Geliştirilmiş elektrik iletkenliğine sahip POT/Na-Feldispat iletken kompozitlerinin sentezlenmesi ve karakterizasyonu

Abstract

Bu çalışmada iletken POT/Sodyum Feldispat kompoziti in-situ kimyasal polimerizasyon yöntemi ile hazırlandı. Sodyum Feldispat partikülleri varlığında asidik sulu ortamda hazırlanan kompozitin iletkenliği ve %POT verimi üzerine sodyum feldispatın tanecik boyutunun ve polimerizasyon koşullarının etkisi araştırıldı. En yüksek elektriksel iletkenlik ve verim için en uygun reaksiyon koşulları 45µm altı partikül boyutundaki Na-Feldispat, 1 M HCl, 0.3 M o-toluidin, 0.0375 M K2Cr2O7 ve 0°C sıcaklık olarak belirlendi. En yüksek POT verimi ve elektriksel iletkenlik değerleri sırasıyla %24.51 ve 22×10-5 Scm-1 bulundu. Hazırlanan kompozitin karakterizasyonu, kompozitin bileşenlerinin saf halleri ile karşılaştırılmalı olarak Fourier dönüşümlü kızılötesi spektroskopisi (FTIR), X-ışınları kırınımı (XRD), termal gravimetrik analiz (TGA) ve taramalı elektron mikroskop (SEM) teknikleri kullanılarak yapıldı.

Recently, conductive polymeric materials have attracted a lot of interest in scientific and technological fields. Among all conducting polymers, polyaniline are of great interest due to easy synthesis, good environmental stability and its high conductivity. However, the main problem is the weak mechanical properties and workability of PANı based on insoluble in common organic solvents. This problem is resolved to some extent through the use of derivatives such as N-methyl or N-ethyl aniline, toluidine and anisidine instead of aniline. In these days, organic-inorganic nanohybrid materials known as polymer nanocomposites have become an effective alternative for many applications. Inorganic materials are used for imparting new and superior properties to composites. Conductive POT/Na-Feldspar composite was prepared by chemical polymerization of o-toluidine in the presence of Na-Feldspar using K2Cr2O7 as oxidant in the acidic aqueous solution. A systematic study on the preparation of conductive POT/NaFeldspar composite has been conducted by varying reaction parameters such as the particle size of NaFeldspar, concentration of K2Cr2O7, monomer and HCl and reaction temperature. The effect of the reaction parameters on the conductivity of composites was also investigated. As a result, optimum reaction parameters were determined for the synthesis of the POT/Na-Feldspar composite with the highest electrical conductivity. Since the properties of composites have been effected with particle size, shape and chemical structures of inorganic materials, we examined the effect of the particle size of Na-Feldspar on the composite first. A result of the analysis for 4 different size of Na-Feldspar, it was seen that the efficiency of polymerization was close to each other and the dimension did not affect the yield of polymerization. The highest conductivity of prepared composite with particle size of NaFeldspar below 45 µm was observed as 1.3058?10-5 S/cm. When the effect of oxidant concentration on the electrical conductivity of prepared composite was examined, the conductivity increased to 20.56×10-5 Scm-1 with increasing oxidant concentration from 0.02 to 0.0375 M range. In a similar sensitivity study, when the effect of monomer concentration on the electrical conductivity of the prepared composites was examined, the conductivity first increased with increasing monomer concentration 0.1-0.3 M first and stayed nearly constant from 0.3 to 0.5 M. In addition, the effect of the polymerization temperature on the electrical conductivity of the prepared composite was also studied by varying the temperature between 0 and 70 ºC. The results indicated that the conductivity decreases with increasing the temperature in this range. The highest electrical conductivity of prepared composite at 0 ºC polymerization temperature was observed as 21.7?10-5 S/cm. Finally, the effect of acid concentration on the electrical conductivity of the composite was investigated by changing HCl concentration between 0.025 and 3 M. In this sensitivity study, the results indicated that the conductivity increases slightly from 21.7×10-5 to 22×10-5 Scm-1 at 1 M HCl concentration. After varying reaction parameters, the conductivity of the POT/Na-Feldspar composite was increased to a value of 22×10-5 Scm-1 than 1.3058?10-5 Scm-1 . According to these results, a feasible reaction parameters for highest POT content and conductivity of the composite have been specified as a particle size below 45 µm of Na-Feldspar, 0.0375 M K2Cr2O7, 0.3 M o-toluidine, 1 M HCI and 0°C reaction tempereature for 2 h reaction time. The POT content and conductivity of the composite reached to the maximum values of 24.51% and 22×10-5 Scm-1 , respectively. The structural, morphological and thermal properties of composite with the highest conductivity and POT content were analyzed using FTIR, XRD, TGA and SEM techniques. SEM images and XRD diffractograms of the POT/Na-Feldspar composite and its components demonstrated that POT was coated on the surface of Na-Feldspar platelets. Furthermore, the TGA analysis results showed that the thermal stability of the conductive POT/Na-Feldspar composite was among its components.