Phenylenes Polyphenylenes

Billow and Miller [187] also reported fairly similar results for poly(phenylene)s prepared from mixtures of terphenyls. Poly(m-phenylene) [188], phenyl-substituted polyphenylene [189] and perfluoropolyphenylene [190] have thermal and oxidative stabilities similar to that of poly(p-phenylene). Polyphenylenes synthesized by Wurtz-Fittig and Ullmann reactions were reported to withstand heating up to 500°-550°C [187,191,192]. Electrically conductive azo derivatives of polyphenylene (cTo= l-40ohm cm ) were stable up to 300°C without any noticeable decomposition, whereas the conductive block co-polymer of poly-phenylene with p-diethynylbenezene could withstand heating for many hours at 400°-450°C [I], Poly(p-phenylene) as well as poly(tetrafluoroethylene) have been reported to withstand a similar temperature without any thermal degradation and may be used safely up to similar... 

Figure 5.33 Synthesis of poly[2,5-bis(3-sulfonatopropoxy)-l,4-phenylene-alt-l,4-phenylene] (polyphenylene-ORSOa). (Reprinted with permission from Macromolecules, 17, 1975. Copyright (1994) American Chemical Society.)...

Common conductive polymers are poly acetylene, polyphenylene, poly-(phenylene sulfide), polypyrrole, and polyvinylcarba2ole (123) (see Electrically conductive polymers). A static-dissipative polymer based on a polyether copolymer has been aimounced (124). In general, electroconductive polymers have proven to be expensive and difficult to process. In most cases they are blended with another polymer to improve the processibiUty. Conductive polymers have met with limited commercial success. 

The successful development of polyfethylene terephthalate) fibres such as Dacron and Terylene stimulated extensive research into other polymers containing p-phenylene groups in the main chain. This led to not only the now well-established polycarbonates (see Chapter 20) but also to a wide range of other materials. These include the aromatic polyamides (already considered in Chapter 18), the polyphenylene ethers, the polyphenylene sulphides, the polysulphones and a range of linear aromatic polyesters. 

Several substituted linear polyphenylenes have also been prepared but none appear to have the resistance to thermal decomposition shown by the simple poly-p-phenylene. 

In 1965 the poly-(2,6-dimethyl-/7-phenylene ether) was introduced as polyphenylene oxide (misleadingly ) and also as PPO by the General Electric Co. in the USA and by AKU in Holland. The commercial materials had a molecular weight of 25 000-60 000. 

Poly(ethylene terephtlhalate) Phenol-formaldehyde Polyimide Polyisobutylene Poly(methyl methacrylate), acrylic Poly-4-methylpentene-1 Polyoxymethylene polyformaldehyde, acetal Polypropylene Polyphenylene ether Polyphenylene oxide Poly(phenylene sulphide) Poly(phenylene sulphone) Polystyrene Polysulfone Polytetrafluoroethylene Polyurethane Poly(vinyl acetate) Poly(vinyl alcohol) Poly(vinyl butyral) Poly(vinyl chloride) Poly(vinylidene chloride) Poly(vinylidene fluoride) Poly(vinyl formal) Polyvinylcarbazole Styrene Acrylonitrile Styrene butadiene rubber Styrene-butadiene-styrene Urea-formaldehyde Unsaturated polyester... 

The palladium-catalyzed formation of sulfides can generate polyphenylene sulfide from a dithiol and a dibromoarene, or from 4-bromobenzenethiol (Equation (38)).17 In 1984 Asahi Glass obtained patents for the formation of this polymer in the presence of palladium and nickel catalysts.125,126 In addition, Gingras reported palladium-catalyzed couplings of aryl halides and thiols to form discrete phenylene sulfide oligomers.127,128 A number of polyphenylene sulfide wires, ranging from dimeric to pentameric structures, were prepared by the palladium coupling, albeit in modest yields ... 

Methylene Chloride Fractionation of Cross-Coupled 1. 2 and 7. A sample of the block polymer (above 0.50g) was dissolved in 10 mL of methylene chloride. The soluton was stored at 2 C for 2 days. A polymer methylene chloride complex precipitate formed which was removed by filtration at 2aC. The precipitate was then heated at 50 to drive off the methylene chloride. The dried polymer weighed 0.43g and contained (based on IR analysis) 58% by weight of poly(phenylene oxide) and 42% by weight of polystyrene. Analysis of the filtrate after evaporation of the methylene chloride established the presence of a residue containing 17% polyphenylene oxide and 83% polystyrene. On the basis of these results, at least 72% of the initial polystyrene charged to the reaotion medium was calculated as having been incorporated into an acyl-coupled polyphenylene oxide-polystyrene block polymer. 

