Giant molecules called polymers are made up by the bond of simpler molecules (monomer) by a polymeriztion reaction into essentially endless chain stuctures.
The basic starting material for modern synthetic plastics is ethene (ethylene), H2C=CH2. Ethene is itself a monomer which on heating (100-400 C)under hige pressure gives Polyethylene: 2nH2C=CH2 > (CH2-CH2-CH2-CH2)n
Polyethylene is a tough solid, somewhat soft and very resistant to chemical attack. Ployethylene can be blown into molds to make a wide variety of contaniers and other shapes.
I put this section in my website because even though plastic don't have a large role in running shoes they are there and do serve a purpose.
