Effects Of Magnetic Field On Polymerization Of Aniline And Characterization

Polyaniline, the air stable-conducting polymer, can be synthesized both by electrochemical and chemical oxidative polymerization methods. The chemical oxidative polymerization process is particularly important since this synthesis is the most feasible route for the production of polyaniline on a large scale. The chemical oxidative polymerization of aniline has been well studied. By varying the polymerization conditions, it permits the production of polymers of different molecular weight and valuable properties, which potentially make it possible to use it as an electrode, antistatic, anticorrosion, electrochromic material in microelectronics for chemical and biosensors and so on.Magnetic effects can be technological interest because they offer a new way to perform radical processes. This is because through very weak perturbations of the magnetic field one can control the chemical kinetics and thus the course and rate of reactions that normally require much higher chemical energies. At the same time magnetic effects upon chemical processes provide useful methods for the elucidation of reaction mechanisms and techniques for controlling the reaction rates and product yields. Magnetokinetic effects registered in chemical radical processes developed in a magnetic field were justified after the discovery and understanding of nuclear and electronic spin polarization during the reactions. Polymerization processes that are directly dependent on the radicals and whose presence determines the subsequent evolution of reactions, will be consequently influenced by the existence of an external continuous magnetic field and can exhibit magnetokinetic effects.Polyaniline was obtained by chemical oxidation in the system of microemulsion and solution polymerization in magnetic field. The effect of magnetic field on the polymerization rate, molecular weights, conductivity, solubility, anticorrosion, the size of polyaniline were studied. The structure of polyaniline was characterized by IR and UV spectrum and the thermal degradation behavior was assessed using TAG techniques and crystallization was characterized by X-ray diffraction. The results show that the polymerization rate, molecular weights, conductivity, solubility, anticorrosion, crystallization, thermal stability enhance in the presence of magnetic filed and no effect of magnetic field on the basic structural units of polyaniline was observed; within the range of the intensity of magnetic field studied, the magnetic field of 0.4T exerts a great influence on polymerization of aniline.The effect of initiator dropping speed, the amount of emulsifier and initiator, concentration of proton acid and reaction time on yield and conductivity of polyaniline was studied in the magnetic field of 0.4T. By orthogonal experiments, a better synthetic direction for producing polyaniline was made as follows: the molar ratio of initiator to monomer, the weight ratio of emulsifier to monomer, concentration of proton acid, the reaction temperature and the reaction time are 0.9, 1.0, 0.35mol/L, room temperature and 3.5h, respectively.