Polyacrylonitrile produced

In the latter case, a free radical may be created by the interaction of the initiator with Polyacrylonitrile producing a free radical on the backbone of the polyacylonitrile as under ... 

The combustion of polyacrylonitrile produces hydrogen cyanide. Any of the chlorine-containing polymers will produce hydrogen chloride upon combustion. This would include polyvinyl chloride and polyvinylidene chloride. 

Carbon fibers from different sources complement each other in their properties. Ktch fibers usually display higher density, higher elasticity and higher electrical conductivity, while polyacrylonitrile produces exceptionally high strength fibers. 

The way in which these factors operate to produce Type III isotherms is best appreciated by reference to actual examples. Perhaps the most straightforward case is given by organic high polymers (e.g. polytetra-fluoroethylene, polyethylene, polymethylmethacrylate or polyacrylonitrile) which give rise to well defined Type III isotherms with water or with alkanes, in consequence of the weak dispersion interactions (Fig. S.2). In some cases the isotherms have been measured at several temperatures so that (f could be calculated in Fig. 5.2(c) the value is initially somewhat below the molar enthalpy of condensation and rises to qi as adsorption proceeds. In Fig. 5.2(d) the higher initial values of q" are ascribed to surface heterogeneity. 

Tetraethylene glycol may be used direcdy as a plasticizer or modified by esterification with fatty acids to produce plasticizers (qv). Tetraethylene glycol is used directly to plasticize separation membranes, such as siHcone mbber, poly(vinyl acetate), and ceUulose triacetate. Ceramic materials utilize tetraethylene glycol as plasticizing agents in resistant refractory plastics and molded ceramics. It is also employed to improve the physical properties of cyanoacrylate and polyacrylonitrile adhesives, and is chemically modified to form polyisocyanate, polymethacrylate, and to contain siHcone compounds used for adhesives. 

Azacarbocyanines. A cyanine containing three carbon atoms between heterocychc nuclei is called a carbocyanine (n = 1 in (46)). Replacing these carbon atoms by one, two, and three nitrogen atoms produces azacarbocyanines, diazacarbocyanines, and triazacarbocyanines, respectively. Dyes of these three classes are important yellow dyes for polyacrylonitrile, eg. Cl Basic Yellow 28 [52757-89-8J (Cl 48054) (47). 

Because of their unique blend of properties, composites reinforced with high performance carbon fibers find use in many structural applications. However, it is possible to produce carbon fibers with very different properties, depending on the precursor used and processing conditions employed. Commercially, continuous high performance carbon fibers currently are formed from two precursor fibers, polyacrylonitrile (PAN) and mesophase pitch. The PAN-based carbon fiber dominates the ultra-high strength, high temperature fiber market (and represents about 90% of the total carbon fiber production), while the mesophase pitch fibers can achieve stiffnesses and thermal conductivities unsurpassed by any other continuous fiber. This chapter compares the processes, structures, and properties of these two classes of fibers. 

On the other hand, organic materials of relatively low molecular weight such as acetylene, benzene, ethylene and methane, can produce vapour-grown carbon materials by imperfect combustion or by exposing their vapour to a heated substrate in an electric furnace in the presence of a metal catalyst. The latter process generates VGCFs. Other precursors to VGCF include polyacrylonitrile (PAN), isotropic or mesophase pitch, rayon or nylon [8]. 

The commercial fibers are produced from rayon, polyacrylonitrile, and petroleum pitch. When acrylonitrile is heated in air at moderate temperatures (= 220°C ), HCN is lost, and a ladder polymer is thought to be the intermediate ... 

Recently, nitrilases have been applied to polymer modification, specifically to the modification of polyacrylonitrile (PAN). Nearly 3 x 106 tons of PAN are produced per annum and used in the textile industry. However, there is a great need to improve moisture uptake, dyeability with ionic dyes, and feel of this acrylic fiber. The cyano moieties of PAN have been successfully modified to carboxylates with the commercial Cyanovacta nitrilase, thus enhancing the aforementioned properties of PAN [98]. Nitrilase action on the acrylic fabric was improved... 

Exposed to HCN gas produced from combustion of polyacrylonitrile materials at various temperatures... 

The created technology of producing cationic and anionic exchange fibroid sorbents on the base of polyacrylonitrilic fibers is described in the paper. Chemical characteristics of the sorbent and filters were investigated. The static exchange capacity is 3-4 meq/g for cationic sorbents and 1-2 meq/g for anionic sorbents. The removal coefficient of listed radionuclides from drinking water by the filter is 102 - 103. 

The produced cationic and anionic exchange fibroid sorbents on the base of polyacrylonitrilic fiber were used to produce household water filters. The cloths of cationic and anionic exchange sorbents with mass of 50 g each one were reeled on a perforated cylinder with diameter of 10 mm and length of 15 mm. This cartridge could be easily replaced. Initial tap water... 

An atactic polymer can crystallize, for instance the case of polyacrylonitrile, whose crystallizability has been explained on the basis of local conformations, which produce extended and straight chains.140... 

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. 

---