Poly p- Phenyl ene

In addition to the research work presented so far, in the 1990s many other activities were directed towards the synthesis of rodlike polyelectrolytes. Some important examples will be referred to in the following. Regarding cationic polyelectrolytes in particular, Reynolds et al. described the synthesis of water-soluble PPPs such as 29 [28]. These polymers were analyzed with regard to their potential application as luminescent materials [29]. Similar polymers were reported by Swager et al. in 2000 [30]. Here, poly(p-phenyl-ene ethynylenes) 30 were investigated as active components for chemosen-sors (Scheme 7). 

Aerospace composite structures can also employ high-performance polymeric fibres such as the aramids Kevlar (DuPont) or Twaron (Teijin Twaron), poly(p-phenyl-ene-2,6-benzobisoxazole) (PBO) (Toyobo) and high-modulus polyethylene (PE) (Dynema, Certran and Spectra). Generally ultra-high-molecular-weight PE (UHMWPE) can be considered to be inert to most environments except that the service temperature is limited to <130 °C. 

Other Direct Syntheses. One route to substituted poly(p-phenyl-ene) derivatives makes use of the Bergman cyclization of enediynes (Fig. 8). Thermal treatment of the enediyne yields poly(p-phenyl-ene) derivatives with molecular weights of 1500-2500 [242]. 

V. Massardier, A. Guyot, and V. H. Tan, Direct conversion of sulfonium precursors into poly(p-phenyl-ene vinylene) by acids. Polymer 55 1561 (1994). 

J. Gmeiner, S. Karg, M. Meier, W. Riess, P. Stroh-rieg, and M. Schwoerer, Synthesis, electrical conductivity and electroluminescence of poly(p-phenyl-ene vinylene) prepared by the precursor route, Acta Polym. 44 201 (1993). 

C. Zhang, D. Braun, and A. J. Heeger, Light-emitting diodes from partially conjugated poly(p-phenyl-ene vinylene), J. Appl. Phys. 75 5177 (1993). 

C. J. Wung, M. K. P. Wijekoon, and P. N. Prasad, Characterisation of. sol-gel processed poly( p-phenyl-ene vinylene) silica and V20 composites using waveguide Raman, Raman and FTIR spectroscopy. Polymer 34 14 (1993). 

The discovery of highly conducting poly acetylene in 1977 [1] prompted the synthesis of other polymers with conjugated 7r-systems such as polypyrrole [2], poly-p-phenyl-ene [3], poly-p-phenylenevinylene [4], polyphenylenesulflde [5, 6], polyaniline [7], as well as of other poly heterocycles such as polythiophene [8], polyfuran [8], poly-selenophene [9], or more extended polyaromatics such as polyazulene [10]. Because they can have a variety of structural variations, polythiophenes have become the type of conducting polymer most frequently investigated because conductivity is mostly unaffected by substituents [11]. In addition, both conducting and semiconducting polythiophenes are very stable and readily characterized. 

The preparation of networks from wormlike polymers such as polyesters and polyamides, and from stiifer polymers such as polyimides and poly-p-phenyl-enes, will be described in Sect. 3 below. In addition to the chemical nature of the stiff segments, attention will be paid to the rigidity or flexibility of the junction points, and to the sequence of reactions performed in order to obtain various rigid aromatic networks. 

Poly(9,9 -dihexylfluorene-2,7-divinylene-m-phenylene vinylene-stat-p-phenyl-ene vinylene), 30, 31, 51 Poly(2,5-dimethoxy-l,4-phenylene vinylene), 95 Poly(2-(A, A -dimethylamino) phenylene vinylene), 100 Poly(2-dimethyloctylsilyl)-phenylene vinylene, 99 Poly(9,9-dioctylfluorene), 31, 110 Poly(9,9-dioctylfluorene-co-lluorenone), 30 Poly(4,4 -diphenyl ether-l,3,4-oxadiazole), 334 Poly(2,6-diphenyl-l,4-phenylene oxide), 152 Poly(2,6-diphenyl-l-4-phenylene oxide), 141 Poly(dithiathianthrene), 189 Poly(2-dodecyl-p-phenylene), 36 Poly(AT-epoxypropyl)carbazole, 13 Poly(ether ether ketone), 209 Poly(ether imide), 154, 214, 264, 376 Pol(yether ketone), 213 Poly(ether nitrile), 227 Poly(ethersulfone), 209, 264... 

Leising, U. Scherf, K. Mullen, Photophysics of Methyl-Substituted Poly(para-Phenyl-ene)-1ype Ladder Polymers, in G. Hadziio-annou, P.F. van Hutten (eds ), Semiconducting Polymers, Wiley-VCH, Weinheim (2000), p. 235. 

A. M. Kraft, and A. B. Holmes, The fabrication and assessment of optical waveguides in poly(p-phenyl-enevinylene) poly(2,5-dimethoxy-p-phenylenevinyl-ene) copolymer, Synth. Met. 55-57 3683 (1993). 

