Fluoropolymers development

Figure 3.1 Evolution of fluoropolymer development over time. PCTFE, Polychlorotrifluoroethylene PVDF, poly-vinylidene fluoride PVF, polyvinyl fluoride FEP, fluorinated ethylene propylene copolymer ECTFE, ethylene-chlorotrifluoroethylene copolymer ETFE, ethylene-tetrafluoroethylene copolymer PFA, perfluoroalkoxy copolymer AF, amorphous fluoropolymer.

Another impetus to expansion of this field was the advent of World War 11 and the development of the atomic bomb. The desired isotope of uranium, in the form of UF was prepared by a gaseous diffusion separation process of the mixed isotopes (see Fluorine). UF is extremely reactive and required contact with inert organic materials as process seals and greases. The wartime Manhattan Project successfully developed a family of stable materials for UF service. These early materials later evolved into the current fluorochemical and fluoropolymer materials industry. A detailed description of the fluorine research performed on the Manhattan Project has been pubUshed (2). 

The PVC formulations shown in Table 2 represent typical compounds used by the wine and cable industry. PVC compounders have developed new PVC-based formulations with very good fire and smoke properties (can pass the UL 910 Steiner Tunnel test) that compete with the more expensive fluoropolymers. These can be used in fabricating telecommunication cables usable for plenum area appHcations. 

Non-Metallic Materials Numerous engineering thermoplastics have been commercialised including materials such as polyetherether ketone (PEEK) and polyether sulphate (PES) with much improved thermal/chemical resistance. The usage of FRP equipment has increased, and fluoropolymer lining technology/applications have come of age. Of particular interest is the development of stoved, fluoropolymer coating systems for process industry equipment. 

Further optical oxygen sensors which have been developed are those of [Ir(LI I)(L)](PF6)2 and [Ir(L)2]PF6, LH = 2,6-bis(7 -methyl-4 -phenyl-2 -quinolyl)pyridine, immobilized in a polymeric matrix321, and [Ir( ppy)3]31 immobilized in fluoropolymer film.322... 

This research was an attempt to develop new polymers with the mechanical properties of polyarylene ethers and the dielectric properties of fluoropolymers. After initially testing the viability of the [2n+ 2n] cyclodimerization reaction for preparing high-molecular-weight polymers and testing the dielectric properties of these polymers, two polymers (one thermoplastic and one thermoset) were prepared in larger quantities to evaluate the thermal and mechanical performance of these novel compositions. The high Te thermoset was also quantitatively tested for thermal/oxidative stability. 

Nonstickiness, low friction, low wettability, and high thermal- and chemical-resistance are the major properties of PTFE, which was accidentally discovered in the DuPont laboratories in 1938, and these properties are more or less typical of other fluoropolymers that have been developed since. 

In conclusion, the new recycHng procedures described above offer virtually unhmited possibihties for optimization and catalyst engineering . The lengths and other structural features of the ponytails are easily varied. There are innumerable types of possible fluoropolymer supports, as well many additional classes of fluorous supports. Accordingly, a variety of further refinements and developments can be expected in the near future. 

Jinks, P., and Marsden, S. (1999),The development and performance of a fluoropolymer lined can for suspension metered dose inhaler product, in Fradley, G., Ed., Proceedings of Drug Delivery to the Lungsa X, The Aerosol Society, Portshead, United Kingdom, pp. 177-180. 

The last 20 years have seen enormous progress in the development of high-performance fluoropolymers. Fluorine-containing polyimides stand out as one of the few types of materials that simultaneously possess outstanding thermal stability and mechanical properties, low dielectric permittivity, and thin-film processability. This combination of properties makes them ideal for use as high-performance insulators in electronic devices. 

The fluoropolymer area is an expanding area driven by the growing demands of modern technology and in an article of this length it is possible only to sketch briefly the range of products available or being developed. 

Fluoropolymers. These form one of our oldest and most spectacular families of engineering plastics. Polytetrafluoroethylene was developed by DuPont over two decades ago, and more recently by Allied Chemical, Hoechst, ICI, Pennwalt, and other manufacturers as well. It combines unusually low adhesion and friction, high temperature and flame resistance, excellent electrical properties, and extreme chemical inertness. Its high melting point and melt viscosity make thermoplastic processing extremely difficult, so that many... 

A large body of work has been developed by DeSimone and co-workers on the solubility of fluorinated polymers, especially polyfl,l-dihydroper-fluorooctylacrylate) fPFOA), in C02 (Hsiao et al., 1995 Luna-Barcenas et al., 1998). An excellent example of utilizing creative chemistry to design a C02-soluble polymer, PFOA is one of the very few fluoropolymers that dissolves in C02 at modest temperatures and pressures less than 300 bar. The characteristics needed to make a fluoropolymer soluble in C02 can be ascertained from Figure 7.2, which shows the difference in cloud-point curves for polyfvinylidene fluoride) (PDVF), a statistically random copoly-... 

The great value of the unique characteristics of fluorinated polymers in the development of modern industries has ensured an increasing technological interest since the discovery of the first fluoropolymer, poly(chlorotrifluoro-ethylene) in 1934. Hence, their fields of applications are numerous paints and coatings [10] (for metals [11], wood and leather [12], stone and optical fibers [13, 14]), textile finishings [15], novel elastomers [5, 6, 8], high performance resins, membranes [16, 17], functional materials (for photoresists and optical fibers), biomaterials [18], and thermostable polymers for aerospace. 

Some polymers develop irritating or poisonous vapours upon heating, such as PVC and, in particular, fluoropolymers. 

Fluoropolymers represent a rather specialized group of polymeric materials. Their chemistry is derived from the compounds used in the refrigeration industry, which has been in existence for more than 60 years. In the 1930s, efforts were made to develop nontoxic, inert, low boiling liquid refrigerants mainly for reasons of safety. The developed refrigerants based on compounds of carbon, fluorine, and chlorine, commonly known as freons, quickly became a commercial success. Eventually, they also became widely used as aerosol propellants. 

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

The driving force for the development of THV Fluoroplastic was the requirement for a fluoropolymer that could be used as a coating for polyester fabrics and provide... 

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