The different states of polymers based on their thermomechanical properties

The different transition points which characterize eventually the three solid, plasto‐elastic and rubbery states have been determined by several methods. The authors show nevertheless that good data can be obtained using very simple traction experiments, at different temperatures. These experiments were carried out in different conditions of mechanical strain and temperature; the corresponding characteristics of breaking load and flow strain were noticed. Thus thermomechanical diagrams were obtained, either of the breaking load either flow strain, in function of the temperature for the most important classes of polymers: thermoset, thermoplastics, including crystalline linear and regular polymers, linear irregular polymers and crosslinked polymers. These diagrams give an indication on the limiting strains from which the use must be excluded taking into account flow straining at a given temperature. These diagrams make also more precise the transition points determined at given mechanical strains, of which the effect is important on the temperature where they occur. It is interesting to notice the increasing thermosensitivity of the method for the multibranched, crosslinked, irregular and regular polymers.