Chlorotrifluoroethylene polymer properties

Hyflon AD amorphous fluoropolymer is used in optical devices, pellicles in semiconductor manufacture, as a dielectric and as a separation membrane. Small amounts of TDD have been used as a modifier in ethylene-chlorotrifluoroethylene polymers to increase stress crack resistance. Minute amounts of TDD are used also as a modifier in polytetrafluoroethylene to improve elastic modulus, reduce creep and permeability and increase transparency. It has been suggested that the much higher reactivity of TDD and other fluorinated dioxoles relative to other modifiers gives a more uniform distribution of the modifier in the polymer chain that results in a greater increase in the desired properties at lower concentration of modifier in the polymer. 

Copolymers of chlorotrifluoroethylene and ethylene were introduced by Allied Chemicals under the trade name Halar in the early 1970s. This is essentially a 1 1 alternating copolymer compounded with stabilising additives. The polymer has mechanical properties more like those of nylon than of typical fluoroplastic, with low creep and very good impact strength. Furthermore the polymers have very good chemical resistance and electrical insulation properties and are resistant to burning. They may be injection moulded or formed into fibres. 

The other major springboard for the fluorocarbon chemical industry was the "Manhattan Project to develop the atomic bomb. This required the large-scale production of highly corrosive elemental fluorine and uranium(VI) fluoride for the separation of the radioactive 235U isotope. Oils capable of resisting these materials were needed to lubricate pumps and compressors, and polymers were needed to provide seals. Peril uorinated alkanes and polymers such as PTFE and poly(chlorotrifluoroethylene) (PCTFE) proved to have the appropriate properties so practical processes had to be developed for production in the quantities required. In 1947 much of this work was declassified and was published in an extensive series of papers3 which described the fundamental chemistry on which the commercial development of various fluoro-organic products, especially fine chemicals, was subsequently based. 

For the current study, the source of PCTFE was Kel-F 6061, a solid homopolymer of chlorotrifluoroethylene, produced by the 3M company. Preliminary studies with other forms of PCTFE indicate that its chemistry is by no means unique. We chose this particular polymer for its insolubility and other physical properties. 

Examples of fluoroplastics include polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), ethylene—chlorotrifluoroethylene (ECTFE), ethylene—tetrafluoroethylene (ETFE), poly(vinylidene fluoride) (PVDF), etc (see Fluorine compounds, organic). These polymers have outstanding electrical properties, such as low power loss and dielectric constant, coupled with very good flame resistance and low smoke emission during fire. Therefore, in spite of their relatively high price, they are used extensively in telecommunication wires, especially for production of plenum cables. Plenum areas provide a convenient, economical way to run electrical wires and cables and to interconnect them throughout nonresidential buildings (14). Development of special flame-retardant low smoke compounds, some based on PVC, have provided lower cost competition to the fluoroplastics for indoors application such as plenum cable, Riser Cables, etc. 

Polychlorotrifluoroethylene (PCTFE) has better mechanical properties than PTFE because the presence of the chlorine atom in the molecule promotes the attractive forces between molecular chains. It also exhibits greater hardness and tensile strength, and considerably higher resistance to cold flow than PTFE. Since the chlorine atom has a greater atomic radius than fluorine, it hinders the close packing possible in PTFE, which results in a lower melting point and reduced propensity of the polymer to crystallize [7]. The chlorine atom present in ethylene chlorotrifluoro-ethylene (ECTEE), a copolymer of ethylene and chlorotrifluoroethylene (CTEE), has a similar effect on the properties of the polymer. 

Chlorotrifluoroethylene monomer serves as a building block for the CTFE telomer oils as well as the solid higher polymer and various copolymers. CFC-113 also may be used in the production of trifluoroethylene monomer by vapor-phase reduction using hydrogen and a precious metal catalyst, usually palladium [reaction (9)]. Copolymers of trifluoroethylene and vinylidene fluoride show interesting piezoelectric properties. 

The arrangement of elements in the molecule, the symmetry of the structure, and the polymer chains degree of branching are as important as the specific elements contained in the molecule. Polymers containing the carbon-hydrogen bonds such as pol5 ropylene and polyethylene, and the carbon-chlorine bonds such as PVC and ethylene chlorotrifluoroethylene are different in the important property of chemical resistance from a fully fluorinated pol)nner such as polytetrafluoroethylene. The latter has a much wider range of corrosion resistance. 

