PAN—See Polyacrylonitrile

Paniplex CK. See Calcium stearoyl lactylate Paniplex SK. See Sodium stearoyl lactylate Panodan 235] Panodan FDPKosher, Panodan FDP] Panodan SD. See Diacetyl tartaric acid esters of mono- and diglycerides Panol . See Papain Pano-ram. SeeFenfuram PAN resin. See Polyacrylonitrile Pansy. See Pansy (Viola tricolor)... 

The first reported synthesis of acrylonitrile [107-13-1] (qv) and polyacrylonitrile [25014-41-9] (PAN) was in 1894. The polymer received Htde attention for a number of years, until shortly before World War II, because there were no known solvents and the polymer decomposes before reaching its melting point. The first breakthrough in developing solvents for PAN occurred at I. G. Farbenindustrie where fibers made from the polymer were dissolved in aqueous solutions of quaternary ammonium compounds, such as ben2ylpyridinium chloride, or of metal salts, such as lithium bromide, sodium thiocyanate, and aluminum perchlorate. Early interest in acrylonitrile polymers (qv), however, was based primarily on its use in synthetic mbber (see Elastomers, synthetic). 

PAN-based carbon fiber processing flow chart, 26 731. See also Polyacrylonitrile (PAN)... 

Cyclization is a key reaction in the production of carbon fibers from polyacrylonitrile (PAN) (acrylic fiber see Sec. 3-14d-2). The acrylic fiber used for this purpose usually contains no more than 0.5-5% comonomer (usually methyl acrylate or methacrylate or methacrylic acid). Highly drawn (oriented) fibers are subjected to successive thermal treatments—initially 200-300°C in air followed by 1200-2000°C in nitrogen [Riggs, 1985]. PAN undergoes cyclization via polymerization through the nitrile groups to form a ladder structure (XXVII). Further reaction results in aromatization to the polyquinizarine structure (XXVIII)... 

Carbon fibres are made by carbonizing or pyrolyzing polymer fibres. I came across the chemical aspects of this process in the book Principles of Polymerization by G. Odian in which the author describes how these fibres are made of polyacrylonitrile (PAN) a polymer which is represented in figure 14.4 (see also chapter 3). 

Polymerization in miniemulsion is a very suitable technique to avoid this problem since each droplet acts as a nanoreactor. As a result, pure polyacrylonitrile (PAN) nanoparticles were obtained in the size range 100 nmwater phase. This is no restriction for a miniemulsion polymerization process, and the use of a hydro-phobic initiator 2,2 azobis(2-methylbutyronitrile) allows the preservation of the droplets as the reaction sites by droplet nucleation (see Fig. 12). Initiation of the... 

The first high-strength carbon fibres were produced in the 1950s (see Donnet and Bansal, 1984). The early carbonized products were rayon-based, but it was soon found that the mechanical properties and the carbon yield could be improved by the use of polyacrylonitrile (PAN) as the precursor. Also, less expensive fibres of somewhat lower strength and modulus could be made from various other precursors including petroleum pitch and lignin. However, cotton and other forms of natural cellulose fibres possess discontinuous filaments and the resulting mechanical properties were consequently found to be inferior to those of the rayon-based fibres. 

Pyrolysis of the intrachaimel polyacrylonitrile led to the expected loss of nitrogen, similar to observations in bulk and thin film experiments. As in the case of polyaniline in MCM-41 (see above), nitrogen sorption isotherms showed reduced pore volumes for the inclusion compounds, demonstrating the formation of PAN and carbonized material in the chaimels of the host. 

Cellulose di- and triacetate fibres (CA, CT) as well as acrylic fibres (polyacrylonitrile, PAN) are all soluble in the zinc chloride-iodine reagent. An initial differentiation is made using the acetone test on a watchglass only CA and CT fibres dissolve (evidenced by a cloudy evaporation residue). Differentiation between CA and CT fibres CA dissolves in Frott6 II reagent (see Table 8.1), CT only swells. Results are similar in zinc chloride/formic acid, but with a less distinct difference (CT swells more markedly). PAN fibres dissolve in cold concentrated nitric acid and in dimethylformamide at 100 °C. They swell in boiling 85 % formic acid and decompose at about 280 °C without melting. 

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