Perfluorinated elastomers

Raw-gum fluorocarbon elastomers are transparent to translucent with molecular weights from approximately 5000 (e.g., VITON LM with waxy consistency) to over 200,000. The most common range of molecular weights for commercial products is 100,000 to 200,000. Polymers with molecular weights over 200,000 (e.g., Kel-F products) are very tough and difficult to process. Elastomers prepared with vinylidene fluoride as comonomer are soluble in certain ketones and esters, copolymers of IFF and propylene in halogenated solvents perfluorinated elastomers are practically insoluble.16... 

Currently, there is concern about the use of ammonium perfluorooctanoate (APFO), also known as C8 , which is necessary for the manufacture of fluorinated plastics and elastomers in water. C8 is a perfluorinated anionic surfactant used as a dispersing agent in the polymerization and copolymerization of many fluoropolymers, including poly(tetrafluoroethylene) (PTFE), poly(vinylidene... 

A new high-performance elastomer, prepared from tetrafluoroethylene (TFE) and perfluoro(methyl vinyl ether) (PMVE), and characterized by outstanding resistance to chemical attack and excellent thermal stability, was reported recently by Barney et al. (I) of our laboratory. That paper described a rubbery perfluorinated dipolymer that could not be crosslinked using ordinary techniques because of its chemical inertness, and also a terpolymer in which an unspecified third monomer was used to introduce active crosslinking sites. 

Ki-aton G1600 SEES Perfluorinated ionomers Phenolic resins Polystyrene, head-to-head Poly(yinyl chloride), head-to-head S tyrene- acrylonitrile Styrene-butadiene elastomers Styrene-methylmethacrylate copolymer Sulfo-ethylene-propylene-diene monomer ionomers Vinylidene fluoride-hexafluoropropylene elastomers Chemigum... 

Thanawala, S.K., Chaudhury, M.K. Surface modification of silicone elastomer using perfluorinated ether. Langmuir 16,1256-1260 (2000)... 

Elastomers which can withstand cryogenic temperatures, (e.g., -320 F) are not readily available. Previously, this Institute reported (3) success in preparing perfluorinated polyurethanes through the reaction between perfluorophenyl diisocyanate and a perfluoropolyether ... 

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. 

The Objective of these, investigations was to prepare perfluorinated polyether elastomers having both good low temperature flexibility and high thennal stability. The ring opening polymerizations of hexafluoropropylene epoxide (HPPO) and octafluoro-isobutylene epoxide (OPIBO) were examined as a potential route to such materials. 

A terpolymer of tetrafluoroethylene (60 mole %), perfluoro(methyl vinyl ether) (VII) and a perfluorinated monomer with a reactive site is also commercially available. The material may be cross-linked to give an elastomer which has very low volume swell in a wide range of solvents and which withstands air oxidation up to 315°C. 

The characteristics of fluoropolymers are summarized in Table 1. Thermal and chemical resistance is in general with most of plastics, elastomers and perfluorinated membranes. Weather resistance with the outdoor durability for more than 20 years is specific for fluorinated paint resins. Surface properties such as water and oil repellency are provided by acrylic polymer-based textile finishes and coatings with long-chain per-fluoroalkyl groups. Electrical properties as well as a low refractive index are important for optoelectronics applications like optical fibers. 

In general, the preparation of ionomers is a straightforward procedure. The particular acid group of interest can be introduced onto the hydrocarbon backbone either by direct copolymerization or post-synthesis reaction. The following five important groups of ionomers illustrate the various methods of preparation. These ionomer families are ethylene-based materials, ionic elastomers, modified polystyrenes, perfluorinated resins and halato-telechelic polymers. 

---