Research On Non-linear Rheology And Temperature Effect Of The Engineering Polymers

The inherent defect evolving unceasingly cause the fracture of material, moreover evolution surmounts the different levels from microscopic to macroscopic, which can forms the multi-level system. Even if the level is identical, the defect evolution rule has the different forms because of the influences of material nature, the different load function or other factors. Therefore, the defect evolutionary process is complex in a multi-level system.Material deformation accompanied by the form of energy conversion and temperature changes. Especially in the deformation speed, and the distortions of the local deformation, the temperature change will be very obvious. Such deformation effects at high strain rate, change the role of the load and crackle rapid expansion process is more prominent. Its insulation heat can make materials reach the level of serious soften and fail. On the other hand, we can make use of materials deform for a measurement to thermal stress or deformation of the material .Therefore, research to material deformation process heat dissipated, especially sensitive to temperature, is of great significance.The paper studies the thermal production caused by the irreversible distortion in the defect high polymer material deformation process. In the thesis, deformation induced heating and crazing in polymers are considered theoretically and experimentally. The achievements and conclusions are listed as follows:(1) Base on the viscoelastic mechanism of polymer depend on time, single axes stretching experiments are proceeded to research viscoelastic distortion of high polymer with the dependence on non-linearity and stress. We get each material parameter by dealing with the data of experiments, and contrast several theories of one dimension creep.(2) The recent advances in experimental and theoretical research on thermo mechanical coupling effect in defect polymers were briefly reviewed.(3) In the paper, it analyzed the stress-strain zone nearby the defects in the case of tension for the theological material containing defects.(4) Under controlling the displacement speed, we observed temperature along with time change near the defect zone so as to obtain the isothermal about temperature along with time change and study the energy aerodynamic in the defect—evolution process.(5) The temperature change during deformation of polymers with defects was studied. A new analysis and explanation to the cooling phenomenon during elastic deformation of polymers was given.(6) According to the law of thermodynamic and experimental research, we obtain the energy production rate expression, the equation of temperature—risen and the computation expression about deformation heat of formation.The paper is subsidized by the National Natural Science Foundation of China(NSFC-10372074) .