Radiation-induced Graft Polymerization Research Articles

Separation of U and Pu in spent nuclear fuel sample using anion-exchange-group-introduced porous polymer sheet for ICP-MS determination

Anion-exchange porous sheets were prepared by radiation-induced graft polymerization and subsequent chemical modifications. A diethylamino (DEA) group as an anion-exchange group was introduced into the polymer chain grafted onto a porous sheet. The DEA group-introduced porous sheet was cut into disks 13 mm in diameter and 3 mm in thickness to fit an empty cylindrical cartridge (DEA cartridge). The DEA sheet had a DEA group of 3.4 mol/kg of the DEA-group-containing porous sheet and a linear velocity of 46 m/h at a permeation pressure of 0.1 MPa at 298 K. The adsorption capacity of the DEA cartridge for FeCl 4 − as a model ion in equilibrium with 1 g-Fe(III)/L in 10 M HCl was 0.17 mmol-Fe(III)/DEA cartridge. No Pu leakage during the permeation of 5 mL of 10 M HCl–0.1 M HNO 3 containing Pu ionic species through the DEA cartridge was observed irrespective of the permeation rate ranging from 0.3 to 80 mL/min. A solution containing known amounts of 233U, 240Pu, and 241Am in 10 M HCl–0.1 M HNO 3 was loaded onto the DEA cartridge. U and Pu were retained on the DEA cartridge, while Am was allowed to pass through the DEA cartridge. Subsequently, 7 M HNO 3 and 1 M HCl as eluents were permeated to elute U and Pu from the DEA cartridge, respectively. The decontamination factor of U in a Pu fraction, defined by dividing the activity of U in the feed solution by that of U in the Pu fraction, was 2.7 × 10 5, which is desirable for the highly accurate ICP-MS determination of Pu for samples containing both U and Pu. The method using the DEA cartridge was validated by measuring isotopic compositions and quantities of U and Pu in a spent nuclear fuel sample by double-focusing magnetic sector ICP-MS.

Preparation of polymer electrolyte membranes consisting of alkyl sulfonic acid for a fuel cell using radiation grafting and subsequent substitution/elimination reactions

Polymer electrolyte membranes (PEMs) consisting of alkylsulfonic acid were successfully synthesized by radiation-induced graft polymerization of methyl acrylate (MA) into a poly(ethylene- co-tetrafluoroethylene) (ETFE) film, followed by sulfonation at an α-carbonyl carbon of the MA units in the grafting chain using an equimolar complex of chlorosulfonic acid and dioxane (ClSO 3H-complex). Sulfonation reaction with ClSO 3H-complex in the grafted chains of acrylic acid derivatives (acrylic acid and N, N-dimethylacrylamide) other than MA in the film could not be performed. The ion-exchange capacity (IEC) and ion conductivity of the MA-grafted PEM were controlled in the respective ranges of 0.54–1.47 mmol/g and 0.014–0.14 S/cm by changing the grafting degree. It has been confirmed by titrimetric and gravimetric analyses of sulfonic and carboxylic acids in the film that the sulfonation reaction is accompanied with decarboxylation of the MA units equimolar to the substituted sulfonic acids (substitution of carboxylic acid with sulfonic acid), and that the sulfonation degree was ca. 30%.

A novel process to develop modified polymeric surfaces for the analysis of bacterial adhesion: Surface properties and adhesion test

AbstractSurface of polypropylene (PP) sheets were modified by radiation induced graft polymerization of a mixture of two monomers, a quaternary ammonium salt ([2‐(methacryloyloxy)ethyl]‐trimethyl ammonium chloride) (QAS) and acrylic acid(AA) to control the bacterial adhesion. Electron beam radiation was used to activate PP sheets prior to the grafting reaction. Depth concentration profile of nitrogen on modified PP up to 10 nm was performed by XPS. However, XPS has revealed no significant changes in the concentration profile of nitrogen for the grafted PP prepared under different parameters. Energetic characteristics (Lifshitz‐van der Waals (γLW), electron acceptor (γ+), and electron donor (γ−) components) of these modified surfaces (with different ratio of comonomer mixtures) were calculated by using contact angle measurements. The PP surfaces prepared under one specific ratio of comonomer mixture (AA : QAS) 20 : 40 (M‐4) has been compared with the surfaces modified with 20% AA (AA‐20) and 40% QAS (QAS‐40). The surface charge and isoelectric point have been determined by zeta potential measurements. AA‐20 and comonomer mixture modified PP (M‐4) surfaces exhibit negative charges of −27 and −16, respectively, while QAS‐40 modified PP surfaces show positive charge of +16. The physicochemical properties of Listeria monocytogenes (LM) were obtained by microbial adhesion to solvent method. Finally, adhesion of LM on unmodified and modified PP surfaces was observed by electron microscopy. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Preparation of Patterned Polymer Brushes by Radiation-Induced Grafting

