• Polymer(Korea)
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• v.37 no.5
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• pp.649-655
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• 2013

In order to use as supporters for the reinforced composite fuel cell membrane, poly(acrylic acid)-grafted porous polytetrafluoroethylenes (PTFEs) were prepared via introduction of poly(acrylic acid) graft chains by a radiation grafting method. FTIR was utilized to confirm the successful introduction of poly(acrylic acid) graft polymer chains into the porous PTFEs. Contact angles were examined to observe the hydrophilicity of the surface of the prepared substrates. The result indicates that the hyrophilicity of the surface in the prepared substrates increases with an increase in the number of hydrophilic polymer chains. FE-SEM, gurley number, and tensile strength were also utilized to characterize the prepared substrates.

• Polymer(Korea)
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• v.26 no.3
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• pp.287-292
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• 2002

Graft copolymerization of styrene and glycidyl methacrylate (GMA) to the peroxidized polypropylene (PP) fabric with E-beam in $O_2$ atmosphere was carried out in vapor phase with benzoyl peroxide (BPO) as an initiator. The degree of grafting of copolymers was increased with the increase of the reaction temperature and the highest degree of grafting was obtained at $70^{\circ}C$ with styrene, and at $80^{\circ}C$ with GMA. The highest degree of grafting of styrene grafted PP according to reaction time was higher than that of GMA grafted PP. In vapor phase graft polymerization, the degree of grafting of copolymers according to water composition in monomer mixture was effected by the boiling temperature of monomers.

• Polymer(Korea)
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• v.34 no.1
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• pp.20-24
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• 2010

In this study, ETFE-g-PSSA membranes with various degrees of grafting (DOG) and thicknesses were prepared by a simultaneous irradiation method. SEM-EDX instrument was applied to measure the relative distribution of sulfur which is corresponding to that of a grafted polymer over the Cross-section of the ETFE-g-PSSA membranes prepared at various irradiation conditions. The results indicate that to obtain the evenly-grafted membranes, a styrene/dichloromethane ratio is needed to be under 60 (v/v%), and a higher DOG is required as the film thickness increases. The effects of DOG and thickness on the ion exchanging capacity (IEC) and water uptake (WU) were investigated by measuring the IEC and WU values of the membranes with various DOG and thicknesses.

• Journal of Radiation Industry
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• v.4 no.4
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• pp.341-345
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• 2010

The surface functionalization of a fluoropolymer by ion beam-induced graft polymerization was described in this research. The surface of poly(tetrafluoroethylene) (PTFE) films were irradiated by a 150 keV $H^+$ ions, and 4-vinyl pyridine (4VP) as a functional monomer was then thermally graft polymerized on the irradiated surface. The surface properties of poly(4-vinyl pyridine) (P4VP)-grafted PTFE films were investigated in terms of grafting degree, wettability, chemical structure, and morphology. The results revealed that the surface of PTFE films was successfully functionalized by ion beam-induced graft polymerization of 4VP.

• Journal of Radiation Industry
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• v.6 no.4
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• pp.289-297
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• 2012

Since Nafion is very expensive and shows the decreased fuel cell performance over $80^{\circ}C$ operating temperature, much work has been carried out in the search for cheaper membrane with high fuel cell performance. Radiation is known to be very useful for the preparation of the polymer electrolyte membranes since it can be effectively used for the introduction of ion conducting functional groups into the commercial film with high mechanical and chemical properties. Here, we summarize the our recent progress in the development of fuel cell membranes by utilizing radiation.

• Analytical Science and Technology
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• v.12 no.1
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• pp.7-12
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• 1999

The cation-exchange adsorbent (CEA) was prepared by radiation-induced grafting of glycidyl methacrylate (GMA) onto polypropylene (PP) fabric and its subsequently phosphonation. The adsorption characteristics of $Pb^{2+}$, $Cu^{2+}$ and $Co^{2+}$ for the CEA were discussed. In the grafting of GMA onto PP fabric, the degree of grafting (%) increased with increasing reaction time, reaction temperature, and pre-irradiation dose. The maximum grafting yield was observed around 60% GMA concentration. The content of phosphoric acid ranges from 2.5 to 3.5 mmol/g with the 85% phosphoric acid. The adsorption of $Pb^{2+}$, $Cu^{2+}$ and $Co^{2+}$ by the CEA was enhanced with increasing phosphoric acid content. The order of adsorption capacity of CEA was $Pb^{2+}$>$Co^{2+}$>$Cu^{2+}$.

