Thermoplastic perfluorinated polymer

TEFLON" FEP was commercialized in 1959. At that time there appeared to be no hope of synthesis of a thermoplastic perfluorinated polymer of any structure other than FEP. Within two years the situation had changed as the result of a series of unexpected discoveries. For several years, research on the synthesis of perfluorocarbon epoxides had been underway in Du Pont, culminating in the discovery of a route to hexafluoropropylene epoxide (HFP0 )[5]. By 1960 sufficient HFPO had been made to permit exploration of its polymerization. This work shortly turned up an unusual polymerization system consisting of CsF initiator and polyethylene glycol ether solvent. Under the proper conditions this same system could be used to effect the condensation of HFPO with perfluorocarbon acid fluorides to produce perfluoroalkoxypropionyl fluorides [6]. These intermediates could be readily converted to perfluoroalkyl vinyl ethers by pyrolysis of their acid forms. 

The catalyst blends were prepared by coextruding the thermoplastic form of the polymers. Catalyst A is Nation in the sulfonic acid form and catalyst B is a blend of Nafion in the sulfonic acid form and a perfluorinated polymer containing CO2H groups. Catalyst C is a blend of Nafion in the sulfonic acid form and Teflon FEP and Catalyst D is a blend of Nafion in the sulfonic acid form and Teflon . The oligomerization of isobutylene in toluene at 110°C was used to measure the activity of Catalysts A-D. Table 3 summarizes the results. 

Perfluorinated Polymers, Polytetrafluoroethylene Polyamides, Aromatic Polyamides, Plastics Polyarylates Poly(arylene sufide)s Polycarbonates Cyclohexanedimethanol Polyesters Polyesters, Main Chain Aromatic Polyesters, Thermoplastic Polyethers, Aromatic Poly(ethylene naph-thanoate) Polyimides Polyketones Poly(phenylene ether) Polysulfones Poly(trimethylene terephthalate) Rigid Rod Polymers Syndiotactic Polystyrene . 

Fully Fluorinated Polymers. The radiation chemistry of fully fluorinated polymers shows remarkable temperature dependence, with all of the fluorinated thermoplastics undergoing degradation, ie, chain scission, at ambient temperatures, but with an increasing yield of cross-linking reactions at elevated temperatures. Over the past 10 years, this has led to renewed interest in the radiation chemistry and applications of these materials (see Perfluorinated Polymers, Polytetrafluoroethylene). 

Initial results, then, show a great promise for these perfluorin-ated thermoplastic resins as hot-melt, thin-film adhesives. Their unique set of physical and chemical properties gives them a range of applicability few other polymers can begin to match. Work with them should continue with emphasis on their role in water-impervious joints. Hopefully such an investigation should lead to a better understanding needed for their optimum utilization. 

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