High-temperature polymers fluorine-containing

Qian G (2008) Fluorine-containing polybenzimidazoles for high temperature polymer electrolyte membrane fuel cell applications. PhD Thesis, Rensselaer Polytechnic Institute, Troy, NY... 

Considerable attention has also been devoted to the preparation of fluorine-containing polymers because of their unique properties and high-temperature... 

As part of an effort to develop high-performance, high-temperature-resistant polymers for microelectronics applications, we also recently described a series of both partially fluorinated and nonfluorinated poly(aryl ether ketone)s containing amide, amide-imide, cyano oxadizole, or pyridazine groups and characterized their thermal and electrical properties.11... 

Much attention has been paid to the synthesis of fluorine-containing condensation polymers because of their unique properties (43) and different classes of polymers including polyethers, polyesters, polycarbonates, polyamides, polyurethanes, polyimides, polybenzimidazoles, and epoxy prepolymers containing pendent or backbone-incorporated bis-trifluoromethyl groups have been developed. These polymers exhibit promise as film formers, gas separation membranes, seals, soluble polymers, coatings, adhesives, and in other high temperature applications (103,104). Such polymers show increased solubility, glass-transition temperature, flame resistance, thermal stability, oxidation and environmental stability, decreased color, crystallinity, dielectric constant, and water absorption. 

Most commercial fluorocarbon elastomers have brittle points between -25°C (-13°F) and -40°C (-40°F). The low-temperature flexibility depends on the chemical structure of the polymer and cannot be improved markedly by compounding. The use of plasticizers may help somewhat, but at a cost of reduced heat stability and worsened aging. Peroxide-curable polymers may be blended with fluorosilicones, but such blends exhibit considerably lower high-temperature stability and solvent resistance and are considerably more expensive than the pure fluorocarbon polymer. Viton GLT is a product with a low brittle point of -51°C (-59°F) [48]. Tecnoflon for containing a stable fluorinated amide plasticizer reportedly exhibits improved low-temperature hardness, brittle point, and compression set without sacrificing physical properties [66]. Low-temperature characteristics of selected fluorocarbon elastomers are listed in Table 5.13 [9]. 

The first polymer containing fluorinated arylborane substituents has recently been reported. The highly functionalized soluble polymer (195) was obtained in good yield by treatment of poly(4-dibromoborylstyrene) with equimolar amounts of pentafluorophenylcopper at low temperature. Polymer (195) shows a slightly lower Lewis acidity than the perfluorinated borane B(C6F5)3 as determined by complex-ation with crotonaldehyde (equation 41). However, in this... 

VFa/HFP/TPE Reactivity. It is well known to those f2miliar wi the characteristics of fluoroelastomers that polymers of unusu dly high fluorine content, e.g., VF2/HFP/TFE terpol rs tAiich contain about 45 wt% VF2 and about equal amounts of HFP and TFE, exhibit some compromise in cure rate and high-temperature compression set resistance in order to achieve their increased fluid resistance. In order to determine idiether there are discernible chemical reasons for these differences, the behavior of VF2/HEP/IFE polymers toward bases in solution was investigated. 

All the polymers that contain fluorine side groups in the molecular structure have excellent high-temperature stability and chemical resistance. Polytetrafluoroethy-... 

Fluoroelastomers are fluorine-containing hydrocarbon polymers with a saturated structure obtained by polymerizing fluorinated monomers such as vinylidene fluoride, hexafluoropropene, and tetrafluoroethylene. The result is a high-performance s)mthetic rubber with exceptional resistance to oils and chemicals at elevated temperatures. Initially, this material was used to produce O-rings for use in severe conditions. Although this remains a major area of application, these compoimds have found wide use in other applications because of their chemical resistance at high temperatures and other desirable properties. 

Chuang SW, Hsu SL (2006) Synthesis and properties of a new fluorine-containing polybenzimidazole for high-temperature fuel cells applications. J Polym Sci Pol Chem 44 4508-4513... 

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