1. Polymer materials: general characteristics

It is important to understand the reasons behind the peculiar mechanical properties of polymers, especially when compared with those of simple organic molecules.

To achieve this, we need to consider the macromolecular nature of these compounds, i.e. the fact that a single molecular entity is made of a large number of constitutional repeat units, known as monomer units. In the case of homopolymers, monomer units originate from a single type of monomer molecules through a polymerization process. In the case of copolymers, the original monomer molecules are different.

Whereas simple organic molecules are generally made up of a few dozen atoms at most – as are monomer units –, polymers are macromolecules with a very large number of atoms (from a few thousand to infinity). The strength of such assemblies is due to the existence of highly energetic...