Crude Oil: The Original Plastics Source
Where Does it Come From?
Let’s jump in our time machine and go back to where it all started. Crude oil is the result of millions of years of decaying plants and animals, along with layers of sand, silt, and rock. Heat and pressure from the layers transform the decay into crude oil. This process, as old as time, is a form of composting. The result is composed of a mixture of hydrocarbons – molecules made of atoms of hydrogen and carbon. These elements are found deep below the earth’s surface.
The crude oil is extracted from the earth and processed or refined by petroleum refineries. The process is known as distillation, which entails heating crude oil causing evaporation and condensation. At varying temperatures, the components of the oil separate. The resulting substances are known as fractions, consisting of various gases, solids, and liquids. Each of the fractions generated from the distillation process will end up as a polymer, each with diverse material properties depending on the mix of monomer molecules.
Prior to the refining process, crude oil is composed of hydrogens and carbons. These elements are molecules, as mentioned above. A molecule of one part is a monomer and monomers do not stick together. When monomers are put through a polymerization process, they become polymers, or molecules of many parts. Polymerization is the process of reacting the monomer molecules together by a chemical reaction. The resulting polymeric material becomes the raw material used to manufacture products.
From the point of the drilling, the crude oil is transported to be processed. Crude oil storage, along with storage of the various fractions, is an endeavor of gigantic proportions. These factors, as well as the drilling and distillation, are expensive and contain environmental concerns, such as emissions. It is from these concerns that the world of plastics has evolved and introduced recycling, advanced or chemical recycling and bioplastics.