Graft Copolymers Of Acrylonitrile Research Articles

Graft Copolymerization of Acrylonitrile and Ethyl Methacrylate on Dextrin

Graft copolymers of Acrylonitrile and ethyl methcrylate on dextrin were prepared by the use of ceric ion initiator in aqueous medium at 290C. The molecular weight of grafted poly(ethyl methacrylate) chains were higher than for polyacrylonitrile grafts; but the latter were more frequently grafted on the backbone polymer. The dependence of the molecular weight of the grafted chains on ceric ion concentration suggests that interaction of growing graft polymer chains with ceric ion is important in the termination process of graft copolymerisation. Graft copolymeriation of ethyl methacrylate onto dextrin in the presence of various amounts of acrylonitrile was studied. The compositions of the copolymer samples, calculated from their nitrogen content, showed that in the presence of ethyl acrylate, relatively small amounts of acrylonitrile monomer was grafted onto dextrin. Nigerian Journal of Chemical Research Vol. 11 2006: pp. 22-27

Structure and Characteristics of Graft Copolymers with Chitosan

Graft copolymers of acrylonitrile with chitosan were prepared by radical polymerization of acrylonitrile in aqueous acetic acid solution of chitosan.

Synthesis of high rubber styrene–EPDM–acrylonitrile graft copolymer and its toughening effect on SAN

AbstractHigh rubber styrene–EPDM–acrylonitrile (AES) was prepared by the graft copolymerization of styrene (St) and acrylonitrile (AN) onto ethylene–propylene–diene terpolymer (EPDM) in n‐heptane/toluene cosolvent using benzoyl peroxide as an initiator. The effects of reaction conditions, such as reaction temperature, initiator concentration, EPDM content, the solvent component, and reaction time, on the graft copolymerization are discussed. In addition, according to the research on mechanical properties of the SAN/AES blend, a remarkable toughening effect of AES on SAN resin was found. By means of scanning electron microscopy, the toughening mechanism is proposed to be crazing initiation from rubber particles and shear deformation of SAN matrix. Uniform dispersion of rubber particles, as shown by transmission electron microscopy, is attributed to the good compatibility of SAN and AES. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 416–423, 2004

Graft copolymerization of acrylonitrile on kenaf fibers by ceric ion in the presence of allyl compounds

Graft copolymers of acrylonitrile on kenaf fibers were obtained in an aqueous medium by the use of allyl alcohol and allyl chloride in combination with ceric ion as redox pairs. The graft copolymerization reactions showed distinct features that were associated with different initiating species derived from the redox pairs. For a ceric–allyl-chloride-initiated reaction, a minimum graft yield was observed, accompanied by an enhanced graft yield. This suggested the existence of two kinetically controlled grafting reactions arising from two different initiating species. For the ceric–allyl-alcohol-initiated reaction, the grafting profile showed a maximum yield and suggested the presence of one active initiating species. High concentrations of acrylonitrile were favorable to grafting with values of up to 150%, but they also resulted in decreased efficiency in monomer conversion to grafted polymer. The frequency of grafting increased with the concentration of allyl alcohol but the molecular weight of grafted polymer of up to 4.46 × 104 decreased by a factor of one and half over the concentration range 1.8–9.0 × 10−4M of the latter. The presence of 10% (v/v) N,N′-dimethylformamide resulted in zero graft, but the same vol % of formic acid had no apparent effect on the graft yield. A negative temperature dependence in the graft yield was found in the temperature range of 50–70°C. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 1757–1761, 1999

Graft copolymerization of acrylonitrile on kenaf fibers by ceric ion in the presence of allyl compounds

Graft copolymers of acrylonitrile on kenaf fibers were obtained in an aqueous medium by the use of allyl alcohol and allyl chloride in combination with ceric ion as redox pairs. The graft copolymerization reactions showed distinct features that were associated with different initiating species derived from the redox pairs. For a cericallyl-chloride-initiated reaction, a minimum graft yield was observed, accompanied by an enhanced graft yield. This suggested the existence of two kinetically controlled grafting reactions arising from two different initiating species. For the ceric-allyl-alcohol-initiated reaction, the grafting profile showed a maximum yield and suggested the presence of one active initiating species. High concentrations of acrylonitrile were favorable to grafting with values of up to 150%, but they also resulted in decreased efficiency in monomer conversion to grafted polymer. The frequency of grafting increased with the concentration of allyl alcohol but the molecular weight of grafted polymer of up to 4.46 x 10 4 decreased by a factor of one and half over the concentration range 1.8-9.0 x 10 -4 M of the latter. The presence of 10% (v/v) N,N'-dimethylformamide resulted in zero graft, but the same vol % of formic acid had no apparent effect on the graft yield. A negative temperature dependence in the graft yield was found in the temperature range of 50-70°C.

