1. Polymers Polymerisation - Methods of sticking Mers together
The process of sticking mers together is called polymerisation. The two ways of doing this are;
1- Additional polymerisation, this is the most important of the two because most important polymers are made this way and,
2- Condensation polymerisation. This method tends to yield rigid plastics.

2. Polymers Addition Polymerisation
The basic idea of sticking mers together like this is similar to a zip. The mers are added onto the end of a growing chain. There are three basic parts to the process:
Initiation - Polyethylene C2H4, has a double bond between the carbon atoms. One of these bonds is stronger, while the other is weak. Each bond contains two electrons. The weak bond is attacked by a radical.

3. Polymers Addition Polymerisation
This radical grabs an electron and leaves one electron behind.
Propagation -When other ethylene molecules come near the ethylene radical they too are attacked and a mer is attached. The combined molecule is a growing chain radical. The process continues by adding other ethylene molecules in a similar fashion.

4. Polymers Addition Polymerisation
Termination - Possible stops to the growing chains could simply be running out of mers or radicals.

5. Polymers Condensation Polymerisation
This process depends on splicing rather than zipping.
The starting molecules are spliced or joined together with small molecules, like water, being condensed out of the reaction at the end of polymerisation.
The remaining structure is a comples 3D structure which is rigid and has a significant cross-linking feature.

6. Polymers Condensation PolymerisationH
C = O .
Formaldehyde OH
Phenol OH OH H C
+H2O

7. Polymers Types of Polymers
Thermoplastics:
These are thermosoftening polymers and make up about % of the bulk of polymers. They include;
High Density Polyethylene --HDPE
Low Density Polyethylene --LDPE
Poly Vinyl Chloride --PVC
Polystyrene -- PS
Polypropylene PP

8. Polymers Types of Polymers
Thermosetting:
The important ones in this group include;
Phenolics - This is a group of polymers based on phenol formaldehyde (PF) the original developed by bakeland. It is a cheap, brittle, muddy-brown (or black or blue) polymer.
Urea-formaldehyde - A white polymer that can be easily coloured. Uses include electric plugs, sockets, and other fittings.

9. Polymers Types of Polymers
Melamine-formaldehyde. This is harder, more scratch resistant and clearer. It can be found in ‘melaware’ and formica table tops
Polyesters - This is the resin used in fibreglass production.
Epoxies - This polymer is used in adhesives.
Polyurethanes - Are hard to classify as they can exist as hard glassy polymer or as a soft flexible sponge.

10. Polymers Additives for Polymers
Just as metals are alloyed to improve their properties, substances are added to polymers to improve theirs. A typical example is