Polyacetylenes furane

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).

A battery cell where both the electrodes consist of dopable polymer is shown in Figure 5.23. The electrolyte in this case consists of Li+ClO 4 dissolved in an inert organic solvent, usually tetrahydro-furan or propylene carbonate. When two sheets of polyacetylene or PPP are separated by an insulating film of polycarbonate saturated in an electrolyte (lithium perchlorate), and completely encapsulated in a plastic casing, a plastic battery can be made. The two sheets of polyacetylene or PPP act as both anode and cathode for the battery. A schematic is shown in Figure 5.24. Although doped polyacetylene and polyaniline electrodes have been developed, polypyrrole-salt films are the most promising for practical appKcation. 

Polyynes (polyacetylenes). Compounds with very diverse structures containing several C/C triple bonds are produced mainly by fungi (basidiomycete cultures) and plants of the families Asteraceae, Apiaceae, and Araliaceae. In addition to conjugated triple bonds the R often also contain C/C double bonds, allene units, thiophene and furan rings. On account of the close biosynthetic relationships between these compounds, the term R is used as a collective name even when only one C/C triple bond is present in the molecule. As result of the work of Bohimann, E. R. H. Jones, Sorensen, and others more than one thousand natural R are now known. The antibiotically active mycotnycin (C H, g02, Mr 198.22, mp. 75 °C) from basidiomycete cultures, dehydromatricaria ester (CiiHgO, Mr 172.18, mp. 105-106°C) from Asteraceae, and the thiarubrins may be mentioned as typical examples (see also ter-thienyls). 

Polyheterocycles. Heterocychc monomers constitute a third class of monomers that can he polymerized to form fully conjugated polymers the most common of these monomers, shown in equation 7, are p5urole (X = NH), thiophene (X = S), and furan (X = O). They can he doped to give electrical conductivity when pol5unerization occurs in the 2,5-positions. These monomers can be polymerized both by electrochemical and chemical methods. The polyheterocycles have received considerable attention for their electron-rich nature, which leads to materials that are easily oxidized and therefore more stable in the oxidized state. Additionally, the increased structural complexity of polyheterocycles relative to polyacetylenes makes structural modifications possible for improved processability. 

For completeness, after discussing the histories of carbon fibers derived from cellulose, PAN, and pitch, the category of "other precursors" should be covered. The tremendous activity in carbon fiber research and development is reflected in the large number of precursors which have been converted into carbon fibers. Besides the "big three", the list [34] includes phenolic polymers, phenol formaldehyde resin, furan resins [35], polyacenaphthalene, polyacrylether, polyamide, polyphenylene, polyacetylene, polyimide, polybenzimidazole, polybenzimidazonium salt, polytriazoles, modified... 

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