These plastics are made by linking many monomers together into long chains with a carbon backbone. Polyethylene, polypropylene and polystyrene are the most common examples of these. Below is a diagram of polyethylene, the simplest plastic structure. Even though the basic makeup of many plastics is carbon and hydrogen, other elements can also be involved. Oxygen, chlorine, fluorine and nitrogen are also found in the molecular makeup of many plastics.
Nylon contains nitrogen.
Teflon contains fluorine. Polyester and polycarbonates contain oxygen. The majority of plastics are thermoplastic, meaning that once the plastic is formed it can be heated and reformed repeatedly. This property allows for easy processing and facilitates recycling. The other group, the thermosets, can not be remelted.