Naslov
Radiation modification of (PEO)8ZnCl2 polyelectrolte and nanocomposite

Autori
Pucić, Irina ; Turković, Aleksandra

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
7th International Symposium on Systems with Fast Ionic Transport (ISSFIT ) : Programme and book of abstracts / Gaberšček, Miran - Ljubljana : National Institute of Chemistry Ljubljana, 2004, 65-65

Skup
International Symposium on Systems with Fast Ionic Transport (7 ; 2004)

Mjesto i datum
Bled, Slovenija, 05.05.2004. - 09.05.2004

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
DSC; impedance spectroscopy; polyelectrolyte

Sažetak
Poly(ethylene oxide), PEO, is semi-crystalline polymer frequently used to prepare polyelectrolyte complexes of increasing importance [1] especially if the conductivity in temperature range between room temperature and 100°C could be increased above 10-3 (Ω cm)-1. Since charge transport in amorphous phase is 2 to 3 orders of magnitude faster than in crystalline phase, intention is to prepare films with higher content of amorphous phase while keeping or improving its mechanical properties. This can be achieved by partial crosslinking of PEO thus reducing the space for spherulites formation and growth, what can be initiated chemically, photo-chemically or by ionizing radiation. Further improvements can be achieved by addition of nano-grains. The polymer-salt complexes were prepared by dissolving ZnCl2 and PEO in ethanol-water solution in stoichiometric proportions. PEO was used as received or previously cross-linked by g-irradiation to selected doses in 60Co irradiation facility at Ruđer Bošković Institute. Nanocomposite films were prepared by stirring nanometer-sized grains of TiO2 into solution. The polymer-salt complex solution was then poured onto a Teflon plate and resulting films were dried and stored in desiccators. Melting, crystallization temperatures and corresponding heats of prepared films were measured by DSC, FTIR spectra were recorded and films were investigated by optical microscopy. The crosslinked films had lower heats of fusion and crystallization, while further decrease of corresponding nanocomposites was caused mostly by dilution effect The impedance spectroscopy measurements were performed on a home made impedance meter with a frequency range from 10 Hz to 1 MHz, in temperature range between room temperature and 110°C using nonblocking Zn electrodes. The results were consistent with RC-circuits model [2] and the conductivity steeply increased with total radiation dose up to 10-1 (Ω cm)-1. The transition temperatures were in good agreement with DSC results. The film prepared from PEO that received highest dose showed somewhat lower conductivity and poor mechanical properties, its FTIR spectra showed changes that can be ascribed to degradation. Nanocomposites showed further improvement of conductivity and mechanical properties compared to corresponding PEO films prepared without nano-TiO2 grains. Optical micrographs of unirradiated PEO-ZnCl2 complex showed distinct spherulites. Both radiation cross-linking and addition of nanoparticles reduced the size of spherulites that become invisible for nanocomposite prepared of PEO irradiated to medium dose of 200 kGy. These preliminary results show the need for further investigation of radiation processing of PEO with the goal of finding optimal radiation conditions for production of films and nanocomposites with desired electrical and mechanical properties. References [1] FB.Dias, L. Plomp and J.B.J. Veldhuis, Trends in polymer electrolytes for secondary lithium batteries, Journal of Power Sources 88, (2000) 169-191. [2] A.Turković and Z.Crnjak Orel, "Electrical and Optical Properties of Thin Films Zn/(PEO)4ZnCl2/CeO2, or CeO2/SnO2(17%), ITO Galvanic Cells", Solid State Ionics 89 (3-4), (1996) 255.

Izvorni jezik
Engleski

Znanstvena područja
Poljoprivreda (agronomija)

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