1. Widespread polymers

The crude oil refining flowchart (Figure 1 ) shows that during steam cracking, naphtha from atmospheric distillation and heavy products from vacuum distillation are used to ultimately produce:

• ethylene, a monomer of polyethylene;

• propylene, a monomer of polypropylene;

• benzene, a monomer of polystyrene.

These three materials are by far the most widely used in the packaging industry.

The table at 1 complements this diagram by showing that, regardless of the origin of the raw materials (coal, gas, oil), the process goes through the "major intermediates"...