Pyrolyzed polyacrylonitrile

Polydithiazoles Polyoxadiazoles Polyamidines Pyrolyzed polyacrylonitrile Polyvinyl isocyanate ladder polymer Polyamide-imide Polysulfone Decompose at 525°C (977°F) soluble in concentrated sulfuric acid. Decompose at 450-500°C (842-932°F) can be made into fiber or film. Stable to oxidation up to 500°C (932°F) can make flexible elastomer. Stable above 900°C (1625°F) fiber resists abrasion with low tenacity. Soluble polymer that decomposes at 385°C (725°F) prepolymer melts above 405° C (76l.°F). Service temperatures up to 288° C (550°F) amenable to fabrication. Thermoplastic use temperature —102°C (—152°F) to greater than 150° C (302°F) acid and base resistant. 

Pyrolyzed polyacrylonitrile Stable above 900°C (1,625°F) fiber resists abrasion with low tenacity. 

Two nitrogen-containing polymeric materials with extended aromatic ladder structures have been chosen for direct fluorination studies (Figure 14.9).57 Pyrolyzed polyacrylonitrile (3) and paracyanogen (4) [poly(pyrazinopryazine)] have been subjected to direct fluorination to produce perfluorinated analogues. 

Fig. 15.8 Redox-active polymers for heterogeneous dehydrogenation catalysis, (a) trimerized phenanthrene quinone [42], (b) benzoquinone biphenyl copolymer [41], (c) polynaphthoquinone [40], (d) polyaniline [43], (e) pyrolyzed polyacrylonitrile [44].

The use of pyrolyzed polyacrylonitrile (PPAN) and polyaniline (PAni) (Fig. 15.8(d), (e)) as catalysts for the ODH of ethylbenzene should only be mentioned here for the sake of completeness. Although first results were quite promising [45], this concept has so far not been followed in terms of N-doped nanocarbon catalyst development. This is most likely due to the poor self-oxidation resistance as a result of polar C-N bonds. 

Carbon fibers have been used as filaments for lamps for nearly a century, since Edison first used them. In the early 1960s, Shindo developed the first modern carbon fiber when he pyrolyzed polyacrylonitrile (PAN) fibers [5]. 

Manassen, J., Wallach, J. Organic Polymers. Correlation between their Structure and Catalytic Activity in Heterogeneous Systems. I. Pyrolyzed Polyacrylonitrile and Poly-cyanoacetylene. J. Am. Chem. Soc. 87, 2671 (1965). 

However, it is also possible to cycle CM made from pyrolyzed polyacrylonitrile in aqueous electrolytes, according to Beck and Zahedi [378]. Figure 30 shows relatively flat redox peaks around the quinone/hydroquinone center (f/s — 0 V, about 0.7 V vs. SHE). Protons are the counterions in this case. A polyquinonimine structure is concluded from (electro)chemical and FTIR data (cf. Fig. 34). These acceptor-type compounds have relatively high specific capacities of about 300 Ah/kg in the steady state. The initial capacities are even higher. It should be mentioned that graphite nanotubules were synthesized in the nanopores of a porous AI2O3 matrix at 250/ 600 °C [433]. 

Metz, P. D. Teoh, H. VanderHart, D. Structural, Electrical and Optical Properties of Pyrolyzed Polyacrylonitrile, (In preparation). 

Ohms, D., S. Herzog, R. Franke, V. Neumann, K. Wiesener, S. Gamburcev, A. Kai-sheva, and I. Iliev (1992). Influence of metal ions on the electrocatalytic oxygen reduction of carbon materials prepared from pyrolyzed polyacrylonitrile. J. Power Sources 38, 327-334. 

Gouerec P, Miousse D, Tran-Van F, Dao LH (1999) Characterization of pyrolyzed polyacrylonitrile aerogel thin films used in double-layer supercapacitors. J New Mater Electrochem Syst 2 221-226 Woignier T, Reynes J, Phahppou J, Dussossoy JL, Jacquet-Francillon N (1998) Sintered sUica aerogel a host matrix for long life nuclear wastes. J Non-Cryst Solids 225 353-357... 

Thakur M, Pemites RB, Nitta N, Isaacson M, Sinsabaugh SL, Wong MS, Biswal SL (2012) Freestanding macroporous silicon and pyrolyzed polyacrylonitrile as a composite anode for lithium ion batteries. Chem Mat 24 2998-3003... 

Some applications require cheap electroconductive material based on small silicon particulates of high surface area. Authors of paper (Thakur et al. 2012) report on ultrasonically fiuctured macroporous membranes, mixing silicon particulates (size range 10-50 pm) with pyrolyzed polyacrylonitrile and application of the mixture for produeing long life anodes of lithium ion batteries. 

Studart AR, Gonzenbach UT, Tervoort E, Gauckler LJ (2006) Processing routes to macroporous ceramics a review. J Am Ceram Soc 89(6) 1771-1789 Thakur M, Sinsabaugh SL, Isaacson MJ, Wong MS, Biswal SL (2012) Inexpensive method for producing macroporous silicon particulates with pyrolyzed polyacrylonitrile for lithium ion... 

Pyrolyzed polyacrylonitrile Polyvinyl isocyanate ladder polymer... 

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