• Polymer(Korea)
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• v.31 no.1
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• pp.1-7
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• 2007

In this study, the sulfonated ion exchange fiber was synthesized by $Co^{60}\;{\gamma}-ray$ radiation-induced graft copolymerization. Degree of grafting (DG) increased with increasing the total dose and showed the highest value at 50 v/v% styrene monomer. And also, the degree of sulfonation (DS) increased with increasing the DG and reaction temperature. DS showed the maximum value at 20 min. Ion exchange capacity and swelling ratio of ion exchange fibers increased with increasing the DS and their maximum values were 4.76 meq/g and 23.5%, respectively. Ammonia adsorption increased as increasing the ammonia concentration and ion exchange capacity and remained constant over 10 cycles.

• Applied Chemistry for Engineering
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• v.9 no.4
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• pp.516-522
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• 1998

In this study, a water adsorbent was synthesized by radiation grafting of acrylic acid and multifunctional monomers such as 1,2-propanediol dimethacrylate (PDMA) and 1,1,1-trimethylolethane triacrylate (TMETA) onto cellulose and its subsequent treatment with 5% NaOH. Its absorbency on $H_2O$ and 0.9 % NaCl aqueous solution was examined. The highest absorbency on water and on 0.9% NaCl aqueous solution was obtained from the addition of 0.75 vol % PDDMA and of 1.0 vol % TMETA onto acrylic acid solution, respectively. The absorbency of commercial hygienic band on water and NaCl aqueous solution was 21 g/g and 22 g/g, respectively. However, that for acrylic acid-grafted cellulose including TMETA was 298 g/g and 54 g/g, respectively.

• Nuclear Engineering and Technology
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• v.12 no.1
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• pp.1-8
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• 1980

The grafting studies were concentrated on working out the methodology for radiation of flame retardants to polyester/cotton (65/35) blend fabric. The Fyrol 76 was used as a flame retardant in develping methodology for localizing flame retardants on the surface of the blend fabric. By judicious control of the swelling conditions, time_of contact with the monomer, and dose rate, locating the graft in the fiber became possible. The yield of the graft polymerization was depended upon the total dose and the preswelling conditions. Oxygen Index was used to evaluate the effect of the location of Fyrol 76 and other flame retardants within the surface upon the flame retardance efficiencies. To get a better flame retardance efficiency by :the localized grafting of Fyrol 76 to polyester/cotton blend fabric, a technique of one step processing at room temperature was developed substituting the ordinary two-step processing at high temperature.

• Nuclear Engineering and Technology
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• v.8 no.2
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• pp.89-99
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• 1976

The grafting of acrylic acid in aqueous solution to polyvinyl chloride fibers tab been studied in the presence of ferrous, ferric, and cupric salts, The mutual irradiation technique was adopted using a Co-60 source or a Van do Graaff accelerator. The grafting and homopolymerization were suppressed by the cations. Particularly the grafting was suppressed by the cations in the following order of effectiveness : $Cu^{2+}$>$Fe^{2+}$>$Cu^{3+}$. The rate of grafting (in %/hr) was proportional to the 0.76th power of the dose rate over the range from 8.5f $10^3$ rad/hr to $1.4\times10^5$ rad/dr. The apparent activation energy for the grafting was determined to be 6.1 Kcal/mole between $25^{\circ}$ and $75^{\circ}C$ for the mixture of AA-HaO-$(CH_2Cl)_2$, containing Mohr's salt, $4\times10^{-3}$ mole/l. The increase of the grafting was observed when total dose and dose intensity were raised, or when ethylene dichloride as a swelling agent was saturated in the monomer mixture. The grafted polyvinyl chloride fibers showed considerable improvement in moisture regain, heat shrinkage, and melting properties, but tensile properties were not significantly affected by grafting.