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Journal Articles

Ion-track grafting of vinylbenzyl chloride into poly(ethylene-$$co$$-tetrafluoroethylene) films using different media

Nuryanthi, N.*; Yamaki, Tetsuya; Kitamura, Akane; Koshikawa, Hiroshi; Yoshimura, Kimio; Sawada, Shinichi; Hasegawa, Shin; Asano, Masaharu; Maekawa, Yasunari; Suzuki, Akihiro*; et al.

Transactions of the Materials Research Society of Japan, 40(4), p.359 - 362, 2015/12

The ion-track grafting of a vinylbenzyl chloride (VBC) into a poly(ethylene-co-tetrafluoroethylene) (ETFE) film is necessary for preparing nanostructured hydroxide-ion-conductive electrolyte membranes. A key for success here is to obtain as high graft levels as possible (for higher conductivity) in a smaller number of tracks (for improving the other membrane properties). To this end, therefore, the effect of the medium for the VBC grafting was investigated as part of our continuing effort to optimize the experimental conditions. A 25 $$mu$$m-thick ETFE film was irradiated in a vacuum chamber with 560 MeV $$^{129}$$Xe at different fluences, and then the grafting was performed by immersing the irradiated films in a 20vol% VBC monomer at 60$$^{circ}$$C. A medium was a mixture of water (H$$_{2}$$O) and isopropyl alcohol (iPrOH) at different volume ratios. The degree of grafting increased as the H$$_{2}$$O content became higher, and reached a maximum in pure H$$_{2}$$O. These results can be explained by considering the well-known Trommsdorff effect, in which poor solubility of the grafted polymer in polar media leads to an increased polymerization rate probably due to a lower termination rate.

Journal Articles

Journal Articles

Development of highly proton-conductive membranes based on crosslinked fluoropolymers by radiation chemical methods

Yamaki, Tetsuya; Yoshida, Masaru

Nenryo Denchi, 4(3), p.73 - 78, 2005/01

no abstracts in English

Oral presentation

Ion-track grafting of vinylbenzyl chloride into poly(ethylene-co-tetrafluoroethylene) films using different media; Comparison with $$gamma$$-ray-induced grafting

Nuryanthi, N.*; Yamaki, Tetsuya; Kitamura, Akane; Koshikawa, Hiroshi; Yoshimura, Kimio; Sawada, Shinichi; Hasegawa, Shin; Asano, Masaharu; Maekawa, Yasunari; Suzuki, Akihiro*; et al.

no journal, , 

The ion-track grafting of a vinylbenzyl chloride (VBC) into a poly(ethylene-co-tetrafluoroethylene) (ETFE) film is necessary for preparing nanostructured hydroxide-ion conductive electrolyte membranes. A key for success here is to obtain as high graft levels as possible (for higher conductivity) in a smaller number of tracks (for improving the other membrane properties). To this end, therefore, the effect of the medium for the VBC grafting was investigated as part of our continuing effort to optimize the experimental conditions. A 25 $$mu$$m-thick ETFE film was irradiated in a vacuum chamber with 560 MeV $$^{129}$$Xe at different fluences, and then the grafting was performed by immersing the irradiated films in a 20vol% VBC monomer at 60$$^{circ}$$C. A medium was a mixture of water (H$$_{2}$$O) and isopropyl alcohol (iPrOH) at different volume ratios. The degree of grafting increased as the H$$_{2}$$O content became higher, and reached a maximum in pure H$$_{2}$$O.

Oral presentation

Ion-track grafting of vinylbenzyl chloride into poly(ethylene-co-tetrafluoroethylene) films; Kinetic analysis of reaction-medium effects

Yamaki, Tetsuya; Nuryanthi, N.*; Kitamura, Akane; Koshikawa, Hiroshi; Yoshimura, Kimio; Sawada, Shinichi; Asano, Masaharu*; Maekawa, Yasunari; Suzuki, Akihiro*; Terai, Takayuki*

no journal, , 

We investigated the ion-track grafting of vinylbenzyl chloride (VBC) into a poly(ethylene-${it co}$-tetrafluoroethylene) (ETFE) film using different grafting media for applications as anion exchange membranes for fuel cells. In an attempt to increase the grafting yield, we applied a poor solvent system as the grafting medium, ${it i.e.}$, a mixture of water and isopropyl alcohol (H$$_{2}$$O-${it i}$PrOH mixture). The optimum H$$_{2}$$O-${it i}$PrOH composition was identified by the kinetic parameters including the initial polymerization rate (r$$_{p0}$$), the radical recombination rate ($$gamma$$) and the grafting efficiency (r$$_{p0}$$/$$gamma$$). These parameters changed depending on the VBC-grafting/chain-transfer reaction competition for the radicals on ETFE and the Trommsdorff effect; the swelling of the grafting substrate gave an additional effect.

Oral presentation

Track structure effect on the ion-track grafting of vinylbenzyl chloride into poly(ethylene-${it co}$-tetrafluoroethylene) films

Nuryanthi, N.*; Yamaki, Tetsuya; Saiki, Seiichi; Kitamura, Akane; Koshikawa, Hiroshi; Yoshimura, Kimio; Sawada, Shinichi; Terai, Takayuki*

no journal, , 

This study deals with the ion-track grafting of vinylbenzyl chloride (VBC) into poly(ethylene-${it co}$-tetrafluoroethylene) (ETFE) film irradiated with 560 MeV $$^{129}$$Xe and 330 MeV $$^{40}$$Ar for the application to anion exchange membrane fuel cells (AEMFC). The accelerated ions with different masses and energies enabled us to clarify the effect of the LET and radial dose distribution in the track on the ETFE film. The lower-LET Ar ion gave the higher degree of VBC grafting than the higher-LET Xe ion although its radial dose distribution showed smaller track size. This study gave an insight of the importance to study the track structure in relation with the final membrane properties of the AEMFC.

Oral presentation

Preparation and characterization of anion exchange membranes for fuel cell applications by ion-track grafting polymerization

Nuryanthi, N.*; Yamaki, Tetsuya; Kitamura, Akane; Koshikawa, Hiroshi; Sawada, Shinichi; Yoshimura, Kimio; Terai, Takayuki*

no journal, , 

Swift heavy ions with kinetic energies of MeV to GeV will create cylindrical tracks along their trajectories in a polymer film. These tracks of tens to hundreds nanometers in diameter contain free radicals; they can be used as initiators for graft polymerization. The so-called ion-track grafting technique was used for the development of anion exchange membranes (AEMs). The OH$$^{-}$$ conductivities at 60$$^{circ}$$C in the fully-hydrated state were higher for ion-track-grafted membranes than for the conventional $$gamma$$-ray-grafted ones at the certain same IEC. Due to a lower diffusion coefficient of OH$$^{-}$$, improving the conductivity has been one of the most challenging problems in AEM studies. In this sense, we found the ion-track grafting to be very promising.

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