Graft copolymerization of vinyl monomers on cellulosic materials

Graft copolymers of acrylonitrile, ethyl acrylate, methyl acrylate, ethyl methacrylate and methyl methacrylate and of acrylonitrile/ethyl methacrylate and acrylonitrile/methyl methacrylate monomer mixtures on carboxymethylcellulose (degree of substitution 0.4-0.5) were prepared by use of ceric ion initiator in aqueous medium. The extent of graft polymer formation was measured in terms of graft level. molecular weight of grafted polymer chains and frequency of grafting as function of ceric ion concentration. It was found that at comparable reaction conditions, the molecular weight and frequency of grafting were not of the same order of magnitude. For the monomer mixtures, the copolymer compositions obtained from the total nitrogen content of the acrylonitrile/alkyl methacrylate copolymer samples showed that a relativity low amount of the acrylonitrile monomeric units were incorporated into the graft copolymer even at high acrylonitrile content of the feed.

Preparation and evaluation of the chitin derivatives for wastewater treatments

The chitin thiocarbonate—Fe(II)H—H2O2 redox system was investigated as the initiator for the graft copolymerization of acrylonitrile and acrylic acid monomers onto chitin powder. The reaction with vinyl monomers onto chitin was carried out under various parameters of the graft copolymerization reaction to elucidate the polymerization behavior in terms of graft yield. Reactions of chitin—acrylonitrile graft copolymer with hydroxyl amine hydrochloride, as well as, sodium hydroxide were conducted in order to obtain chitin—(amidoxime-co-acrylonitrile) and chitin-(acrylate-co-acrylamide) graft copolymers, respectively. The reaction efficiency depends upon the alkali concentration, time, temperature, and on the reactant concentrations. The prepared chitin derivatives were evaluated for use in the wastewater treatments for adsorption and desorption of heavy metal ions as well as acid and basic dyes. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 1939–1946, 1997

Synthesis and application of poly(butadiene-g-acrylonitrile-styrene) core-shell rubber particles for use in epoxy resin toughening. I. Synthesis of poly(butadiene-g-acrylonitrile-styrene)

Graft copolymers of acrylonitrile (AN)–styrene (ST) onto polybutadiene were prepared via emulsion polymerization method using a redox initiator system, cumene hydroperoxide–tetrasodium pyrophosphate–ferrous sulfate–dextrose. The effects of initiator, reaction temperature, reaction time, polymer/grafting monomer ratio, and monomer dropping frequency on the graft copolymerization reaction were investigated. Transmission electron micrographs confirmed that the synthesized particles had a core–shell shaped structure. The powdery core–shell shaped poly(butadiene-g-AN–ST) particles with various AN contents in their shells and with different shell thicknesses were prepared, which can be incorporated into brittle epoxy resin as impact modifier. © 1996 John Wiley & Sons, Inc.

Graft copolymerizations of modified cellulose, grafting of acrylonitrile, and methyl methacrylate on carboxy methyl cellulose

Graft copolymers of acrylonitrile (ACN), methyl methacrylate (MMA), and their mixtures on carboxy methyl cellulose (d.S 0.4–0.5) were prepared by the use of ceric ion initiator in aqueous medium. The graft copolymers were characterized by IR spectroscopy. The extent of graft copolymerization of ACN and MMA was measured in terms of graft level, molecular weight of grafted polymer chains, and the frequency of grafting as functions of ceric ion concentration. It was found that at comparable reaction conditions, the molecular weight of the grafted polymer chains and the frequency of grafting were not of the same order of magnitude. For the monomer mixtures, the copolymer compositions obtained from the total nitrogen contents of the copolymer samples showed that a disproportionately low amount of ACN monomeric units were incorporated into the graft copolymer, even at high ACN content of the feed. © 1996 John Wiley & Sons, Inc.

Thermal behaviour of graft copolymers of sodium alginate

AbstractThe thermal stability of sodium alginate (SA) and its graft copolymers of acrylonitrile (AN), methyl acrylate (MA), ethyl acrylate (EA) and methyl methacrylate (MMA) has been examined in air atmosphere by means of thermogravimetric analysis. The following order of decreasing stability was found from characteristic decomposition temperatures: SA‐g‐PAN > SA‐g‐PMA > SA‐g‐PEA > SA‐g‐PMMA. The overall thermal stability of the different SA graft copolymers was evaluated by comparing their activation energies of thermal degradation; it agreed with the same order of thermal stability.

Preparation of fibres from graft copolymers of acrylonitrile and polyvinyl alcohol

The possibility of spinning fibres from graft copolymers of polyvinyl alcohol and acryonitrile by the scheme for spinning polyacrylonitrile fibre has been established. It has been shown that spinning solutions can be prepared directly from latexes of the graft copolymers. The suggestion has been made that long side chains in the copolymers participate in formation of supermolecular structural elements and aid in obtaining fibres with adequately high mechanical strength and an increased thermal stability.

Studies on the graft copolymerization of acrylonitrile

Graft copolymers of acrylonitrile on bleached holocellulose and on starch were obtained at 29°C using ceric ions and the continuous initiation and depleted initiator methods. The extent of graft polymer formation (level of grafting and molecular weight of grafted chains) on starch was higher than on the bleached holocellulose. The extent of graft polymer formation using the depleted initiator method was higher than that obtained using the method of continuous initiation but grafts from the latter method were more frequent on the polymeric substrates.

