Plastics are materials which are created by chemical conversion of natural products or in a synthetic manner from organic compounds. The main components are the elements carbon (C) and hydrogen (H). The bases of most plastics are carbon-hydrogen compounds, from which the single components of plastics, the so-called monomers, are produced.
1) Synthesis: production of a chemical compound from different elements or simple molecules. Synthesis is the opposite of analysis.
2) Organic media are pure non-metals of natural occurrence, e. g. petroleum, coal, wood, natural gas.
Inorganic media are compounds of metal and non-metals, e .g. minerals, ores etc.
3) Monomers are the basic molecules, i. e. the smallest components of which plastics are built.
Raw materials for the manufacture of plastics are natural compounds, such as cellulose, coal, petroleum and natural gas. In a refinery, petroleum is separated into several components by means of distillation.
Grouped into vaporisation ranges, gas, benzene, petroleum, gaseous oil, and as residue bitumen are obtained during distillation.
All components consist of hydrocarbons which only differ in size and form of the molecules. The most important component for plastics production is crude benzene.
In a heat cracking process this crude benzene is broken down into ethylene, propylene, butylene and other hydrocarbons and is then modified.