Physics / Fizik
Permanent URI for this collectionhttps://hdl.handle.net/11147/6
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Conference Object Citation - WoS: 39Citation - Scopus: 48Temperature Dependence of Electrical Conductivity in Double-Wall and Multi-Wall Carbon Nanotube/Polyester Nanocomposites(Springer Verlag, 2007) Şimşek, Yılmaz; Özyüzer, Lütfi; Seyhan, Abdullah Tuğrul; Tanoğlu, Metin; Schulte, KarlThe aim of this study is to investigate temperature dependence of electrical conductivity of carbon nanotube (CNT)/polyester nanocomposites from room temperature to 77 K using four-point probe test method. To produce nanocomposites, various types and amounts of CNTs (0.1, 0.3 and 0.5 wt.%) were dispersed via 3-roll mill technique within a specially formulized resin blend of thermoset polyesters. CNTs used in the study include multi walled carbon nanotubes (MWCNT) and double-walled carbon nanotubes (DWCNT) with and without amine functional groups (-NH2). It was observed that the incorporation of carbon nanotubes into resin blend yields electrically percolating networks and electrical conductivity of the resulting nanocomposites increases with increasing amount of nanotubes. However, nanocomposites containing amino functionalized carbon nanotubes exhibit relatively lower electrical conductivity compared to those with non-functionalized carbon nanotubes. To get better interpretation of the mechanism leading to conductive network via CNTs with and without amine functional groups, the experimental results were fitted to fluctuation-induced tunneling through the barriers between the metallic regions model. It was found that the results are in good agreement with prediction of proposed model.Article Citation - WoS: 3Citation - Scopus: 4Strain Gauges of Gasb-Fega1.3 Eutectic Composites(Springer Verlag, 2004) Aliyev, M.I.; Khalilova, A. A.; Arasly, D. H.; Rahimov, R. N.; Tanoğlu, Metin; Özyüzer, LütfiA needle-shaped metallic FeGa1.3 phase oriented in a specific direction and uniformly distributed within a GaSb matrix was grown by a vertical Bridgman method. Strain-gauge characteristics, such as strain-sensitivity coefficient (S), temperature coefficient of strain sensitivity (TCS) and temperature coefficient of resistance, of GaSb and GaSb-FeGa1.3 eutectic alloy have been investigated in the range of 200 to 400 K under deformation up to strains of 1.3 × 10-3. The value of S of the GaSb-FeGa1.3 composition is measured to be 40 ± 5 and its TCS is about 0.2% deg-1 when the current is perpendicular to the needles and the needles are parallel to the plane of the gauge substrate. The strain-sensitivity characteristics are linear and hysteresis free in the investigated temperature range in the aforementioned direction. It was found that GaSb-FeGa1.3-based strain gauges possess better deformation characteristics than GaSb-based gauges.