Polyamides - Higher
Condensation polymer, such as nylon, made by reacting a dicarboxylic acid with a diamine. are condensation polymers. Like Condensation polymer made from two types of monomer, one with two –OH groups and one with two –COOH groups., polyamides are Long molecules (such as nylon, Kevlar or polyester) produced during condensation polymerisation.. Two products form during polymerisation:
- a A large molecule formed from many identical smaller molecules known as monomers.A collection of two or more atoms held together by chemical bonds.
- a small molecule, often water
Forming polyamides
A polyamide forms from two different Small molecule, usually containing a C=C bond, that can join end to end with other monomers to form a polymer molecule.:
- a ‘dicarboxylic acid’ which contains two carboxylic acid groups, -COOH
- a ‘diamine’ which contains two amino groups, -NH2
For example, nylon is a common polyamide used to make carpets and clothes.
Making nylon in the lab
Nylon can be made at room temperature in the lab using two solutions, A and B. As an example, two suitable solutions are:
- Solution B containing hexanedioyl chloride, which is like a dicarboxylic acid but contains two reactive -COCl groups instead of two -COOH groups
- Solution A containing hexane-1,6-diamine, which contains two NH2 groups
Whatever monomers are used, some Solution A is poured into a beaker or a A type of flat, circular dish with a lid.. Solution B is carefully poured on top to form a layer over Solution A. A thin layer of nylon forms where the two solutions meet. The nylon is pulled out with forceps and wound around a glass rod.
This is often called the ‘nylon rope experiment’ because nylon continues to form until one of the monomers is used up. Hydrogen chloride is formed instead of water. This is an acidic gas with a choking smell, so the reaction should be carried out in a well-ventilated lab or in a fume cupboard.
