Fluorinated diols, polyurethanes

In the same way, O Rear et al. [32] obtained prepolymers diols from a stoechiometric amount of diol and diglycidic ether and these products led to fluorinated polyurethanes. 

Such diisocyanates can lead to polyurethanes. The first fluorinated polyurethane was patented in 1958 [74], An interesting survey [75] details the comparison of the reactivity of fluorinated diols about that of non halogenated ones for the preparation of such polymers. The first one which contained fluorine was synthesized by reaction of hexafluoropentanediol and hexamethylene diisocyanate [76] ... 

Furthermore, Wall reviewed the fluorinated polyurethanes prepared from polyesters of fluorinated diols [79], from fluorinated polyethers [80] and detailed their properties [81]. 

Linear aliphatic fluorinated polyurethanes have been tested with respect to the location of the fluorine atoms in the diol or diisocyanate component. Fluorine atoms introduced into the diisocyanate unit increase the stability of the urethane group, but the presence of these atoms in the diol unit favours dissociation of the urethane group to monomer. Comparison of PTFE and perfluoroamidine polymers shows that introduction of triazine rings in fluoromethylene chains enhances their stability. 

Polyurethane-based FTPEs are produced by reacting fluorinated polyether diols with aromatic disocyanates. The resulting block copolymers contain fluorinated polyether soft segments.68 Another possible method of preparation of fluorinated TPE is dynamic vulcanization. Examples are a blend of a perfluoroplastic and a perfluoroelastomer containing curing sites or a combination of VDF-based fluo-roelastomers and thermoplastics, such as polyamides, polybutylene terephtalate, and polyphenylene sulhde.69 70... 

Then, polyurethanes based on aromatic diisocyanates were prepared. The same fluorinated diol was involved in the synthesis of such polymers with 3,5-tolylene diisocyanate and with a mixture of 2,4-tolylene diisocyanate and 3,3 -bitolylene-4,4 -diisocyanate [77]. 

Wall [11] produced an excellent review of fluorinated aromatic and aliphatic polyurethanes and their applications, even using a perfluorinated diisocyanate and a fluorinated diol as follows ... 

Polyurethane-based FTPEs are produced by reacting fluorinated polyether diols with aromatic diisocyanates. The resulting block copolymers contain fluorinated... 

Solution Polymerization. Fluorinated diols lb and Ic react with hexamethylene diisocyanate in THF in the presence of dibutyltin dilaurate catalyst to give polyurethanes having structures 4 and 6 (Scheme 1). In a typical synthesis, 1.7 X 10 mol of dibutyltin dilaurate was added to a solution of 1.91 X 10 mol of hexamethylene diisocyanate (HDI, 2) in 0.5 mL of THF. A solution of 1.250 g of Ic in 1.5 niL of THF was then added. The solution was stirred for 2 hours at 25 C, after which time the solution was very viscous. THF (22 mL) was added and the mixture was heated at 68 C. The soluble fraction was decanted from the insoluble fraction. The soluble fraction was poured into 500 mL of methanol, yielding a white precipitate. After... 

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