Polymer Polyacrylonitrile

This family includes a range of polyacrylates (III), polymethacrylates (IV) and the important fibre-forming polymer, polyacrylonitrile (V). 

Synonyms and trade names cyanoethylene, 2-propenenitrile, vinyl cyanide Use and exposure Acrylonitrile is a colorless, man-made liquid with a sharp, onion- or garlic-like odor. It can be dissolved in water and evaporates quickly. Acrylonitrile is used principally as a monomer in the manufacture of synthetic polymers, polyacrylonitriles, acrylic fibers, and other chemicals such as plastics and synthetic rubber. A mixture of acrylonitrile and carbon tetrachloride was used as a pesticide in the past. - Acrylonitrile is highly flammable and toxic. It undergoes explosive polymerization. The... 

Polylactic acid (PLA), the structure of which is shown in Figure 7.10, is a polyester fibre in which there has been recent interest because of its environmental credentials. PLA may be derived from renewable resources, such as cornstarch, and it is biodegradable. PLA may be coloured using certain disperse dyes, although the dyes do not exhaust as well as on PET, mainly because of its aliphatic character. Acrylic fibres are synthetic fibres based essentially on the addition polymer polyacrylonitrile, the essential structure of which is illustrated in Figure 7.11. However, most acrylic fibres are rather more complex and contain within their structure anionic groups, most commonly sulfonate (-SOs ), but also carboxylate (-CO2 ) groups either as a result of the incorporation of co-polymerised monomers in... 

The values of t (i.e., the critical exponent for electrical conductivity versus fluence), obtained from the slope of logftr) versus log(4> - j) linear dependences for various ion-implanted polymers (polyacrylonitrile [11], polyimide [87], poly-2,6-dimethyl-polyphenyleneoxide [11], perylene derivatives [12]), are 4-5 when the energy is deposited predominantly by the collisional mechanism and 7-8 when electronic stopping prevails. These values of the critical exponent for conductivity are substantially higher than those observed for metal nanoparticles in a dielectric matrix [88], which can be apparently explained by the effects of the conducting phase ordering during the implantation. 

POLYACRYLATES. See Acrylic Ester Polymers. POLYACRYLONITRILE. See Acrylonitrile Polymers. POLYAMIDES, AROMATIC. See Volume 3. 

Polyacrylonitrile. The polymer polyacrylonitrile (PAN) isusedmostly for the production of carbon fibers. 

This polymer, polyacrylonitrile (PAN), can be processed into a valuable fibre. The best high modulus carbon fibres are produced from the pyrolysis of PAN. The copolymer of acrylonitrile and styrene is a random linear molecule consisting of styrene units and acrylonitrile units the structure is... 

The preparation of macromolecular crystals from solution has been reported for a variety of polymers most of this work up to 1970 has been summarized by Wunderlich. The list given therein includes many (tactic) hydrocarbon polymers, polyacrylonitrile, polyacrylic acid, polyvinyl alcohol, linear polyethers, polyesters and polyamides, a trans-1,4-diene, and cellulose. 

The importance of some of these process issues relating to polymer solution rheology and solidification can be seen in the dry spinning of acrylics (Cox, 2005). An acrylic fiber is one in which the fiber-forming substance is any long chain synthetic polymer composed of at least 85% by weight of acrylonitrile (AN) units (-CH2-CH(CN)-). Acrylic fibers are made from the polymer polyacrylonitrile (PAN), a synthetic, semicrystalline, organic polymer... 

Acrylic Polymers Polyacrylonitrile was the first synthetic polymer used to prepare HD membranes. PAN used for preparing HD and 1 IF membranes is a copolymer consisting of a mixture (about 85 15 by mole) of an acrylic and an acrylonitrile monomer and a copolymer that is either methallylsulfonate or methylmethacrylate. PAN membranes may exhibit a symmetric homogeneous (e.g., the Hospal AN69 membrane) or an asymmetric (e.g., the Asahi PAN membrane) wall structure. All feature high Lp and are used in high-flux HD, HDF, and HF. Today, PAN membranes are commercially... 

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