Study On Properties And Preparation Of Magnetic Particles/Conducting Polymer Nanocomposites By High Energy Ball Milling

Composites of conducting polymers containing magnetic nanoparticles have attracted considerable attention because of their unique magnetic and electrical properties. They have many potential applications in electromagnetic interference shielding, electrochromic device, non-linear optical systems and microwave absorbers.Recently, a lot of researches on magnetic particle-conducting polymer composites have been reported. The mainly preparation methods are solution commixing method, sol-gel method, microemulsion method, self-assembling method and etc. High energy ball milling has been one of the important methods for the preparation of multi-system composites, which exhibit particular chemical and physical properties. But little work has been reported on the preparation of magnetic particle/conducting polymer nanocomposites by high energy ball milling. In this work, Fe₃O₄, Fe, α -Fe₂O₃ and conducting polyaniline(PAN) powders were selected as material to produce magnetic particle/conducting polymer nanocomposites by high energy ball milling. The components are investigated by Mossbauer Spectrometry, in addition, we use the technique of XRD, FTIR, VSM and network analysis to supplement the information. The morphology of the sample is measured by transmission electron microscopy (TEM) and scanning electron microscopy (SEM).Firstly, we study the Fe₃O₄/PAN system by high energy ball milling. It is found that after milling the crystallite size of Fe₃O₄ particles are rapidly reduced to nanosize. PAN reacts with Fe₃O₄, forming some paramagnetic phase and a small number of superparamagnetic α -Fe₂O₃ particles. A significant change is observed with the asymmetric broadening of Mossbauer spectrometry. And the components ot the A and B sites of Fe₃O₄ particles are distinctly transformed. The electric and magnetic properties of the composites are also changed. With milling 90 hours, the absorbing property seems to be the best.Secondly, we study the Fe/PAN system with milling at different atmosphere. Milled in air, Fe and PAN powders in the composites are all oxidated. Somesuperparamagnetic spinel particles are found and some FcOrlike products are formed on the surface of Fe. Milled in Ar2, Fe and PAN react to form interphase and some paramagnetic products. The electric and magnetic properties of the composites are also changed. With milling 70 hours in the air, the absorbing property seems to be the best.Then, we study the α -Fe2O;yPAN system. We find with the increasing of milling time some superparamagnetic α -FC2O3 particles are formed. 0 bonds on the surface of α -Fe2O3 are broken and connected with PAN chain, therefore some defected Fe particles are formed. The magnetic measure finds with the increasing of milling time the saturation magnetization and coercive force of the composites are increased, so that we can conclude there are really some magnetic products in the composite. The absorbing property of composite seems not to be improved but the obsorbing frequency is changed .