Surface modi cation of polytetra uoroethylene lm was carried out by radiation-induced graft polymerization. This lm was rst modi ed prior to graft polymerization by Ar+ ion irradiation in order to activate the surface. Subsequently, graft polymerization of acrylic acid onto the activated surface was carried out under aqueous conditions to create patterned polymer brushes of poly(acrylic acid). The structure of the grafted surface was characterized by using Fourier transform-infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM).

Microfiltration membranes prepared from polyethersulfone powder grafted with acrylic acid by simultaneous irradiation and their pH dependence

Polyethersulfone (PES) powder was grafted with acrylic acid (AAc) by simultaneous γ-ray irradiation. The kinetics of the radiation induced graft polymerization was studied and the grafted PES powder was characterized. Then, microfiltration (MF) membranes were prepared from PES-g-PAAc powder with different degrees of grafting (DG) under phase inversion method. The swelling behavior and the mean pore size of MF membranes were measured, and the filtration property was tested. The results showed that the pore size and the flux of MF membranes increased with the increase in DG. And, MF membranes’ properties were dependent on the pH value.

Surface treatment of PET fiber by EB-irradiation-induced graft polymerization and its effect on adhesion in natural rubber matrix

Aiming to develop a high performance fiber-reinforced natural rubber (NR) without using resorcinol formaldehyde latex (RFL) adhesives of environmental load substances, a special technique using electron beam (EB) irradiation-induced graft polymerization was applied to high-modulus polyethylene terephthalate (PET) fibers. Although PET is chemically inert, acrylate functional silane could be graft-polymerized onto the PET fiber surface by this special technique. The composite of NR and grafted PET fibers indicated a linear increase in the initial modulus with the fiber content. The fiber reinforced rubber with a good performance was obtained in the system of NR and grafted PET fibers.

微生物固定化のための膜の改質と水処理分野への適用

微生物固定化のための膜の改質と水処理分野への適用

放射線グラフト重合法による膜の改質が可能にする抽出試薬担持材料の作製

放射線グラフト重合法による膜の改質が可能にする抽出試薬担持材料の作製

High-throughput solid-phase extraction of metal ions using an iminodiacetate chelating porous disk prepared by graft polymerization

A chelating porous sheet for use in solid-phase extraction was prepared by radiation-induced graft polymerization and subsequent chemical modifications. An epoxy-group-containing vinyl monomer was graft-polymerized onto a porous sheet made of polyethylene. The produced epoxy group of the graft chain was converted into an iminodiacetate group. The chelating porous sheet with a density of the iminodiacetate group of 2.1 mol/kg was cut into disks 13 mm in diameter to fit an empty cylindrical cartridge with a capacity of 6 mL. Breakthrough curves using the chelating-porous-disk-packed cartridge overlapped irrespective of the flow rate of the solution ranging up to 1500 mL/h because of negligible diffusional mass-transfer resistance of the copper ions to the iminodiacetate group of the graft chain.

Synthesis of a cation-exchange fabric with sulfonate groups by radiation-induced graft copolymerization from binary monomer mixtures

Cation-exchange adsorbent based on a nonwoven polypropylene fabric carrying sulfonate functional groups was synthesized by a one-step graft copolymerization of sodium styrenesulfonate and acrylic acid monomers from binary monomer mixtures using the electron beam pre-irradiation method in air. The effect of various polymerization parameters (absorbed dose, reaction temperature and time, monomer ratio, Mohr’s salt additive) on the degree of grafting was studied. It was found that the copolymerization process begins with the primary grafting of acrylic acid monomers on the nonwoven polypropylene fabric and continues by cografting of sodium styrenesulfonate and acrylic acid monomers. Total ion-exchange capacity and sulfonate group density were evaluated to vary within 3.5–5.5 and 1.0–2.16mEq/g, correspondingly, for synthesized fabrics with a medium grafting degree (70–220%). These values are similar to those of sulfonated membranes obtained by radiation-induced graft polymerization of styrene with subsequent sulfonation of polystyrene chains. The main advantage of the studied approach is a one-step process of synthesis.

