The Research On The Pyromagnetic Effect Of PVC Sheet With Defects

In recent years, in many fields the high polymer materials have been replacing metal materials, because of their low prices, rich resources, corrosion resistance and easily processing, etc. advantages, so that their effect on people's production and living becomes more and more greater. For examples, in the automobile industry the bearing and piston rings are made by PTFE composite material, because the PTFE molecule force is small and slip into the pieces easily, so we use this materials to solve some problems which are metal processing surface finish low, low wear resistance. In the building materials industry, glass fiber dipping PTFE membrane materials have some advantages that are dust-proof, consecrated themselves, deft, shock-proof, improving daylighting condition, so it always be used for multifunctional sports facilities and other large building roof and urban spatial development. But because of the polymer materials in processing preparation, transportation storage, service process may exist or form a slight defects (micro holes, micro crack, micro inclusion etc.). Such materials will evolve and develop defects by external environment and loads, and the damage and ultimately led to materials damage. Taking pretension deformation process as an example, because in the whole process of destruction, the distortion produced specimens of quantity of heat, the rheological damage fracture process area will produce temperature gradient field and accompanied by the electromagnetic field generated. This is pyromagnetic effect. In the whole process, pyromagnetic effect is to participate in the whole law of conservation of energy. If we want to make research of the pyromagnetic effect and the temperature field and the change rule of electromagnetic field in the whole tensile process systematically, we'll analyze from macroscopic phenomenological theory combined with microscopic molecular theory.Firstly, this paper starts by using the thermodynamics theory, electromagnetic field theory and rheological model theory, and by considering the principle of continuum mechanics, so the thermal equilibrium equation of the whole damaged or fractured region, temperature field equation and energy balance equation are obtained. Then this paper describes the production mechanism of pyromagnetic effect in theory respectively from the macro and micro aspects in the tensile fracture process. It is more important that we use the whole-region measuring system self-developed by ourselves for the high polymer pyromagnetic effect. We collect and measure the temperature field and the electromagnetic field generated by the polymer, which contain the same defects in different materials tensile rates and specimens which contain different defects under the same tensile rates in the whole process of tensile test to draw the general change rule of the emergence and development of pyromagnetic effect.This paper provides methods and approaches for the structure of polymer materials on-line monitoring and nondestructive diagnosis in the complex environment and provides new theoretical and experimental basis for the reasonable use and design new materials. It has important theoretical significance and application value for the life prediction of new materials, safe production and accident prevention.