The polypropylene (or polypropene abbreviated as PP) is a thermoplastic polymer which shows different versatility. The most interesting product from the commercial point of view is the one isotactic: it is a semi-crystalline polymer featured by a high breaking load, a low density, good thermal and abrasion resistance.

The density of the isotactic polypropylene is 900 kg/ m3 , and the melting point is often over the 165° C.

The chemical properties affected in the production phasis, include the stereoregularity, molecular mass and the polydispersion index. The atactic product presents itself like a rubbery material and has a poor commercial interest (it was only used as an additive).