Addition polymerisation
A A large molecule formed from many identical smaller molecules known as monomers. is a substance of high The sum of the relative atomic masses of the atoms in a chemical formula., made up of small A part of a polymer that would make a complete polymer molecule if many of them were joined end to end..
Poly(ethene)
Poly(ethene) is a polymer made from a very large number of ethene A collection of two or more atoms held together by chemical bonds. combined together.
The reaction is called a Reaction in which monomer molecules combine together to form larger polymer molecules.:
- ethene is the Small molecule, usually containing a C=C bond, that can join end to end with other monomers to form a polymer molecule.
- poly(ethene) is the polymer
The C=C double bond in ethene is involved in the polymerisation reaction. It allows ethene molecules to join together to form a single A substance formed in a chemical reaction., so it is an example of an Type of reaction in which two substances react together to form one new substance.. Poly(ethene) is an Chemical reaction in which unsaturated monomers (small molecules) join together by addition reactions to produce a polymer (long molecule)..
Modelling addition polymers
It is too difficult to model a complete addition polymer molecule, as it contains many The smallest part of an element that can exist.. Instead, we show the structure of its repeating unit, the part that is repeated many times. To deduce the structure of a polymer from the monomer:
- Draw the structure of the monomer but use C–C instead of C=C.
- Draw brackets around the structure with a long bond passing through each one.
The table shows the structure of ethene and its polymer.
Modelling addition polymerisation
Equations use repeating units to model addition polymerisation reactions. The letter n stands for a large number.
Question
The diagram shows the structure of propene. Deduce the structure of poly(propene), and use this to show an equation for the polymerisation of propene.