Thermoplastic perfluorinated

Fluorinated thermoplastics fully perfluorinated thermoplastics (PTFE orTFE,... 

PTFE and other perfluorinated thermoplastics are not sensitive to moisture or UV. Stabilization is not needed. 

Table 4.63 Perfluorinated thermoplastics examples of chemical beharionr at room temperature...

Among the above chemicals, less than ten are harmful for the three perfluorinated thermoplastics. 

Perfluorinated thermoplastics are generally rather permeable, especially PTFE because of the processing methods used. 

Fire resistance is naturally excellent but perfluorinated thermoplastics release corrosive and toxic fumes. Oxygen indices are at least 95 and UL94 rating is VO. 

Perfluorinated thermoplastics are excellent insulators even in wet environments, with high resistivities and dielectric strengths, and very low loss factors. 

In some cases, used perfluorinated fluoropolymers (e.g., PTFE, PFA) are recycled by special cleaning processes and are ending up in the Repro-PTFE or micropowder-PTFE-market. Perfluorinated thermoplasts (e.g., PFA) are reused in applications where the quality requirements (e.g., lot traceability) are much lower. Overall, the lion s share of used fluoropolymers is, however, ending up in landfills, in incineration plants, or in blast furnaces. Communal waste incinerators can tolerate only very limited amounts of fluoropolymers due to the high corrosion due to hydrofluoric acid formed in the process. 

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). 

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. 

Perfluorinated/Partially Fluorinated Thermoplasts/Elastomers Clean, unfilled, unpigmented, and uncured scrap materials from manufacturing and processing of perfluorinated/partially fluorinated thermoplasts or elastomers are generated in the low percent range. Nearly all of these materials are recycled back into the different processes the end use properties are almost unaffected. 

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. 

Perfluoropolymers bum, but do not continue to bum when the flame is removed. All perfluorinated fluoropolymers pass a UL 83 vertical flame test and are classified 94 V-0 according to Underwriters Laboratory (UL) in their burning test classification for polymeric materials. Limiting oxygen index (LOI) by ASTM D2863 is 95% or higher for PTFE, PFA, FEP, and PCTFE. Partially fluorinated fluoropolymers are more flame resistant than other thermoplastics but not quite as resistant as the perfluorinated fluoropolymers, as evidenced by their lower EOI values. PVDF, ETFE, and ECTFE meet UE 94 V-0. Table 13.48 lists the EOI of various fluoropolymers. 

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