Acrylic acid fiber preparation

Acrylamide with a demand of 200,000 tons year" is one of the most important commodities in the world. It is used for the preparation of coagulators, soil conditioners, stock additives for paper treatment, and in leather and textile industry as a component of synthetic fibers. Conventional chemical synthesis involving hydration of acrylonitrile with the use of copper salts as a catalyst has some disadvantages rate of acrylic acid formation higher than acrylamide, by-products formation and polymerization, and high-energy inputs. To overcome these limits since 1985, the Japanese company Nitto Chemical Industry developed a biocatalyzed process to synthesize... 

Into a pressure pol5nnerization vessel are added 150 gm water, 3 gm ammonium persulfate, and 24 gm (0.415 mole) allyl alcohol. The mixture is cooled to 15°C and then 50 gm (0.695 mole) of acrylic acid is added. The mixture is further cooled to - 20°C and 26 gm (0.406 mole) of sulfuric dioxide is added. The vessel is sealed and polymerization is initiated by raising the temperature to 40°C with initial agitation. Polymerization is continued for 16 hr and then the reaction mixture is cooled, water added, and the mixture steam distilled at 200 mm pressure. The steam distillation is continued until 100 gm water is collected. The polymer is soluble in hot water and when the solution is cooled no polymer settles. The solution has little odor and can be used to cast clear film on glass plates, or used as spinning dope to prepare fibers which are insolubi-lized by heat. The polymer analyzes as follows 27% sulfur dioxide, 50% acrylic acid, and 23% allyl alcohol. 

The properties of acrylic ester polymers depend largely on the type of alcohol from which the acrylic acid ester is prepared [26]. Solubility in oils and hydrocarbons increases as the length of the side chain increases. The lowest member of the series, poly(methyl acrylate), has poor low-temperature properties and is water sensitive. It is therefore restricted to such applications as textile sizes and leather finishes. Poly(ethyl acrylate) is used in fiber modifications and in coatings and poly(butyl acrylate) and poly(2-ethylhexyl acrylate) are used in the formulation of paints and adhesives. 

Lyocell tibers have been explored in blends. Chang et al. [141] prepared Lyocell based blends. Poly(vinyl alcohol) (PVA), poly(vinyl alcohol-co-ethylene) (EVOH), and poly(acrylic acid-co-maleic acid) (PAM) were used as fillers in blends with lyocell produced through solution blending. The results showed that blends with PVA exhibit the best tensile properties. Thus, Lyocell fibers have recently been used as reinforcement for thermoplastic fiber composites. 

Polyacrylonitrile (PAN) has been used in the preparation of UP membranes for a long time [82, 83] due to its superior resistance to hydrolysis and oxidation. PAN is highly crystalline and relatively hydrophilic and is usually copolymerized with more hydrophilic monomers to improve processability and to make it less brittle. Hollow fibers can be prepared from PAN dissolved in nitric acid [84]. Preparation of PAN membranes by phase inversion from solutions in DMAC, DMF or NMP is also possible. An example is shown in Fig. 4.4. A Sumitomo patent [85] discloses the preparation of membranes from copolymers containing 89% acrylonitrile and 11% ethyl acrylate dissolved in DMF and formamide and coagulated in water. A microporous membrane is obtained. In order to make the membranes suitable for reverse osmosis, they were submitted to a plasma treatment in the presence of 4-vinyl pyridine. 

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. 

Moreover, long(>200 cm) fibers 1 mm in diameter were formed from thermoplastic gels ofY-123 ceramics and PVA." Calcined fibers exhibited values of = 92-94K. These fibers form materials characterized by different values, depending on the degree of saponification (DS) and the Y-123 ceramic content of these materi-als." The minimum critical current density occures when DS = 67 mol%, and the maximum value (J = 3.5 X 10 Acm, 77K) when DS = 81 mol%. The critical current density is also affected by the conditions of treatment (calcination and pyrolysis), which is associated with the peculiarities of the distribution of the ceramics over the fibers. High-T). superconductor nanocomposites have also been prepared by polymerization of acrylic acid in an aqueous solution of Y + nitrate and Ba + and Cu " acetates. " ... 

The most common polyester fiber is polyethylene terephthalate (PET), prepared from ethylene glycol and terephthalic acid. Acrylics... 

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. 

Of a large number of possible fluorinated acrylates, the homopolymers and copolymers of fluoroalkyl acrylates and methacrylates are the most suitable for practical applications. They are used in the manufacture of plastic lightguides (optical fibers) resists water-, oil-, and dirt-repellent coatings and other advanced applications [14]. Several rather complex methods to prepare the a-fluoroalkyl monomers (e.g., a-phenyl fluoroacrylates, a-(trifluoromethyl) acrylic and its esters, esters of perfluoromethacrylic acid) exist and are discussed in some detail in [14]. Generally, a-fluoroacrylates polymerize more readily than corresponding nonfluorinated acrylates and methacrylates, mostly by free radical mechanism [15], Copolymerization of fluoroacrylates has been carried out in bulk, solution, or emulsion initiated with peroxides, azobisisobutyronitrile, or y-irradiation [16]. Fluoroalkyl methacrylates and acrylates also polymerize by anionic mechanism, but the polymerization rates are considerably slower than those of radical polymerization [17]. 

Epoxy resin adhesives for aluminum, glass, and steel have been prepared by converting octaallyl or octacrotyl-sucrose to the corresponding epoxides which were cured with diethylenetriamine.157 Several plastics, resins, and adhesives have been based on soybean oil.158 Vinyl esters of the fatty acids can be used as monomers. The oil can be epoxidized, then hydrolyzed to glycols, which can be converted to acrylates or maleates for polymerization. Natural fibers, such as hemp, can be used with such materials to form inexpensive composites. 

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