Gelatin Immobilization on Titanium Surface by Gamma Irradiation

Radiation induced graft polymerization of 2-hydroxyethyl acrylate (HEMA) on titanium surface and couple gelatin have been studied in the paper. The composition and properties of surface modified titanium were investigated by several surface sensitive techniques: X-ray photoelectron spectrum (XPS) and scanning electron microscopy (SEM). Results of the technological measurements show that surface chemistry is affected throughout the surface modification process, finally leading to a complete and homogeneous vinyl compound overlayer on top of the titanium samples. And the modified porous titanium exhibits an interesting mineralization in simulated body fluid (SBF) and an adsorptive property in bovine serum albumin (BSA).

Preparation and properties of novel fishnet fibers with inhibitory effects on the adhesion of seaweeds

A novel Nylon-6 fiber with the anti-adhesion of seaweeds was prepared for the use of fishnet by the technique of graft modification. The modification was performed by UV radiation-induced graft polymerization of Poly(acrylic acid) (PAA) onto Nylon-6 fibers, and to form crosslinked PAA hydrogels on the surface of them. The structure of the anti-adhesion fibers was investigated by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). The mechanical properties and water retention capacity were measured, respectively. Three kinds of seaweeds (Chlorella, Dunaliella and Chrysophyte) were employed to evaluate the inhibitory effects on the adhesion. The results showed that Nylon-6 fibers modified by PAA hydrogels had a strong effect on the adhesion of the three kinds of seaweeds. The effects were improved with the increase of the grafting amount. Results from the mechanical analysis revealed that the tensile strength of the modified fibers decreased, however, the ratio of elongation increased with the increase of the grafting amount. The novel fibers also showed a good water retention capacity.

Verification of Controlled Grafting of Styrene from Cellulose via Radiation-Induced RAFT Polymerization

Reversible addition - fragmentation chain transfer (RAFT) polymerization was applied to radiation-induced graft polymerization of styrene from cellulose. The grafting of styrene from cellulose substrates using the chain transfer agent cumyl phenyldithioacetate was confirmed by Raman and X-ray photoelectron spectroscopy, differential scanning calorimetery, thermogravimetric analysis, scanning electron microscopy, and contact angle analysis. Grafted polystyrene chains were cleaved from the cellulose surface by acidic hydrolysis of the cellulose. The number-average molecular weight and polydispersity index of the grafted and the free (nongrafted) polystyrenes obtained under identical conditions were determined by size exclusion chromatography. Grafted and nongrafted polystyrenes have almost the same (near theoretical) molecular weight and narrow polydispersity, thus proving for the first time the control of the grafting process mediated via RAFT without any prior functionalization of the surface.

Radiation-induced grafting of dimethylaminoethylmethacrylate onto PE/PP nonwoven fabric

A new adsorbent was prepared by radiation-induced graft polymerization of dimethylaminoethylmethacrylate (DMAEMA) onto polyethylene/polypropylene (PE/PP) nonwoven fabric. The trunk polymer was irradiated by electron beam at a voltage of 2 MeV and a current of 3 mA in nitrogen atmosphere at dry-ice temperature to different doses. The degree of grafting was determined as a function of irradiation dose, monomer concentration, temperature and reaction time. Grafting conditions were optimized and about 150% grafted samples were used for further experiments. DMAEMA grafted polymer was later protonated in acid solution to prepare specialty adsorbent for the removal of phosphate. Adsorption experiments were performed in column mode for removal of phosphate. It was shown that 2000 bed volumes of phosphate-free water can be produced from 100 ppb phosphate (as P) solution at high space velocity.

Separation functional fibers by radiation induced graft polymerization and application

Commercially available non-woven fabric made of polyolefines was used as trunk polymer for radiation induced graft polymerization (RIGP). Ion exchange, antimicrobial and catalytic function was introduced on the fabric by RIGP. All of these materials are commercialized. Ion exchange fabric prepared by RIGP are applied for chemical filter to remove ionic impurities in semiconductor factory and are also applied for continuous de-ionization apparatus to make pure water in combination with ion conductive spacer. Polyvinylpyrrolidone–iodide grafted fabric was produced as antimicrobial fabric and applied for mask. Metal oxide nanoparticle was immobilized onto the ion exchange fabric. This material has catalytic function and was applied for the removal of ozone from air. In all of these applications, long sheets of non-woven fabrics are applied as a trunk polymer. Manufacturing process of RIGP for long sheet is also reported here.

