Methods of Polymerisation — Definition
Definition
Imagine you have a lot of identical building blocks, like LEGO bricks. If you start connecting these individual bricks one by one, you'll eventually build a much larger structure. In chemistry, this is exactly what happens in polymerisation! The small, individual building blocks are called 'monomers' (from 'mono' meaning one, and 'meros' meaning part). When these monomers join together in a repetitive manner, they form a very large molecule called a 'polymer' (from 'poly' meaning many).
So, polymerisation is simply the process of linking many small monomer units to create a giant polymer chain. This linking isn't just a physical stacking; it involves actual chemical bonds forming between the monomers. Depending on how these bonds form, and whether any small molecules are lost during the process, we classify polymerisation into different methods.
Think of it this way: if you have many ethene molecules (), which are monomers, they can open up their double bonds and link end-to-end to form polyethylene, a common plastic. This is one type of polymerisation. Another type might involve two different types of monomers reacting, and during their reaction, a small molecule like water is removed. For example, a dicarboxylic acid and a diamine can react to form a polyamide (like nylon), releasing water molecules in the process.
The key idea is that polymers are macromolecules, meaning 'large molecules', and their properties (like strength, flexibility, melting point) are vastly different from the simple monomers they are made from. Understanding the 'methods' of polymerisation is about understanding the different chemical pathways and conditions under which these fascinating giant molecules are constructed, which is crucial for predicting their properties and designing new materials.