Type of thermoplastic in which three subtypes can be found: polyethylene, polypropylene, and pollyallomer. The two most common are polyethylene and polypropylene. In most cases, the analysis of polyolefin is performed at high temperature in high boiling solvents, but sometimes this is not feasible owing to the lack of complete solubility or swellability of the polymer, especially at high molecular masses and in crosslinked materials.