 mol% of either scandium(III) or indium(III) triflate. In the racemic series, an optimized 74% yield of an exo/endo mixture of cycloadducts was obtained within 15 min at 100 °C. In the case of the enantiopure allyl fluoride, a similar product distribution was achieved after 25 min at 100 °C. Reduction of the isoxazolidine cycloadducts with lithium aluminum hydride provided fluorinated enantiopure polyols of pharmaceutical interest possessing four stereocenters. 

Its average molecular weight is 2000 400 with functionality 2.0. The cost of these fluorinated polyols is high. However, PU elastomers with unique chemical resistance and other exceptional properties are produced. 

Fluorinated polyols with molecular weights between 500 and 10,000, which are preferred for most applications ... 

The addition of small amounts of fluorinated polyols to conventional aqueous polyurethane coatings can improve their water resistance and mechanical properties considerably 47 FEVE resins can be applied as water-based coatings and cured at 160°C (320°F) for 25 min to produce coatings with high gloss and good water and weather resistance.48 They may also be cured with water-based hardeners.49... 

Elastomers based on fluorinated polyurethanes exhibit good mechanical properties and resistance to solvents, chemicals, cold, and heat.54 Formulations for fluoroure-thane elastomers are frequently modified with siloxanes to optimize certain properties.55 FEVE-based polyols are used to manufacture elastomeric automobile bumpers and interior trim components.56... 

The Test method A, based on 19fluorine NMR spectroscopy, is based on the derivatisation of terminal oligo-polyol groups with trifluoroacetic anhydride. The fluorine atoms of the trifloroacetic esters of primary hydroxyls have a totally different chemical shift as compared to the fluorine atoms of the secondary hydroxyl trifluoroacetic esters. 

Polymeric (ethyl cellulose, fluorinated polyol, phthalo-cyanins) films on SAW " devices and chemiresist transducers... 

Fluorine containing polyols were derivatized with lEM by Newell and Wolf (26) to give novel radiation-hardenable urethane acrylates which are especially useful as adhesives for electro-optical components or as protective coatings. 

Irradiated PVDF and poly(VDF-co-TrFE) copolymer possess ferroelectric properties that allow the use of such fluorinated polymer in the domain of captors, sensors, and detectors [47,194]. Another interesting property of crosslinked poly(VDF-co-HFP) copolymer is their insolubihty in organic solvent [195]. Cured fluorinated polymers can be processed as membranes for many electrochemical applications such as fuel cell and batteries [196]. For example, a poly(VDF-co-HFP) copolymer has been crossUnked with various systems such as polyols [197], by irradiation with electron beam or y-rays [197] or with aliphatic amines [198] in order to elaborate a solid polymer electrolyte for non aqueous lithium battery [197,198]. This electrolyte is particularly interesting for its ionic conductivity, its adhesion with an electro-conductive substrate and also remarkably enhanced heat resistance. 

Polymeric fluorinated surfactants (1) have a fluorinated backbone or (2) contain perfluroalkyl groups, as pendant perfluoroalkyl groups attached directly or indirectly to the polymer backbone, or as one or two fluorinated end groups of the polymer. A perfluoroalkyl tail can be attached to poly(tris(hydroxymethyl)-acrylamidomethane or to a natural product, such as a sugar, polyol, and so forth [180]. A fluorinated group may be attached to a poly(oxyethylene) chain —CH2CH2O—, to an ethylene oxide-propylene oxide block polymer, or to an acrylic comonomer. 

Fluorinated surfactants can lower the interfacial tension between a fluorocarbon, such as per perfluorodecalin, and water to as low as 1 mN/m. This suggests that fluorinated surfactants should be effective emulsifiers for biomedical fluorochemicals [42]. The first fluorinated surfactants [112-121] used in fluorochemical emulsions included potassium oleate, a perfluorinated amine oxide [115,116], a nonionic fluorinated surfactant derived from perfluoroalcohol [117], a fluorinated surfactant with two perfluoroalkyl end groups [118], and perfluo-roalkylated polyols [119]. However, the toxicity of these fluorinated surfactants has hindered their intravascular use. 

Because Pluronic F-68 has caused adverse reactions in some patients, fluorinated surfactants are being developed to replace Pluronic F-68 as the sole emulsifier. Attempts to use perfluoroalkylated surfactants derived from galactose, glucose, maltose, and related polyols as single surfactants were unsuccessful [125,127,139,143,155]. However, a study of perfluoroalkylated fatty acid monoesters of trehalose and sucrose (Fig. 13) [144,145] showed that 6-0-[3 -(per-fluorooctyl) propanoyl)-o ,Q -trehalose can emulsify perfluorodecalin and form stable emulsions in the absence of Pluronic F-68. 

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