What is the chemical composition of plastic?

Answer 1

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Plastic is made of monomers

Organic plastics are polymers, composed of monomers (repeating units). A polymer is a chain of molecules repeated again and again

You may ask, "Where do monomers come from?".

But to get an answer, you'll need to click on "What are the raw materials used to make plastic?" in the "related questions" section below.

Carbon and HydrogenDifferent kinds of monomers produce different kinds of plastics.

All organic plastics include a long backbone of carbon.

Some plastics, such as polystyrene, are composed of monomers that contain only carbon and hydrogen.

Other kinds of plastics are "functionalized" with a wide variety of other kinds of atoms either present in the original monomer, or added later after polymerization.

Most amino acids can be composed entirely from carbon, hydrogen, oxygen, and nitrogen (CHON).

All the other amino acids can be composed of CHON and sulfur.

"Plastic" is a term for a group of materials. Just like saying something is a "metal" doesn't tell you what type of metal or metal alloy it is, saying something is "plastic" doesn't tell you what kind of plastic or mixture of plastics it is made of. A plastic material can be any of a wide range of synthetic or semi-synthetic organic solids. Most plastics are "amorphous" solids although there are some that are crystalline. Plastics are usually a mixture long chain polymers. Although it is possible to get a narrow range of chain lengths or molecular weights, most plastics are defined in terms of the monomers that are polymerized to create them and then the range of molecular weights of the majority of the molecules making up the plastic is specified. Most plastics are made up of polymers of just one monomer, but sometimes blends will be used. Plastics can also contain other materials that modify their properties such as plasticizers. Many of them also contain residual amounts of the original reactants they were polymerized from and the solvents that the reactants were dissolved in. Consequently, most plastics have a distinct odor when they are new. Since cars contain a lot of plastics, that odor helps contribute to the "new car" smell.

Elementally, plastics can contain carbon (C), hydrogen (H), oxygen (O), but also nitrogen (N), chlorine (Cl), fluorine (F), silicon (Si), sulphur (S), and phosphorus (P). The term plastic merely refers to the property of being flexible but firm.