Polymers are substances made of macromolecules formed by thousands of
atoms organized in one (homopolymers) or more (copolymers) groups that
repeat themselves to form linear or branched chains, or lattice
structures. The concept of polymer traces back to the years 1920's and
is one of the most significant ideas of last century. It has given great
impulse to indus- try but also to fundamental research, including life
sciences. Macromolecules are made of sm all molecules known as monomers.
The process that brings monomers into polymers is known as
polymerization. A fundamental contri- bution to the industrial
production of polymers, particularly polypropylene and polyethylene, is
due to the Nobel prize winners Giulio Natta and Karl Ziegler. The ideas
of Ziegler and Natta date back to 1954, and the process has been
improved continuously over the years, particularly concerning the design
and shaping of the catalysts. Chapter 1 (due to A. Fasano ) is devoted
to a review of some results concerning the modelling of the Ziegler-
Natta polymerization. The specific ex am pie is the production of
polypropilene. The process is extremely complex and all studies with
relevant mathematical contents are fairly recent, and several problems
are still open.