Physical and thermomechanical behavior of plastics

This article looks at the general thermomechanical behavior of plastics, attempting as far as possible to give a synthetic view based on a classification based on their structure and the bonding forces that ensure their cohesion.

It also covers physical properties, with the exception of electrical and thermo-optical properties dealt with in articles [A 3 140] and [A 3 145] respectively, changes in properties due to physical ageing [A 3 150] or chemical ageing [A 3 151] , the action of water , or friction and wear [A 3 139] .

Certain aspects directly related to these properties are also the subject of other articles, such as standardized tests (see Standardized tests section of this treatise) or crack propagation in dynamic fatigue [A 3 136] .

Plastics are viscoelastic materials and, more often than not, complex mixtures. This article will focus on pure resins. Some additives, as we shall see later, have little direct influence on mechanical properties, and all are the subject of their own articles (see the Additives and Reinforcements for Plastics section of this treatise).