I'm a college freshman, so my knowing about chemistry is not much. I want to know exactly what a polymer is, how does it work, and how is it formed. Thanks!
Polymer is a large molecule made of repeating units that are called monomers; The process of joining together of repeat unit monomers is called polymerization. The word polymer is derived from Greek word Poly- which means many.
Polymers can be made by various methods such as condensation polymerization, free radical polymerization, addition polymerization, copolymerization etc.
What makes polymers fascinating is that various monomers can be used to engineer desired and unique properties in polymers such as heat resistance, tensile strength, high impact resistance, toughness , low surface tension etc. Most modern engineered materials utilize innovative polymers in vast areas of applications, and are developed by polymer chemists and polymer and material scientists.
Polymer Chemistry is a fascinating field.
A polymer is a large molecule made up of repeating structural units called monomers, which are bonded together in a long chain. Think of it like a train made of many identical or similar cars linked together.
Natural Polymers—Found in nature.
Examples:
Cellulose (in plants)
Proteins (chains of amino acids)
DNA (chain of nucleotides)
Natural rubber
Synthetic Polymers—Man-made, usually from petrochemicals.
Examples:
Polyethylene (used in plastic bags)
Polystyrene (used in foam products)
Nylon (used in fabrics)
Teflon (non-stick coating)
A specific charateristic of polymer chemistry is the selection of reactants that are able to polymerize:
Typically an organic reaction adds two reactants together resulting in two or more products of which one is of value and the others are waste. Normally this process stops after one cycle and no polymer is formed. The intersting question is now what reactant characteristic repeats the reaction on this intermediate product to form a larger molecular unity. It becomes clear that such reactants must have two or more reactive sites that are available to react with other reactants to form long chains.
This process can be visualized by adding two magnetized iron balls together resulting in a dimer with reactive N and S poles at the ends. Adding more iron balls to the mixture will inevitably form an ever increasing 'molecular' structure.
As for the type of reaction, any organic addition reaction with such bi-functional monomers could be a candidate for polymerization to make long chains or linear polymers. The addition of monofunctional reactants will terminate the process and is used to control the molecularweight of the product. On the otherhand tri and quadrifunctionals can be added to cause crosslinking offering many new opportunities for products in material science.