Radiation-induced Graft Polymerization Research Articles

Effect of Shape and Size of Amidoxime-Group-Containing Adsorbent on the Recovery of Uranium from Seawater

Abstract An amidoxime-group-containing adsorbent for the recovery of uranium from seawater was synthesized by radiation-induced graft polymerization of acrylonitrile onto polypropylene fiber of round and cross-shaped sections. The tensile strength and elongation of the synthesized adsorbent, both of which were one-half those of the raw material, were not affected by the shape of the fiber. The deterioration of the adsorption ability induced by immersing the adsorbent in HC1 was negligible because of the short immersion time required for the desorption with HC1. The concentration factors for uranium and transition metals in 28 days were in the order of 105, while those for alkali metals and alkaline earth metals were in the order 10−1-101. The recovery of uranium with the cross-shaped adsorbent was superior to that of the round-shaped one. XMA line profiles show that the distribution of uranium is much restricted to the surface layer when compared with that of alkaline earth metals. Diminishing the diamete...

Characteristics of uranium adsorption by amidoxime membrane synthesized by radiationinduced graft polymerization

Chelating membranes containing amidoxime groups for the recovery of uranium were synthesized by the radiation-induced graft polymerization of acrylonitrile onto high- and low-density polyethylene films, followed by amidoximation of the cyano groups. The amidoxime group contents of both chelating membranes were about 2.0 tool per kilogram of HCl-conditioned membrane. Both amidoxime-group-containing membranes showed maximum uranium adsorption capacity for uranyl solutions between pH 5 and 7. Uranium permeability of the low-density-polyethylene-based chelating membrane was found to be much better than that of the high-densitypolyethylene-based chelating membrane.

A New Type of Amidoxime-Group-Containing Adsorbent for the Recovery of Uranium from Seawater. III. Recycle Use of Adsorbent

Abstract An amidoxime-group-containing adsorbent for recovering uranium from seawater was made by radiation-induced graft polymerization of acrylonitrile onto polymeric fiber, followed by amidoximation. Uranium adsorption of the adsorbent contacted with seawater in a column increased with the increase in flow rate, then leveled off. The relationship between uranium adsorption in a batch process and the ratio of the amount of seawater to that of adsorbent was found to be effective in evaluating adsorbent contacted with any amount of seawater. The conditioning of the adsorbent with an alkaline solution at higher temperature (80°C) after the acid desorption recovered the adsorption ability to the original level. This made it possible to apply the adsorbent to recycle use. On the other hand, the adsorbent conditioned at room temperature or that without conditioning lost adsorption ability during recycle use. The increase in water uptake was observed as one of the physical changes produced during recycle use o...

Preparation and reactivity of metal-containing monomers. Communication 4. Radiation-induced graft polymerization of acrylamide complexes of Co(II), Ni(II), and Cu(II) on polyethylene

1. Graft polymerization of acrylamide complexes of Co(II) and Ni(II) from an alcoholic solution was carried out on polyethylene powder pre-irradiated in air, and graft copolymers containing up to 1 mass % metal were obtained. 2. The process of graft polymerization of acrylamide complexes of Co(II) and Ni(II) occurred at rates close to the rate of grafting of acrylamide under comparable conditions, and it was characterized by practically complete absence of thermal homopolymerization. Grafting of the acrylamide complex of Cu(II) practically did not occur. 3. The initial rate of graft polymerization of the Co(II) and Ni(II) complexes depended linearly on the concentration of the metal-containing monomer in the solution and the concentration of hydroperoxy groups in irradiated polyethylene.

