Fluorostyrene polymers

In addition, diblock copolymers with different 4-X-styrene blocks, denoted as PXS, containing 4-chlorostyrene, 4-bromostyrene, or mixtures of 4-fluorostyrene and styrene, were synthesized. In contrast to poly(4-fluorostyrene), polymers of 4-bromostyrene and 4-chlorostyrene are cross-linkable by ultraviolet irradiation [7-9]. Cross-linked polymers typically show better chemical resistance and thermal stability, which are indispensable properties when used as template material for challenging templating methods. Furthermore, replacing the expensive 4-fluorostyrene... 

A preferable system is poly(p-fluorostyrene) doped into poly(styrene). Since rotations about the 1,4 phenyl axis do not alter the position of the fluorine, the F spin may be regarded as being at the end of a long "bond" to the backbone carbon. In standard RIS theory, this polymer would be treated with dyad statistical weights to automatically take into account conformations of the vinyl monomer unit which are excluded on steric grounds. We have found it more convenient to retain the monad statistical weight structure employed for the poly(methylene) calculations. The calculations reproduce the experimental unperturbed dimensions quite well when a reasonable set of hard sphere exclusion distances is employed. 

Fig. 4. Melting temperatures of crystalline styrene//>-fluorostyrene copolymers I, crystallites with threefold helix II, crystallites with fourfold helix (from Natta, G., etal. J. Polymer Sci. 51, 527 (1961))...

Alternative solid polymer electrolytes are also being evaluated to assess advantages in cost and performance. The Nafion 120 is an extremely stable (and thus long-lived) material under water electrolysis operating conditions. Any alternative SPE considered viable must have equivalent life stability. A radiation-grafted tri-fluorostyrene was extensively evaluated, but demonstrated insufficient operational stability to be considered as a viable alternative. The search for other alternatives is continuing. 

In addition to the above mentioned, there have been reports of other polymers deposited using CVP, but extensive studies have not been done. Reports on 4-fluorostyrenes, ° polypyrrole and epoxy-amine polymers can be foundelsewhere, and are not discussed in detail in this paper. 

REDOR was also applied to examine the structure and dynamics of interfaces of heterogeneous polymer blends. A heterogeneous blend was prepared from [carbonyl- C]polycarbonate and poly(p-fluorostyren-co-styrene) copolymer of p-fluorostylene. The blend was formed by coprecipitation from chloroform into methanol. A fluorine dephased REDOR signal indicates that the 1 polycarbonate chain in 20 exists at the interface, suggesting that the polycarbonate phase is embedded in a continuous polystyrene matrix which is 200 A thick or 400 A in diameter [54],... 

Ballard Advanced Materials Corporation (BAM) ionomers are sulfonated copolymers of trifluorostyrene and substituted tri-fluorostyrene monomers. Ballard Advanced Materials, a subsidiary of Ballard Power Systems, investigated the conducting polymers based on polyphenylquinoxaline (PPQ). These can be sulfonated in a wide range and were referred to as Ballard first-generation (BAMIG) membranes, but these membranes were found to have short durability. To overcome this problem, BAM developed a second generation of advanced membranes... 

Polyfluorostyrenes are described in many publications. A -fluorostyrene can be formed by a cationic mechanism. The material softens at 240-260 °C. An a,, jff -trifluorostyrene can be polymerized by a free-radical mechanism to yield an amorphous polymer that softens at 240 Ring-substimted styrenes apparently polymerize similarly to styrene. Isotacticpoly(o-fluorostyrene) melts at 265 °C. It forms by polymerization with Ziegler-Natta catalysts. The meta analog, however, polymerized under the same conditions, yields an amorphous material. 

Polymer abbreviations PHMA poly-n-hexyl methacrylate, StVPh polystyrene-co-vinylphenol, PFSt poly(o-fluorostyrene-co-p-fluorostyrene), P(S-co-BrS) poly(styiene-co-4-bromostyiene), N-TPI new thermoplastic polyimide (see reference), PPrA poly- -propyl acrylate, PPeA poly-n-pentyl acrylate the rest of the polymer acronyms as usual... 

Maeda Y., Karasz F., MacKnight W., (1984), Effect of Pressure on Phase Behavior in Polymer Blends of Poly (2,6-Dimethyl-1, 4-Phenylene Oxide) and Poly (o-Fluorostyrene-co-/ -Fluorostyrene) Copolymers,... 

Gel permeation chromotograms of some of the polymers were measured with a Waters Association Model 440 Gel Permeation Chromatograph equipped with an absorbance detector. Tetrahydrofuran (THF) was used as a solvent and a calibration based on polyisobutylene standards was u ed. The approximate number and weight averages are Mj =136,000 and M =296,000 for the copolymer having 19.6 mole % a-fluorostyrene Hn=60,200 and 1 =98,000 for th copolymer having 48.1 mole % a-fluorostyrene and 1 =16,400 and M =24,800 for poly-(a-fluorostyrene). A similar poly(a-fluorostyrene) sample that was analyzed earlier using a polystyrene calibration had Mj =4,900 and M =10,400 ... 

The quaternary aromatic carbon resonance of the copolymers (6q=140.8 ppm) is observed as a group of four resonances, the relative intensities of which are influenced by C-F couplings, by sequence distribution effects and probably also by stereosequence distribution effects. In the spectrum of poly(a-fluorostyrene), this resonance region contains two strong signals separated by 28 Hz (1.4 ppm), which corresponds to for this polymer. The... 

Other polymers of the perpendicular dipole type so studied indude poly-(dimethyl oxane) pdy(vinyl chloride) pdystyrene pdy(p-chloro-styrene) °, and poly(p-fluorostyrene) . For vinyl polymers the stereochemistry of placements effects the dipole moment ratio, and hence tacticity is reflected by dipole moment measurements. The statistics of such systems, which are stereochemical copoljnners, can be developed in terms of a stereochemical replication probability Pr whose numerical value guides the probability of isotactic (p, 0.95),... 

Copolymers of different monomeric units that are able to co-crystallize in the same lattice are classic examples of polymer crystals including disorder due to isomorphic substitution of monomeric units in the crystal lattices. This occurs for instance for isotactic butene-3-methylbutene [3] or styrene-o-fluorostyrene [4] copolymers and isotactic [5-8] and syndiotactic [9, 10] propene-butene copolymers, which are crystalline in the whole range of compositions. In these cases the constitutional disorder due to the presence of mono-... 

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