Fluorinated thermoplastics

Advanced Thermoplastics Materials. Thermoplastics and linear plastics of finite molecular weight that can be fabricated into very complex stmctures by hot melt or injection mol ding are different from the thermoset materials that require cross-linking to build up infinite molecular weight to form network (cross-link) stmctures. Advances in thermoplastic engineering materials include amorphous thermoplastics, crystalline thermoplastics, Hquid crystal thermoplastics, and fluorinated thermoplastics (see Engineering plastics). 

Fluorinated olefins, 77 866 Fluorinated organics, production of, 77 847 Fluorinated polyimides, 20 278 Fluorinated thermoplastics, 10 8 Fluorinated titanocycle, 25 118 Fluorinating agents, electrophilic, 77 847 Fluorination, 9 281, 678-679 aromatic ring, 77 866 chlorocarbons, 6 235 direct, 77 864, 882 electrochemical, 77 864—865, 882 of germanium, 72 552 halogen exchange, 77 861-864 selective, 77 831... 

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

Appliance wires require a higher temperature rating (105°C or higher). Therefore, the insulation is made of fluorinated thermoplastics, such as p oly- tetr aflu o r o ethylene (PTFE) or fluorinated ethylene—propylene (FEP). 

During the last two decades, many special fluoropolymers have been developed, such as fluorosilicones fluorinated polyurethanes fluorinated thermoplastic elas-... 

The need for highly fluorinated thermoplastic polymers that, unlike PTFE, could be fabricated by conventional melt-processing methods led to the development of a group of resins that are copolymers of tetrafluoroethylene (TFE) with other perflu-orinated monomers. Commercially, the copolymer of TFE and hexafluoropropylene (HFP) is commonly known as fluorinated ethylene propylene (FEP). Copolymerization of TFE with perfluoropropylvinyl ether (PPVE) leads to PFA resins, and copolymerization of TFE with perfluoromethylvinyl ether (PMVE) produces MFA resins. 

Fluorinated ethylene-propylene is a fully fluorinated thermoplastic with some branching, but it mainly consists of linear chains having the following formula ... 

PTFE is marketed under the tradename of Teflon by DuPont and the tradename Halon by Ausimont USA. It is a fully fluorinated thermoplastic... 

Gore-Tex nonabsorbable monofilament suture is made from a highly crystalhne hnear PIPE. This fully fluorinated thermoplastic is an addition polymer and is formed by the free radical polymerization route in aqueous dispersion under pressure with persulfates and hydrogen peroxide as initiators. The monomer (tetrafluoroethylene) is made from a two-step process the fluorination of chloroform by HF to produce CHClFj which is subsequently dimerized by pyrolysis to form tetrafluoroethylene. FI FE has the highest enthalpy and entropy of polymerization (-156 kJ/mol and -112 J/ mol-deg, respectively) among the vinyls (Joshi and Zwolinski, 1967). Its molecular weight can be as high as 5 x l(p. 

Fully fluorinated elastomers Fully fluorinated thermoplastics... 

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). 

FEP is another fluorinated thermoplast. It is considerably easier to fabricate and is less expensive than PTFE while having basically the same corrosion resistant properties. 

As with other fluorinated thermoplasts FEP is subject to permeation by certain gases, refer to Table 1.3. It is also subject to absorption of certain liquids. Refer to Table 3.24. 

Figure 36 Chemical formulae of fluorinated thermoplastic poly(ether-isoimides) 52 and 54, and poly(ether-imides) 53 and 55 used to prepare heat-resistant, flexible...

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. 

Some fluoropolymers prepared by DT with iodo-compounds have already been commercialized such as Daiel, Viton, and Technoflon. Such fluoroelastomers may find applications in high technology such as in O-rings, gaskets, hoses, transportation, medical devices, and electronics. The control of the architecture and functionality of the polymer chains makes possible the preparation of peroxide curable fiuoroelastomer with improved properties as well as the development of advanced fluorinated thermoplastic elastomers. Another application of functional fluoropolymers prepared by DT with iodo-compounds is the preparation of membranes for fuel cells. 

Tatemoto, M. Shimizu, T. In Modern Fluoropolymers-, Scheirs, J., Ed. Wiley New York, 1997 chapter 30 Fluorinated Thermoplastic Elastomers, 565. 

The serendipitous discovery of polytetrafluoroethylene (PTFE) in 1938 by Roy J. Plunkett [82] and his co-workers at DuPont research laboratories has spurred the development of a variety of fluorine containing polymers, which include fluorosilicones, fluorinated polyurethanes, fluorinated thermoplastic elastomers, etc.. Many of the commercial fluoropolymers are suitable for melt processing via conventional injection molding, screw extrusion and blown film extrusion techniques. 

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