2. Properties and features

2.1 Mechanical resistance

Polymers come in two forms:

• the amorphous form;

• semi-crystalline form.

Coloring amorphous polymers: this does not generally pose any problems in terms of mechanical strength. The pigment molecules are trapped in the macromolecular network without modifying it.

Coloration of crystalline polymers: when polymers are semi-crystalline, two cases can occur:

• the colouring is based solely on mineral pigments; in this case, there should be no major problem since the pigments are also crystalline;

• coloring is carried out with organic pigments; the...