放射線グラフト重合法によるウラン吸着用中空糸状アミドオキシム樹脂の合成

中空糸状の多孔性ポリエチレン樹脂を基材とし,放射線グラフト重合法によりシアノ基を導入しグラフト率が79%から127%の4種類のアクリロニトリル樹脂を得た。それぞれをヒドロキシルアミン溶液と反応させてアミドオキシム型キレート樹脂を合成した。元素分析によりアミドキシム化反応における窒素導入量を求めたところ19基材あたり4.3mmo1から8.5mmolであった。導入された窒素の大部分はアミドオキシム基になっていると考えられる。基材において広範囲に分布する細孔半径は,グのラフト反応により分布が狭くなり1000Åあたりに集中した。19樹脂あたりの細孔容積は,2.5cm3/gからおよそ半分に減少したが,1g基材あたりの細孔容積はグラフト率とともに増大し,グラフト率が127%のとき4.5cm3/g-基材となった。比表面積は基材の場合30m2/gであるがグラフト率の増大にともなって減少し,グラフト率が127%のとき15m2/gとなった。アミドキシム化反応における窒素導入量に対し,塩酸および銅はいずれも1.5倍の吸着量を示した。IR測定の結果をも考慮して副反応による酸アミド,ヒドロキサム酸の生成を推定した。導入窒素1原子に対しウラン吸着量は0.64原子の割合であった。

Radiation-induced graft polymerization of acrylamide: Reverse osmosis properties of polyethylene-g-poly(acrylamide) membrane

A study has been made of some properties of the graft copolymer obtained by direct radiation grafting of acrylamide (AAm) onto low density polyethylene (LDPE) films. The swelling behaviour was investigated for the grafted and alkali-treated graft copolymer and it was found that this depends mainly on the amount of hydrophilic groups and also on the type of electrolytes (K- or Nasalts). salts). Some other properties of the graft copolymer films such as dimensional change wet and dry, electrical conductivity, and mechanical properties were studied. A trial has been made of such membrane for reverse osmosis desalination of saline water. The effect of operating time, degree of grafting, applied pressure and feed concentration on the water flux and salt rejection was determined.

Modification of polyethylene by radiation-induced graft polymerization of acrylic acid

The kinetics investigation of the radiation-induced graft polymerization of acrylic acid onto low density polyethylene by direct method in aqueous solution in the presence of Mohr's salt, was performed. The technique of the contrasting of polyacrylic acid (PAA) graft layer was worked out by Ag +-ions. The structural and morphological peculiarities of grafted copolymers of PE with PAA were determined by the method of electron probe, and X-ray microanalysis by means of the electron microscopy.

A New Type of Amidoxime-Group-Containing Adsorbent for the Recovery of Uranium from Seawater

Abstract A new type of adsorbent containing amidoxime groups for the recovery of uranium from seawater was synthesized by the radiation-induced graft polymerization of acrylonitrile onto polymeric fiber followed by amidoximation with hydroxylamine. When amidoxime groups were introduced superficially on the fiber, the amount of uranium adsorbed by the amidoxime groups was higher than that with the amidoxime groups introduced homogeneously in the fiber. The introduction of the poly(acrylic acid) chain and the increase in temperature and flow rate in the adsorption process were effective in increasing the amount of adsorbed uranium. Although alkali metals and alkaline earth metals were found in the adsorbent, the concentration factors for these metals were less than 1/103 of that for uranium. The present adsorbent had a high stability to various treatments such as contact with alkali and seawater.

Complex-forming polymer prepared by electron beam radiation-induced graft polymerization

In order to prepare a complex-forming polymer useful as a selective adsorbent, radiation-induced graft polymerization of acrylonitrile onto a fibrous tetrafluoroethylene ethylene copolymer has been studied by using preirradiation method. The resulting grafted fibers were treated with 3% hydroxylamine alcohol-water solution, followed by controlling in alkali solution. The adsorbents containing amidoxime are able to take up transition metal ions from neutral and weakly acidic solutions while not sorbing the ions of alkaline and alkaline earth metals to any significant extent. It was shown that by introducing a small amount of hydrophilic groups to the fiber, it was possible to increase the exchange rate between the external water and the internal water interacted with functional groups in polymer matrix and to induce the diffusion of hydrated metal ions. The efficiency for adsorption of transition metal ions was successfully improved either by adding small amount of hydrophilic part composed of poly(acrylic acid) or by restricting the distribution of amidoxime groups at the fiber surface. A high stability of this adsorbents to various treatments ( alkali treatment at 80° C, contact with seawater for 24 h at 30° C, etc.) was confirmed. It's applicability to the recovery of uranium from seawater is demonstrated by laboratory scale experiments.

