Time - Temperature - Stress The Equivalence Of Polymer Materials Research

As we know,it is one of the most important problem in the modern polymer science and engineering to predict and estimate the mechanical properties of polymers in a long term and/or in a very short interval. The WLF Equation had been used for a long time to solve the problem, even though it had certain limitation to describe material's behavior.In our paper, first of all, the same equation as WLF Equation in form will be derived by applying Doolittile Equation and Arrhenius E-quation,at the same time the clear and definite physical means of two parameters c₁ and c₂ will be also obtained and the cause of calculate error is to expose.Thus a new time-temperature equivalency equation is got from temperature-strain equation and a new concept about relaxation energy spectrum, its expression and a programm for representing the experimental data is also proposed.On the other hand ,it is considered that stress also has strong effects on physical-mechanical properties and processing properties besides time and temperature,so the equivalency among time-temperature-stress has been discussed and its relation equation will be studied. Many empirical equations often used in polymer science and engineering is also inferred by the relation.In the paper, it is shown the relation curve of deformation resistance-relaxation time (or observing time) of many typical polymer materials at the same stress and different temperature or at the same temperature and different stress. Thus the problem is solved that predict and estimate the mechanical properties of these typical polymers in a long term or in a very short interval under any conditions.