Ninivin, C.L., BaUand-Longeau, A., Demattei, D., Palmas, P., Saillard, J., Coutanceau, C., Leger, J.M. (2006) Determination of the physicochemical characteristics and electrical performance of postsulfonated and grafted sulfonated derivatives of poly(para-phenyl-ene) as new proton-conducting membranes for direct methanol fuel cell. Journal of Applied Polymer Science, 101, 944—952. 

For another poly-p-phenylene system it is reported that aggregation to defined cylindrical micelles occurs in aqueous solution [15, 16]. In these systems the ionic groups (sulfonate groups) are directly attached to the phenyl-ene units. Moreover, long n-alkyl side chains are attached to the PPP backbone. The polyelectrolytes PPP-1 considered here have the trialkyl ammonium groups linked to the backbone via a hexamethylene spacer. It is obvious that the spatial requirement of these substituents prevents the macromolecules from forming such aggregates. 

H. M. Colquhoun, D. F. Lewis, P. Hodge, A. Ben-Haida, D. J. Williams, and I. Baxter. Ring-chain interconversion in high-performance polymer systems. 1. [poly(oxy-4,4 -biphenyleneoxy-1,4-phenylenesulfony 1-1,4-phenyl-ene)] (Radel-R). Macromolecules, 35 6875-6882, 2002. 

It must be noted that the values reported in the literature vary over broad ranges. Therefore, the values listed here reflect only the general behavior of several classes of compounds. It can be seen in Table 3.5 that trans-polyacetylenes (PAs) and polydiacetylenes (PDAs) exhibit the largest third-order NLO susceptibilities. The x value of cis-PA (not shown) is more than an order of magnitude smaller than that of trans-PA. Derivatives of poly-p-phenylene, poly(phenyl-ene vinylene), and polythiophene also exhibit NLO activity, but to a much lesser extent than PAs and PDAs. As pointed out above, polysilanes also possess quite large x values. This is explained by the cr-conjugation of the silicon chain, which implies a pronounced delocalization of cr-electrons. A very large x value... 

The chemical structures of sulfonated poly(4-phenoxybenzoyl-l,4-phenyl-ene) (S-PPBP) (1), poly(p-xylylene) (S-PPX) (2), poly(phenylene sulfide) (S-PPS) (3), poly(phenylene oxide) (S-PPO) (4), poly(ether ether ketone) (S-PEEK) (5), poly(ether ether sulfone) (S-PEES) (6), arylsulfonated poly(ben-zimidazole) (S-PBl) (7) sulfonated polyphenylquinoxiiline (S-PPQ) (8) and sulfonated phenoxy polyperyleneimide (PSPPI) (9) are shown below. ACPs are sulfonated using common sulfonating agents [82-85]. In particular, PEEK can be sulfonated in concentrated sulfuric acid [50], chlorosulfonic acid [86], SO3 (either pure or as a mixture) [53,65,86,87], a mixture of methanesulfonic acid with concentrated sulfuric acid [88] and acetyl sulfate [89,90]. 

White light emission was obtained from a device made of a ternary polymer blend, comprised of PVK, poly(9,9 -dihexylfluorene-2,7-divinylene-m-phenyl-ene vinylene-stat-p-phenylenevinylene) (CPDHFPV). 

Dencheva N, Denchev Z, Oliveira M J and Funari S S (2010) Microstructure studies of in situ composites based on polyethylene/polyamide 12 blends, Macromolecules 43 4715-4726. Polaskova M, Cermak R, Sedlacek T, Kalus J, Obadal M and Saha P (2010) Extrusion of polyethylene/poljTDropylene blends with microfibrillar-phase morphology, Polym Compos S1 1427-1433. Wang H, Guo J and He Y X (2011) Rheology and thermal properties of polypropylene/poly(phenyl-ene sulfide) microfibrillar composites, Adv Mater Res 194-196 1506-1509. 

In three mainly synthetic works Godt et al. and Mullen et al. reported on rod-coil systems having poly(para-phenyleneethynylene) or poly(p rfl-phenyl-ene) as the rod part. Miillen et al. [105] showed the synthesis of poly(para-phenyleneethynylene)-block-poly(ethyleneoxide) by condensation of monofunc-tionalized homopolymer blocks. Godt et al. [106] reported on the synthesis of poly(para-phenyleneethynylene)-block-polyisoprene and the transformation of such rod-coils into corresponding coil-rod-coil triblock copolymers. The synthesis of poly(para-phenylene) as the rod part and polystyrene or poly(ethyl-eneoxide) as the coil part by condensation of prepolymers was also reported by Mullen et al. [107],... 

Figure 28.3 Molecular structures of siloxane hybrid precursors. DCM= 4-dicyanomethy-lene-2-methyl-6-[p-(dimethylamino)styryl]-4/-/-pyran PBD= 2-(4-biphenylyl)-5-(4-ferf-butyl-phenyl)-1,3,4-oxadiazole NABUP= A/-(4-butyl-phenyl)-4-[(A/-2-hydroxyethyl)(methyl)amino] naphthalimide TPPy = 1,3,6,8-tetraphenylpyr-ene PHEMA= poly(2-hydroxyethyl...

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