Compression, supramolecular organization and free radical polymerization of ethylene gas

At low pressure, ethylene gas consists of single translating and rotating molecules and behaves as an ideal gas. With decrease of free volume by compression, various rotating supramolecular particles are formed, which require less space for the movement: molecular pairs, bimolecules and oligomolecules. The appearance of a new kind of particles is manifested as a phase transition of the second or third order. An ideal gas consists of single translating and rotating molecules. α phase consists of rotating single molecules and rotating molecular pairs and it exists when the volume V is reduced to Vc <V<2Vc . (Vc is critical volume). β phase consists of molecular pairs and bimolecules and it exists when V<Vc and S>Sc . (Sc is critical entropy). γ phase and liquid ethylene consist of bimolecules and oligomolecules and they exist when S