Polychlorotrifluoroethylene Thermoplastic polymer of chlorotrifluoroethylene. Has good transparency, barrier properties, tensile strength, and creep resistance, modest dielectric properties and solvent resistance, and poor processibibty. Processed by extrusion, injection and compression molding, and coating. Used in chemical apparatus, low-temperature seals, films, and internal lubricants. Also called PCTFE. 

Certain polymers, such as poly(vinyl chloride), poly(acrylonitrile), poly-(chlorotrifluoroethylene), and poly(vinyl alcohol), are crystalline as usually prepared, despite the strong possibility of the occurrence of significant stereochemical irregularities. In many instances x-ray diffraction patterns, when used as a criterion, did not definitely support the contention of crystallinity. However, particularly in the cases of poly(vinyl chloride)(54,55) and poly(acrylonitrile),(56) solution and mechanical properties gave substantial evidence of the existence of crystallinity. Subsequent synthesis of these polymers by methods designed to impart a greater amount of chain regularity has confirmed those conclusions.(42,57)... 

Poly(chlorotrifluoroethylene) (PCTFE, Kel-F fluoropolymer) is a thermoplastic semicrystalline polymer with (-CF2CCIF-) repeating units [49], Typically, PCTFE is synthesized via a free radical polymerization using bulk, suspension, or emulsion techniques [50]. Compared with PTFE (Teflon fluoropolymer), which has similar chemical properties, there is asymmetry in the CTFE monomer unit due to the presence of the chlorine atom in CFCl groups. Consequently, the NMR features of PCTFE are more complicated due to the possible monomer- and stereo-sequence variations. Since PCTFE has various distinguished properties, including thermal, chemical, and radiation resistance, low vapor permeability, and electrical insulation [51,52], it has... 

Many high-performance polymer fibres are used in filter media to meet various specific requirements in diverse filtration applications. Filters made from fluoropol-ymer (Polytetrafluoroethylene (PTFE), Polyvinylidene fluoride (PVDF), and Per-fluoroalkoxy alkane (PFA)) fibres, and membranes have inherent, chemical-resistant, and flame-retardant properties, and they are widely employed to filter aggressive chemicals and acids in the manufacture of wafers and microchips in the microelectronics industry. Ethylene ChloroTriFluoroEthylene (E-CTFE) melt blown fabrics have a unique ability to coalesce difficult liquids and can withstand the piranha effect in filtering ozone enriched ultrapure water. Polyphenylene sulfide (PPS) fibres are also chemical resistant, stand high temperature, and are suitable for making baghouse filters. Eilter media made from other high-performance polymer fibres, such as polyamide-imide, polyetherimide (PEI), Polyimide P84 fibre,polyetheretherke-tone, and liquid crystal polymers also appear in the filtration and separation market. 

In semicrystalline dipole electrets, polar crystallites are present in addition to the polar amorphous phase (Fig. 2b). In die technically most interesting semicrystalline dipole electrets such as polyvinyhdene fluoride (PVDF) and its copolymers with trifluoro ethylene (P(VDF-TrFE)) (Lovinger 1983) or hexafluoropropylene (P(VDF-HFP)), odd Nylons 7 and 11, polyureas, polyureflianes (PU), and some liquid crystalline polymers, the crystallites are ferroelectric (Vasudevan et al. 1979 Hattori et al. 1996). The terpolymer poly(vinyhdene-fluoride-trifluoroethylene— chlorotrifluoroethylene) (P(VDF-TrFE-CTFE)) has been shown to have relaxor ferroelectric properties as the CTFE group destabilizes die long-range order of the ferroelectric phase (Xu et al. 2001). 

Polymerization can be designed to improve specific properties of polyvinylidene fluoride. For example, Dohany reported y" ] polymerization of vinylidene fluoride to modify the flow behavior to allow extrusion of the polymer at higher speeds. Polyvinylidene fluoride of this development was produced as a homopolymer or a copolymer containing up to 25% of a comonomer such as tetrafluoroethylene, chlorotrifluoroethylene, and... 

Properties used in the characterization of ethylene chlorotrifluoroethylene (ECTFE) polymers are defined in Table 5.75. ASTM Method D3275 classifies the different types of ECTFE according to the specifications summarized in Table 5.76. 

Table 6.19. Properties of Ausimont Ethylene Chlorotrifluoroethylene (ECTFE) Polymers i...

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