Radiation-induced ionic graft polymerization

Radiation-induced ionic graft polymerization

Preparation and morphology of polyelectrolyte complex coatings based on polyacrylic acid and polyethylene imine

A method of radiation induced graft polymerization of acrylic acid and subsequent treatment with polyethylene imine has been used to deposit a coating of a poly-electrolyte complex on polyethylene. The radiation induced grafting of acrylic acid from an aqueous solution without oxygen and in the presence of atmospheric oxygen has been investigated. A study of the surface shows that the grafted layer is inhomogeneous and that there is partial penetration of grafting into the volume. After the subsequent deposition of polyethylene imine on the surface of the grafted layer, globular structures of the polyelectrolyte complex, measuring 300–1000 Å, are formed. Even after contact with blood, no change in the surface structure was observed.

Functional Monomers and Polymers. 90 Radiation-Induced Graft Polymerization of Styrene onto Chitin and Chitosan

Abstract The graft polymerization of styrene onto chitin powder, and chitosan powder and film initiated by γ-ray irradiation was carried out at 30°C. The graft polymerization was found to proceed predominantly in the presence of water, and the degree of grafting increased with an increase in the radiation dose. From ESR spectroscopy it was noted that the free radicals generated both in chitin and in chitosan were stable enough at ambient temperature. Styrene-grafted chitin and chitosan powders thus obtained showed less swelling in water, and chitosan after graft polymerization was insoluble in dilute acids. Graft polymerization of other vinyl monomers was also studied.

Radiation-induced low-temperature cationic graft polymerization of vinyl-n-butyl ether to polyvinyl chloride in the glass transition

A gravimetric study was made of radiation-induced cationic graft polymerization of vinyl-n-butyl ether using a PVC film in the temperature range of −60 to + 10°. In order to effect grafting, PVC films swollen in 50% monomer solution in benzene, were subjected to radiation using a 60Co γ-source and a dose of 10 krad. Maximum grafting was observed in the range of devitrification of the swollen reaction system. The glass-transition range was determined by thermomechenical analysis and the thermostimulated current method. When studying grafting in the glass-transition region according to the dose of radiation it was found that the rate of grafting above 10 krad decreases markedly even before the initial monomer is fully depleted inside the film. A possible interpretation is proposed for the effects observed.

The radiation-induced graft polymerization of acryloyl chloride to polyethylene and polyethylene terephthalate

The radiation-induced graft polymerization of acryloyl chloride to PE and PETP has been investigated. Features of the formation and decay of radicals when polymer specimens are in contact with vapours of the monomer being grafted are revealed, and molecular weights of the grafted chains evaluated. It is shown that differences in the chemical and physical structure of PE and PETP account for a difference in processes of acryloyl chloride grafting to the polymer matrices, and for a difference in MW of the grafted chains.

Radiation-induced graft polymerization of acrylic acid to powdered low-pressure polyethylene

A study was made of kinetics of graft polymerization of acrylic acid in 5% (by volume) solution of heptane at 343°K to high-pressure powdered PE exposed to radiation in air at 295°K up to 5–200 kJ/kg. A graft copolymer was obtained containing up to 40 wt.% polyacr ylic acid. It was shown that in the presence of 0·08% cobalt palmitate the initial rate of grafting is doubled. Experimental results were compared with calculated ones assuming that grafting was initiated by radicals formed during decomposition of peroxide groups and with bimolecular chain termination.

