Abstract
It is well known that the mechanical behavior of polymers shows remarkable time and temperature dependences, that is, viscoelastic properties, as recognized in their creep and relaxation. This might come from their microstructures which have much different characteristics from those of metallic materials. Therefore, analyses of stress and strain in the viscoelastic body should be carried out based on the so-called viscoelasticity, but not on the elasticity.
The mechanical behaviors of elastic body are specified by elastic constants like Young's modulus, while those of viscoelastic ones are determined by several coefficients characterized by the function of time and temperature.
In this descriptive paper, qualitative explanations of mechanical properties, particularly time and temperature dependent properties, of polymericmaterials are made in relation to their molecular structures, then the fundamental concept on viscoelastic analysis is briefly introduced.
