1. Mass-market polymers

The crude oil refining diagram (figure 1 ) shows that during steam cracking, the naphtha from atmospheric distillation and the heavy products from vacuum distillation are taken together to produce :

• ethylene, the monomer of polyethylene ;

• propylene, the monomer of polypropylene ;

• benzene, a polystyrene monomer.

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

Table 1 completes this diagram, showing that, whatever the origin of the raw materials (coal, gas, oil), we pass through the phase of "large intermediates" to end up with the finished...