Çitosan/polipirol/kil nanokompozitlerinin sentezi ve karakterizasyonu

Many researchers studying on discovering new materials to enhance the quality of human life in all aspects. The challenging part of this quest is to find all desired properties in a single material. A composite material is composed of two or more constituents to unite all desired properties in one material. The goal of this study is to discover and produce a high conductivity nanocomposite which is biodegradable, biocompatible, and biofunctional so that it can be used in biomedical applications. Chitosan (CS) is chosen as one of the most attractive polymer due to its' specific properties; such as biocompatibility, biodegradability, and biofunctionality, etc. One of the most investigated conducting polymers is polypyrrole (PPy) because of its characteristics such as; easy synthesis and high conductivity. Recently, there have been many attempts to synthesize composites of CS and PPy to investigate what combined functionality can be obtained. Combination of pyrrole with cerium (IV) ammonium salts (Ce+4) exhibits better solubility than PPy. In aqueous media, redox systems of Ce+4 and reducing agents such as acids are well known initiators for vinyl polymerization. Polymerization reaction in aqueous media has many technical advantages than other methods. Additionally, the preparation of polymers with clay minerals has been extensively studied topic due to understand the synergistic effect of them. In this work, Chitosan/Polypyrrole composites and Chitosan/ Polypyrrole/ Sepiolite (Cs/PPy/Sep) Nanocomposites (NC) were synthesized via redox polymerization in aqueous media with magnetic stirrer system in presence of ammonium cerium (IV) nitrate (Ce+4) at room temperature. The roles of the oxidant/monomer mole ratio, on the yield, conductivity and morphology of the resulting products were investigated. Chitosan /Polypyrrole composites and Chitosan/ Polypyrrole/ Sepiolite Nanocomposites (Cs/PPy/Sep NC) were prepared with the oxidant to pyrrole mole ratios as 0.67:1, 0.8:1, and 1:1 for comparison. In addition, to understand the effect of inorganic agents to Cs/PPy/Sep nanocomposites, Silver (Ag) ions were added to blend. Ag particles has some unique characteristics increased optical, electromagnetic, and catalytic properties. The yield and electrical conductivity of the products (polymer) were investigated as physical characteristics. The electrical conductivities of Cs/PPy/Sep NC were determined by four point probe technique. In addition, the resulting NC were characterized with spectroscopic method that was Fourier Transform Infrared Spectroscopy (FTIR), and also morphological method, which was Scanning Electron Microscopy (SEM). According to conductivity results, Polypyrrole/Chitosan (PPy/CS) composite polymers showed conductivity between 1.8x10-6 and 1.4x10-2 S/cm. Polypyrrole-Chitosan/Sepiolite (Ppy-CS/Sep) nanocomposite polymers showed conductivity between 3.0x10-4 and 6.41x10-4 S/cm. Polypyrrole/AgNO3 nanocomposite polymers had a conductivity between 0.755 and 7.2 S/cm. According to SEM results, PPy/CS-1 sample has average size of 28.90 nm and PPy-CS/Sep-1 sample has average size of 28.63 nm. In future, many applications will benefit from conductive materials like PPy/CS, PPy-CS/Sep and PPy/Ag in biosensors, bioactuators and many other biomedical applications which will be very important in next century.