Polipirol/Bentonit İletken Kompozitine Radyasyon Etkilerinin Araştırılması

Yıl 2012, Cilt: 7 Sayı: 2, 112 - 122, 06.12.2012

Orhan Karabulut , Tahir Tilki , Mustafa Yavuz , Abdullah Kaplan , Duygu Takanoğlu Mehmet Çabuk , Seda Doğan

Öz

Bu çalışmada, polipirol/bentonit (PPy/Bnt) kompoziti, Bnt tabakaları arasında kimyasal oksidasyon polimerizasyonu yoluyla sentezlendi. Radyasyon uygulaması 60Co kaynağının kullanıldığı bir gama çemberi içerisinde hava ortamında gerçekleştirildi ve kompozite 40 kGy doz uygulandı. Kompozite radyasyon etkileri, FTIR, UV, TGA, XRD, SEM ve 290-410 K sıcaklık aralığında sıcaklığa bağlı elektriksel iletkenlik ölçümleri ile incelendi. Saf PPy/Bnt kompozitinin başlangıç bozunma sıcaklığı radyasyona uğramış PPy/Bnt kompozitinden daha yüksek olduğu bulundu. XRD desenlerine ait pik yoğunluğunun radyasyon ile değiştiği görüldü. Sıcaklığa bağlı iletkenlik ölçümlerinden radyasyonlanma sonucunda, PPy/Bnt kompozitin iletkenliğinin önemli ölçüde etkilediği gözlendi. İletkenlik sonuçları, hem saf PPy/Bnt hem de radyasyona uğramış kompozitlerde baskın iletim mekanizmasının Fermi seviyesi civarındaki seviyeler arasında hoplama yolu ile olduğu göstermiştir.

Anahtar Kelimeler

Polipirol, bentonit, iletken kompozit, gama radyasyonu

Investigation of Irradiation Effects on Conducting Composite of Polypyrole/Bentonite

Öz

In the present study, polypyrrole/bentonite (PPy/Bnt)
composite was synthesized into the Bnt interlayers by chemical oxidation
polymerization. The irradiation process was carried out in air in a
conventional gamma chamber, which uses a 60Co source, and the composite
was exposed to a dose of 40 kGy. Effects of irradiation on the composite
were investigated by means of FTIR, UV-visible absorption, TGA, XRD,
SEM and temperature dependent electrical conductivity in the temperature
range of 290-410 K. The initial decomposition temperature of pristine
PPy/Bnt composite was found higher than irradiated PPy/Bnt composite.
The XRD patterns revealed that the intensity of the peaks changed with
irradiation. It was found from temperature dependent conductivity
measurements that the radiation significantly influenced the
conductivity of PPy/Bnt composite. The conductivity results show that
dominant conduction mechanisms were hopping for both PPy/Bnt composite
and irradiated samples due to wide range of localized states present
near the Fermi level.

