Acrylic acid Carbon fibers

Itaconic acid is a specialty monomer that affords performance advantages to certain polymeric coatings (qv) (see Polyesters, unsaturated). Emulsion stabihty, flow properties of the formulated coating, and adhesion to substrates are improved by the acid. Acrylonitrile fibers with low levels of the acid comonomer exhibit improved dye receptivity which allows mote efficient dyeing to deeper shades (see Acrylonitrile polymers Fibers, acrylic) (10,11). Itaconic acid has also been incorporated in PAN precursors of carbon and graphite fibers (qv) and into ethylene ionomers (qv) (12). 

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)... 

Around the same time, Mansmann and coworkers reported the production of carbon fibers from a variety of dry-spun materials, including lignin (lignosulfonates) by the simple addition of small amounts of PEO or acrylic acid-acrylamide copolymers. Although similar to the procedure of Ohtani, Mansmann employed acidic rather than neutral and/or alkaline spinning conditions. 

Ethylene has been separated from ethane by a silver nitrate solution passing countercurrent in a hollow fiber poly-sulfone.165 This separation has also been performed with the silver nitrate solution between two sheets of a polysilox-ane.166 A hydrated silver ion-exchanged Nafion film separated 1,5-hexadiene from 1-hexene with separation factors of 50-80.167 Polyethylene, graft-polymerized with acrylic acid, then converted to its silver salt, favored isobutylene over isobutane by a factor of 10. Olefins, such as ethylene, can be separated from paraffins by electroinduced facilitated transport using a Nafion membrane containing copper ions and platinum.168 A carbon molecular sieve made by pyrolysis of a polyimide, followed by enlargement of the pores with water at 400 C selected propylene over propane with an a-valve greater than 100 at 35°C.169... 

Aminopropylmorpholine Dimethyl terephthalate Ethylene 2-(5-Ethyl-2-pyridyl)ethyl acrylate Potassium bromide fiber mfg., polyester Diisopropylamine fiber mfg., rayon stable Carbon disulfide fiber mfg., self-extinguishing Benzene phosphinic acid fiber mfg., synthetic Caprolactam... 

Numerous nylon blends prepared by compatibilization or reactive blending are commercially successful. The modifiers fiequenfly utilized in commercial nylon blends include polyolefin, thermoplastic polyolefin, thermoplastic polyunethane, ionomer, elastomer, ethylene-propylene rubber, nitrile mbber, polyftetrafluoroethylene), poly (phenylene ether), poly(ether amide), silicone, glass fiber, and carbon fiber. The nonpolar modifiers such as polyolefin, maleic anhydride or a polar vinyl monomer such as acrylic acid, methaciylic acid and fimiaric acid is fiequently incorporated to introduce reactive sites in nylon. 

The rate controlling step in the production of carbon fiber from an acrylic precursor is the oxidation stage and G Gould and his research team looked at ways of speeding up this reaction. Various techniques could be used to catalyze the cyclization of PAN, but because the SAF already contained a catalyst comonomer (itaconic acid), the effects were much smaller than those reported in the literature for other acrylic fibers. One of the most promising was treatment with a Lewis acid, SnCU, which when applied as a solution in diphenyl ether, reduced the residual exotherm of SAF to less than 50 cal in only 6 min, which would normally have taken some 3 h of air oxidation at 220°C to have produced the... 

Amide comonomers have a less pronounced effect than acid comonomers. Acrylate comonomers do not initiate the cyclization reaction [78,79], whilst MMA results in a lower carbon yield than MA. The bulky side groups of an ester comonomer lower the crystallinity and crystal size but improve the segmental mobility of the polymer chains [22,23]. The size of the ester molecule also affects the structural parameters of the precursor and the resultant carbon fibers have a lower average orientation and mechanical properties [21]. 

Carbon nanofibers derived from electrospun PAN are long (centimeter long nanofibers are fabricated routinely), continuous and relatively well aligned, hence they are ideal for strengthening, stiffening and toughening of polymers [10]. PAN homopolymer has been hardly used because of its poor properties and processability, so the monomers such as acrylic acid (AA), methacrylic acid (MAA) and methylmethacrylate (MMA) have been widely added to PAN monomer to form high performance carbon fibers [11]. 

Most textile acrylics contain 10-15% comonomers. For carbon fiber precursors lower comonomer levels are used (about 5%) comonomers are selected that promote the reactions in the aftertreatment (methyl acrylate, itaconic acid). Wet spinning is preferred because the cross-section can be controlled better then. In dry spinning skin formation can hardly be prevented and eventually the cross-section collapses into a "dog bone shape, which is not desirable in carbon fiber applications. Precursor filaments are drawn to much higher draw ratios (> lOx) than tex-... 

HP is chemically a three-carbon, optically inactive, specialty chemical with commercial interest. It is the structural isomer of lactic acid (Kxunar et al., 2013). It can be used as an intermediate for the synthesis of other important chemicals, such as malonic acid, 1,3-propanediol (PDO), acrylonitrile, acrylic acid, and acrylamide. These compounds are used for making adhesives, polymers, fibers, plastic packing, resins, and cleaning agents, as listed in Fig. 6.1.3-HP acts as a starting material for the synthesis and production of poly-3-hydroxy... 

Acetylene works Acrylates works Aldehyde works Aluminum works Amines works Ammonia works Anhydride works Arsenic works Asbestos works Benzene works Beryllium works Bisulfate works Bromine works Cadmium works Carbon disulfide works Carbonyl works Caustic soda works Cement works Ceramic works Chemical fertilizer works Chlorine works Chromium works Copper works Di-isocyanate works Electricity works Fiber works Fluorine works Gas liquor works Gas and coke works Hydrochloric acid works Hydrofluoric acid works Hydrogen cyanide works Incineration works Iron works and steel works... 

Benzotrichloride Method. The central carbon atom of the dye is supplied by the trichloromethyl group fromy>-chlorobenzotrichloride. Both symmetrical and unsymmetrical triphenylmethane dyes suitable for acrylic fibers are prepared by this method. 4-Chlorobenzotrichloride is condensed with excess chlorobenzene in the presence of a Lewis acid such as aluminium chloride to produce the intermediate aluminium chloride complex of 4,4, 4"-trichlorotriphenylmethyl chloride (18). Stepwise nucleophilic substitution of the chlorine atoms of this intermediate is achieved by successive reactions with different a.rylamines to give both symmetrical (51) and unsymmetrical dyes (52), eg, N-(2-chlorophenyl)-4-[(4-chlorophenyl) [4-[(3-methylphenyl)imino]-2,5-cyclohexadien-l-yhdene]methyl]benzenaminemonohydrochloride [85356-86-1] (19) from / -toluidine and a-chloroaniline. 

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