Fig. 1 Building units of conducting polymers, (1) polyacetylene (PA) (2) polypyrrole (PPy), polythiophene (PTh), polyfurane (PFu) (3) polyphenylene (PP) (4) polyaniline (PANI) 5 polyindole (PIND) (6) polycarbazole (PCaz) (7) polyazulene (Paz) (8) polynaphthalene (PNa) (9) polyanthracene (PAnth) (10) polypyrene (PPyr) (11) polyfluorene (PFiu) (12) poly(isothionaphthalene) (PITN) (13) poly(dithienothiophene) (14) poly(thienopyrrole) (15) poly(dithienylbenzene) (1G) poly(3-alkylthiophene) (17) poly(phenylene vinylene) (18) poly(bipyrrole) (PBPy), poly(bithiophene) (PBT) (19) poly(phenylenesulfide) (20) 4-poly(thienothiophene) (21) poly(thienyl vinylene), poly(furane vinylene) (22) poly(ethylenedioxythiophene) (PEDOT).

The first report of all-phenylene dendrimers was presented in 1990 by Miller and Neenan [10], Via a convergent approach, they coupled arylboronic acids to arylbromides under Suzuki-type conditions to synthesize the first two generations of polyphenylene dendrimers based on 1,3,5-triphenylene building units (Scheme 1). 

Table 1. Overview of the number of phenylene rings, molecular masses, and calculated sizes of different generations of unfunctionalized polyphenylene dendrimers from us and those synthesized by Miller et al. [27]...

Sulfonated poly(4-substituted benzoyl-1,4-phenylene) homopolymers and copolymers using concentrated sulfuric acid or fuming sulfuric acid have been shown to form sulfonated polymers with variable degrees of sulfonation. To improve film formation of the sulfonated polyphenylenes, multiblock copolymers have been synthesized by reacting a more flexible poly(arylene ether sulfone) with sulfonated poly-phenylenes. ... 

Nylon, polyacetal, polycarbonates, poly(2,6-dimethyl)phenylene oxide (PPO), polyimides, polyphenylene sulfide (PPS), polyphenylene sulfones, polyaryl sulfones, polyalkylene phthalates, and polyarylether ketones (PEEK) are stiff high-melting polymers which are classified as engineering plastics. The formulas for the repeating units of some of these engineering plastics are shown in Figure 1.15. 

Stiff polymers, such as polyphenylene, nylon 66, polyphenylene sulfone, and polyarylether ketone (PEEK), have relatively high Tg values because of the presence of phenylene and sulfone or carbonyl stiffening groups in the chain. 

In general, regularity in polymer structure and strong intermolecular forces favor high Tm values. Phenylene groups, such as those in polyphenylene, poly-p-phenylene oxide (PPO), and poly-p-phenylene sulfide (PPS), increase Tm values. 

Polyphenylene Oxide. This is actually poly (2,6-dimethyl-phenylene oxide) and was introduced by General Electric as the first... 

The following aspects will be addressed. (1) Conjugated polymers with benzene-derived repeat units (section II) typical examples are the already mentioned poly-/>phenylene (PPP) 6,43 polyphenylene-vinylenes (PPV) 9,43 and polyphenyleneethinylenes (PPE) 25.44 Some typical questions are obvious how do the aromatic or olefinic units interact via the formal single bonds and how far does an extra charge or an excitation delocalize over the chain. (2) Large... 

Since the thermal degradation in phenylated polyphenyls of the type XXa is caused by the loss of pendant phenyl groups, and since the reported (4, 7, 9, 10, 11, 14, 15) properties of p-polyphenylenes are quite different from those of XXa, the synthesis of an unphenylated polyphenylene by this pathway was of considerable significance. Only a few results employing this reaction have thus far been obtained. [The p-poly-phenylenes reported are black or brown, insoluble, crystalline materials of lower thermal stability than XXa.]... 

PB PBI PBMA PBO PBT(H) PBTP PC PCHMA PCTFE PDAP PDMS PE PEHD PELD PEMD PEC PEEK PEG PEI PEK PEN PEO PES PET PF PI PIB PMA PMMA PMI PMP POB POM PP PPE PPP PPPE PPQ PPS PPSU PS PSU PTFE PTMT PU PUR Poly(n.butylene) Poly(benzimidazole) Poly(n.butyl methacrylate) Poly(benzoxazole) Poly(benzthiazole) Poly(butylene glycol terephthalate) Polycarbonate Poly(cyclohexyl methacrylate) Poly(chloro-trifluoro ethylene) Poly(diallyl phthalate) Poly(dimethyl siloxane) Polyethylene High density polyethylene Low density polyethylene Medium density polyethylene Chlorinated polyethylene Poly-ether-ether ketone poly(ethylene glycol) Poly-ether-imide Poly-ether ketone Poly(ethylene-2,6-naphthalene dicarboxylate) Poly(ethylene oxide) Poly-ether sulfone Poly(ethylene terephthalate) Phenol formaldehyde resin Polyimide Polyisobutylene Poly(methyl acrylate) Poly(methyl methacrylate) Poly(methacryl imide) Poly(methylpentene) Poly(hydroxy-benzoate) Polyoxymethylene = polyacetal = polyformaldehyde Polypropylene Poly (2,6-dimethyl-l,4-phenylene ether) = Poly(phenylene oxide) Polyp araphenylene Poly(2,6-diphenyl-l,4-phenylene ether) Poly(phenyl quinoxaline) Polyphenylene sulfide, polysulfide Polyphenylene sulfone Polystyrene Polysulfone Poly(tetrafluoroethylene) Poly(tetramethylene terephthalate) Polyurethane Polyurethane rubber... 

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