Anahtar Kelimeler

Polypyrrole, bentonite, conducting composite, gamma irradiation

Kaynakça

• Wang W., Yu D., Tian F., 2008. Synthesis and characterization of a new polypyrrole based on N-vinyl pyrrole, Synthetic Metals, 158: 717-721.
• Lagaly G., 1999. Introduction: from clay mineral-polymer interactions to clay mineral-polymer nanocomposites, Applied Clay Science, 15: 1-9.
• Letaief S., Aranda P., Ruiz-Hitzky E., 2005. Influence of iron in the formation of conductive polypyrrole-clay nanocomposites, Applied Clay Science, 28: 183-198.
• Abbes I.B., Srasra E., 2010. Characterization and AC conductivity of polyaniline–montmorillonite nanocomposites synthesized by mechanical/chemical reaction, Reactive and Functional Polymers, 70: 11-18.
• Kim B., Jung J.H., Hong S.H., Joo J., Epstein A.J., Ji K.M., Kim W., Choi H.J., 2002. Nanocomposite of Polyaniline and Na+−Montmorillonite Clay, Macromolecules, 35: 1419-1423.
• Aghamiri S.M.R., Namedanian M., Sanjabi Z., 2008. Effect of gamma irradiation on the light polarization variation of PMMA polymer, Optics Communation, 281: 356-359.
• Mayer J.W., Eriksson L.E., Davies J.A., 1970. Ion Implantation in Semiconductors, Academic press, New York and London.
• Wang Y.Q., Bridwell L.B., Giedd R.E., Murphy M.J., 1991. Effects of dose rate on the electrical conductivity of ion implanted polymers, Nuclear Instruments and Methods in Physics Research B, 56: 660-663.
• Dhillon A., Kaur A., Avasthi D.K., 2010. Electrical and morphological properties of poly(3-hexyl thiophene) irradiated with 100 MeV silver ions, Thin Solid Films, 519: 998-1002.
• Sarmah S., Kumar A., 2010. SHI irradiation effects on electrical and optical properties of PPy-SnO2 nanocomposite, Physica Status Solidi A, 207: 2279-2287.
• Forrest S.R., Kaplan M.L., Schmidt P.H., Venkatesan T., Lovinger A.J., 1982. Large conductivity changes in ion beam irradiated organic thin films, Applied Physic Letter, 41: 708-710.
• Kang H.C., Geckeler K.E., 2000. Enhanced electrical conductivity of polypyrrole prepared by chemical oxidative polymerization: Effect of the preparation technique and polymer additive, Polymer, 41: 6931-6934.
• Gök A., Omastova M., Prokes J., 2007. Synthesis and characterization of red mud/polyaniline composites: Electrical properties and thermal stability, European Polymer Journal, 43: 2471- 2480.
• Guinier A., 1963. X-ray difraction in crystals, imperfect crystals and amorphous bodies, W.H. Freeman and Company, San Francisco.
• Song K.T., Lee J.Y., Kim H.D., Kim D.Y., Kim S.Y., Kim C.Y., 2000. Solvent effects on the characteristics of soluble polypyrrole, Synthetic Metals, 110: 57-63.
• Karim M.R., Lee C.J., Chowdhury A.M.S., Nahar N., Lee M.S., 2007. Radiolytic synthesis of conducting polypyrrole/carbon nanotube composites, Material Letters, 61: 688-1692.
• Dimitry O.I.H., Abdeen Z.I., Ismail E.A., Saad A.L.G., 2010. Preparation and properties of elastomeric polyurethane/organically modified montmorillonite nanocomposites, Journal of Polymer Resulation, 17: 801-813.
• Theng B.K.G., 1974. The chemistry of clay organic reactions, Adams Hilger, London.
• Yoshimoto S., Ohashi F., Kameyama T., 2004. Simple preparation of sulfate anion-doped polyaniline-clay nanocomposites by an environmentally friendly mechanochemical synthesis route, Macromolecules Rapid Communation, 25: 1687-1691.
• Suljovrujic E., Ignjatovic N., Uskokovic D., 2003. Gamma irradiation processing of hydroxyapatite/poly-L-lactide composite biomaterial, Radiation Physics and Chemistry, 67: 375-379.
• Mott N.F., Davis E.A., 1973. Electronic process in non-crystalline materials, Clarendon Press, Oxford.
• Paul D.K., Mitra S.S., 1973. Evaluation of Mott's parameters for hopping conduction in amorphous Ge-Si and Se-Si, Physics Review Letters, 31: 1000-1003.
• Chandara S., Annapoorni S., Singh F., Sonkawade R.G., Rana J.M.S., Ramola R.C., 2010.Nuclear Instruments and Methods in Physics Research B, 268: 62-66.
• Mustafa Yavuz e-mail: [e-mail]
• Abdullah Kaplan e-mail: [e-mail]
• Orhan Karabulut e-mail: [e-mail]
• Tahir Tilki e-mail: [e-mail]
• Mehmet Çabuk e-mail: [e-mail]
• Duygu Takanoğlu email: [e-mail]
• Seda Doğan e-mail: [e-mail]