Investigation of electric and dielectric properties of chitosan based green superparamagnetic polymer nanocomposites

Abstract

In recent decades significant attention has been paid to the investigation and development of polymer nanocomposites (PNC s), with the objective of obtaining high performance smart materials. These polymeric nanocomposites have shown many attractive properties such as non corrosiveness, light weight, flexibility, higher breakdown strengths and tunable electric and magnetic properties. Recently, biopolymer based green PNC s have attracted great scientific interest due to their low cost, large availability and eco- friendly nature. The development of PNC s with a superparamagnetic property is highly useful for various applications such as in biomedical engineering. Superparamagnetism is a typical particle size effect exhibited by certain types of ferrimagnetic and ferromagneticn anoparticles reduced to below a certain size in which no hysteresis and magnetic remanence exists. Maghemite nanoparticles (and#1048650;-Fe2O3) exhibit the superparamagnetic behavior when its size is reduced to below 20 nm. Incorporation of maghemite nanoparticles into the chitosan matrix has led to formation of magnetic polymer nanocomposites. This thesis consists of synthesis of chitosan based superparamagnetic polymer nanocomposites and investigation of their electric and dielectric behavior. Green superparamagnetic polymer nanocomposites of chitosan containing maghemite nanoparticles have been prepared by solution casting method. Maghemite nanoparticles have been synthesized by co-precipitation method. The effect of temperature (30-150° C) and concentration (5-50wt%) of maghemite nanoparticles upon the electric and dielectric behaviour of the PNC s have been studied by using broadband dielectric spectroscopy. newline