ABSTRACT
In the previous chapter, we showed how the chemical structure of polymers influences their mechanical properties. The glass-transition temperature and the rate of cooling from the melt determine whether the polymer will be a hard, stiff material or a soft, flexible material. These qualitative differences can be quantified by measurement of standard mechanical properties. Students are generally introduced to the subject of mechanical behavior through the study of linear elastic metals that exhibit solid behavior at normal operating temperatures and conditions. However, this study reveals that polymers exhibit fluid as well as solid behavior and are viscoelastic and viscoplastic at room temperature. The mechanical properties of polymers are strain-rate sensitive and highly temperature dependent.
