الفهرس 
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Abstract
Polypyrrole conducting polymers have become significant in different biomedical applications, but unfortunately, they are insoluble with poor mechanical properties. A natural soluble polymer as chitosan can be used to improve such properties. CHI/PPy blends were synthesized by dispersing the different doped amount of polypyrrole into the chitosan matrix. The physical properties of the synthesized composite films were investigated by X-ray diffraction and FTIR, and UV/Vis. spectroscopy. XRD illustrated the semi-crystalline nature of chitosan and the amorphous properties of the CHI/PPy blend. FTIR of analysed samples showed the characteristic peaks and the electrostatic interaction between the two polymers. UV/Vis analysis implied that the optical band gap of composite films decreases with increasing polypyrrole concentration, which can be assumed to increase the electrical conduction in the composite films. Scanning electron microscopy (SEM) indicated that the morphology of the chitosan in the blend was affected by the addition of PPy. The AC conductivity was also measured for chitosan pure and the CHI/PPy blend. The dielectric constant, ε’, explained that the blend undergoes higher dissociation with increasing temperature. The dielectric modulus, M’, indicated that the dispersion frequency increases with temperature. The loss tangent, tan δ, attributed to the decrease of resistivity of the blend, due to the increase in the number of charge carriers available for the ionic conduction. The impedance, Z’, caused the conductivity to occur by the increase in ionic mobility, which is concerned with the increase in the number of mobile charge carriers and segmental mobility. The swelling test was measured to test the ability of the blend to swells, and its pH dependence. Antibacterial test was tested to investigate the inhibition zone according to the type of bacteria and blend concentration. And the evaluation of the activity index %.