Radiation-induced graft polymerization of maleic acid and maleic anhydride onto ultra-fine powdered styrene–butadiene rubber (UFSBR)

The functionalization of ultra-fine powdered styrene–butadiene rubber (UFSBR) was carried out using gamma radiation-induced graft polymerization of maleic acid (MA) and maleic anhydride (MAH), respectively. It was found that the graft yield of MA onto UFSBR increased rapidly up to the peak and then decreased with increasing MA content. Moreover, the peak shifted to the direction of lower MA content with increasing absorbed dose. Similarly, there was the peak of graft yield with increasing MAH content for grafting of MAH onto UFSBR, whereas the peak of graft yield was achieved at 10 wt% MAH content at different absorbed doses. On the other hand, increasing absorbed dose and decreasing monomer contents are useful to improve the graft efficiency of MA and MAH. At high dose and low monomer content, the graft yield of MAH onto UFSBR is higher than that of MA. FTIR spectra confirmed that both MA and MAH can be grafted successfully onto the UFSBR under gamma irradiation, respectively. Comparing with maleation of rubber by melt grafting, the graft yield of MAH on UFSBR is higher, which can be attributed to the network structure and nanometer size of UFSBR as well as high energy provided by radiation.

Design of polymer brushes for immobilizing enzymes onto hollow fiber micropores in organic media reaction

To immobilize lipase for enzymatic reactions in organic solvent, various functional [epoxy (GMA-fiber), hydroxyl (OH-fiber) or diethyl amino (DEA-fiber)] groups were introduced onto porous hollow-fiber membranes by radiation-induced graft polymerization of glycidyl methacrylate and chemical modification. Lipase from Candida rugosa was immobilized on polymer brushes by permeation of lipase. The activities of immobilized lipase were measured by esterification reactions between lauric acid and benzyl alcohol in isooctane. The activity of immobilized lipase on GMA-fibers, DEA-fibers and OH-fibers was 0.70 mol/(h kg -lipase), 0.50 mol/(h kg -lipase), and 2.45 mol/(h kg -lipase), respectively. Immobilized lipase on DEA-fibers or OH-fibers was reused three times after it was used in the batch reactor for 24 h. It was found that lipase activity showed no signs of denaturation. However, when native lipase was used, lipase activity remarkably decreased after reusing.

Effect of γ-ray irradiation grafting on the carbon fibers and interfacial adhesion of epoxy composites

A special technique using γ-ray irradiation-induced graft-polymerization was applied to carbon fibers. Epoxy resin and chloroepoxy propane reacted with carbon fibers by a co-irradiation grafting method and acrylic acid was graft-polymerized onto the fiber surface via a pre-irradiation grafting method. The roughness, amount of containing-oxygen functional groups and surface energy were all found to increase significantly after irradiation grafting. Gamma-ray irradiation grafting improved marginally the tensile strength of carbon fibers, which was evaluated by statistical analysis using the Weibull distribution. The interlaminar shear strength of treated carbon fiber/epoxy was enhanced by at least 17.5%, compared with that of untreated carbon fiber/epoxy. The mechanisms of irradiation grafting are proposed by radical reactions. The γ-ray co-irradiation grafting and pre-irradiation grafting are both an effective method for modifying the physicochemical properties of carbon fibers and improving the interfacial adhesion of composites.

Preparation of ion exchange membranes by radiation grafting of acrylic acid on FEP films

Ion exchange membranes were prepared by radiation induced graft polymerization of acrylic acid on FEP films using preirradiation method. The influence of the ferrous sulfate and monomer concentration on the degree of grafting was investigated. Divinylbenzene, tetraethyleneglycol dimethacrylate and methylene bisacrylamide were used as crosslinkers. The membranes were characterized by FTIR, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and X-ray diffraction analysis. The swelling bahavior and specific resistivity of membranes as function of the degree of grafting and crosslink nature were evaluated. These crosslinkers had influence on the swelling and the specific resistivity of membranes depending on their chemical nature.

Biodegradability of poly(3-hydroxybutyrate) film grafted with vinyl acetate: Effect of grafting and saponification

Radiation-induced graft polymerization of vinyl acetate (VAc) onto poly(3-hydroxybutyrate) (PHB) film was carried out. At a degree of grafting higher than 5%, the grafted films (PHB-g-VAc) completely lost the enzymatic degradability that is characteristic of PHB due to the grafted VAc covering the surface of the PHB film. However, the biodegradability of the PHB-g-VAc films was recovered when the films were saponified in alkali solution under optimum conditions. Graft chains of the PHB-g-VAc film reacted selectively to become biodegradable polyvinyl alcohol (PVA). The biodegradability of the saponified PHB-g-VAc film increased rapidly with time.