Some Trends in the Mechanical Characterization of Polymers

Abstract

Because of the complex molecular mechanisms involved in the deformation of polymers, the variables of time and temperature assume much greater importance than they do in metals. An adequate description of the mechanical behavior of a polymer for engineering purposes must therefore include the effects of both these variables. Dynamic experiments, which have been used with such success by the physicist in the analysis of the structure of polymers, now hold out the promise of becoming a useful tool for the engineer. The results of such experiments may be expressed in terms of curves of storage and loss moduli as functions of time (frequency) and temperature, and a number of interesting ways have been proposed in which the engineer can use these curves. Studies are underway, both in Europe and America, aimed at reducing experimental difficulties and setting up standard test procedures. At the same time progress is also being made in the improvement of the more conventional types of tests.