Radiation induced ionic polymerisation and grafting of vinyl monomers

AbstractSome special aspects of the radiation induced ionic polymerisation and grafting of vinyl monomers will be described. In particular the effects of solvents on the cationic polymerisation of the vinyl ethers will be discussed in detail. The unequivocal free ion nature of the polymerisation makes such information of considerable general interest. Estimates of the propagation rate constants with free cation polymerisation in solvents of different dietectric constants and solvation powers will be presented. Finally, some observations on the radiation induced graft polymerisation of ethyl vinyl ether to poly (vinyl chloride) and to polypropylene will be presented.

Radiation-Induced Graft Polymerization of 4-Vinylpyridine on Polyethylene

4-Vinylpyridine was grafted on polyethylene films of different thicknesses by the direct irradiation method using a Co-60 γ-irradiation source. Addition of different amounts of solvents such as methyl ethyl ketone and cyclohexanone was found to decrease the swelling and the grafting extent on polyethylene. The dependence of the rate of graft polymerization on the thickness of the films was studied. The rate of grafting was found to decrease with increasing film thickness and a first order dependence was obtained. The effect of radiation dose on some of the mechanical properties of the ungrafted and grafted polyethylene was examined. It was found that low doses cause an increase in elongation due to a degradation process of polyethylene chains. At high doses, elongation tends to decrease again due to crosslinking, while the tensile load is not affected. Low grafting percents of 4-vinylpyridine on polyethylene lead to a marked decrease in elongation of the grafted polymer, with almost no change in the tensile load. Increasing the extent of grafting causes a significant increase in the tensile load and almost the same decrease in elongation as for the low grafted polymer.

Radiation-Induced Grafting of Ethyl Vinyl Ether onto Polyvinyl Chloride)

Abstract The radiation-induced graft polymerization of ethyl vinyl ether (EVE) onto polyvinyl chloride) (PVC) was studied under a variety of conditions. Graft copolymer and homopoly(EVE) were formed in all cases. The presence of water reduced overall polymerization rates, percentage grafting, and homopoly(EVE) molecular weights. With “superdry” EVE, grafting reached 29% at a total dose of 6.9 Mrad. Grafting to PVC films was less efficient than grafting to PVC powder. Application of a relatively poor swelling agent for PVC resulted in an increase in the efficiency of grafting. From a comparison of studies of radiation-induced EVE homopolymerization and the present work, it was concluded that dry and superdry EVE are grafted to PVC by a cationic mechanism and wet EVE is grafted mainly by a free-radical mechanism.

Radiation grafting of methacrylates onto silicone rubber: Prototype burn wound dressing

The radiation-induced graft polymerization of 2-hydroxyethyl methacrylate (HEMA) and ethylene glycol dimethacrylate (EGDMA) to silicone rubber (Silastic) sheeting has been investigated with the aim of developing an elastomeric composite for use as a burn dressing material. Polymerization is initiated by 60Co γ-ray irradiation of the elastomer immersed in an aqueous solution of monomer. Some of the physical parameters associated with grafting from aqueous solution are characterized. Factors influencing the depth and morphology of the grafts include dose, dose rate, monomer concentration and purity, and the extent of the competing homopolymerization reactions.

Development of a continuous process for radiation-induced graft polymerization of butadiene onto poly (vinyl chloride)

A continuous process with large radiation sources was developed for radiation-induced graft polymerization of butadiene gas onto poly(vinyl chloride) powder. A stirred moving bed type reactor was selected on the basis of simplicity of structure and high efficiency of production. The calculated distribution curve of dose rate with cylindrical 60Co gamma ray sources installed in the center of the reactor approximately agreed with the observed values. The distribution of temperature of the powder layer was almost uniform in the radial direction due to the agitation of powder with blades. The geometrical standard deviation of the grafting yield in the axial direction of the reactor decreased from 2.9 to 1.2 on approaching the outlet of the reactor. The mechanical properties and the cost of the graft polymer produced with this process made it clear that the commercialization of the process was promising.