Grafting acrylonitrile and methyl methacrylate on holocellulosic materials

Graft copolymers of acrylonitrile and methyl methacrylate on bleached holocellulose and thiolated holocellulose were obtained by the use of ceric ions in aqueous medium at 29°C. The level and efficiency of grafting on the bleached holocellulose were significantly higher than on the thiolated holocellulse, but the molecular weights and number of grafted copolymer chains on both the unmodified and thiolated holocellulose were similar. The graft level and molecular weight of acrylonitrile graft copolymer were significantly lower than those for methyl methacrylate at comparable ceric ion and monomer concentrations. These results indicate the significance of the influence of the polarity of monomer on the extent of graft copolymer formation and lead to the suggestion that graft copolymerization may not result entirely from radicals generated on the cellulose substrate.

Grafting acrylonitrile and acrylic acid monomers on cellulosic materials

AbstractGraft copolymers of acrylonitrile and of acrylic acid monomers on cellulosic materials were obtained by use of ceric ion initiator in aqueous medium at a 50% (w/w) cellulose‐monomer ratio. The variations of poly(acrylonitrile) grafts and of the efficiency of grafting with ceric ion concentration, and of poly(acrylic acid) grafts with temperature are examined. The dependence of water retention capacity of the grafted fibers with the graft level is reported.

Permselectivity of Liquid–Polymer Hybrid Membrane Composed of Carbon Tetrachloride and 2-Hydroxyethyl Acrylate– Acrylonitrile Graft Copolymer for Ethanol–Water Mixture

A membrane with selective permeability for ethanol was designed for the separation of ethanol from its aqueous solution by pervaporation on the basis of the difference in solubility between two components of the membrane. A liquid membrane was introduced to extend this difference and ethanol in the liquid membrane was isolated by the polymer membrane; that is, a liquid–polymer hybrid membrane was formed. Carbon tetrachloride was used as a liquid membrane, and 2-hydroxyethyl acrylate (HEA) (branch)–acrylonitrile (AN) (backbone) graft copolymer membrane was used as a polymer membrane. The effect of the microphase separated structure of the graft copolymer membrane on permselectivity was studied. The microdomain of the AN moiety displayed more dispersion and a smaller microdomain with decreasing chain length of the backbone polymer. It was found that the plasticizing effect was suppressed effectively by the microphase separated structure and the permselectivity of the graft copolymer membrane for ethanol was higher. When pervaporation of the ethanol–water mixture was carried out using the liquid–polymer hybrid membrane, ethanol completely permeated the liquid–polymer hybrid membrane.

Electron‐beam‐induced conduction in fluorinated ethylene propylene copolymer and its acrylonitrile graft copolymer

AbstractElectron‐beam‐induced conductivity (EBIC) studies were carried out on fluorinated ethylene propylene copolymer (FEP) and its acrylonitrile graft copolymer (FEP‐g‐AN). The current transport parallel to the surface under the influence of an electron beam of medium energy (6–30 keV) is reported. The gain in EBIC is calculated and its characteristic variation as a function of beam energy is studied. Minima in the gain versus energy curves have been obtained around 21 keV for FEP, 12 and 18 keV for FEP‐g‐AN, and 12 keV for polyacrylonitrile (PAN). This behavior is explained by assuming the existence of electron trapping bands close to the surface, at characteristic distances below the surface of the polymeric film corresponding to the range of incident electrons. Gains of the order of 5, 12, and 30 have been obtained respectively for FEP, FEP‐g‐AN, and PAN for the maximum energy of incident electrons used.

Part I. On the synthesis and pyrolysis of a tetrafluoroethylene–acrylonitrile graft copolymer

AbstractRadiation‐induced grafting of acrylonitrile onto films of polytetrafluoroethylene has been studied. Irradiation has been carried out in a 60Co gamma source at −78°C., and the graft polymerization was facilitated by being held at 100°C. for 150 hr. The amount of acrylonitrile grafted per unit surface area apparently increases with the thickness of the film. Grafting is also accompanied by slight swelling. This indicates that the reaction occurs in depth. The relative decrease of the amount of grafted acrylonitrile with thickness of the film, referred to the weight of the film, shows that grafting is controlled by the diffusion of the monomer. The rate of grafting was found to be lower in a material with a higher degree of crystallinity; i.e., grafting occurs faster in the amorphous areas of the polymer. The final yield of graft decreases with the temperature at which the reaction is carried out. This may be explained on the basis of kinetics or by assuming a simultaneous disappearance of free polymer radicals.

Carbochain polymers and copolymers—XLII. Graft copolymers of acrylonitrile and the methacrylate polyester of ω-hydroxyenanthic acid : G. S. Kolesnikov and G. T. Gurgenidze, Vysokomol. soyed. 4: No. 11, 1709–1713, 1962

Carbochain polymers and copolymers—XLII. Graft copolymers of acrylonitrile and the methacrylate polyester of ω-hydroxyenanthic acid : G. S. Kolesnikov and G. T. Gurgenidze, Vysokomol. soyed. 4: No. 11, 1709–1713, 1962