Understanding Addition Polymers and Their Applications
Properties and applications of addition polymers are fundamental concepts in organic chemistry that explain how simple molecules combine to form larger, more complex structures. Addition polymers begin with alkene monomers, which are molecules containing carbon-carbon double bonds. These double bonds can break open and join together in a chain reaction process called addition polymerization.
The formation of addition polymers starts with ethene monomers, which contain a carbon-carbon double bond. During polymerization, these double bonds break and allow the molecules to link together, forming long chains of repeating units. The resulting polymer chain has a non-polar backbone made entirely of carbon-carbon single bonds, making it chemically inert and resistant to many forms of degradation. This chemical stability is what makes addition polymers so valuable in various applications.
Definition: Addition polymers are long-chain molecules formed when many small molecules monomers join together through addition reactions, typically involving the opening of carbon-carbon double bonds.
One of the most important commercial addition polymers is polyvinyl chloride PVC, which is formed from chloroethene monomers. PVC has unique properties that make it particularly useful in construction and manufacturing. In its unmodified form, PVC is rigid and durable, making it ideal for applications like drain pipes and window frames. However, its properties can be modified through the use of plasticizers - chemical additives that increase flexibility by inserting themselves between polymer chains.
The physical properties of addition polymers depend largely on their molecular structure. Polymers with longer chains and fewer branches exhibit stronger intermolecular forces, resulting in materials that are both stronger and more rigid. This relationship between structure and properties allows chemists to design polymers with specific characteristics for particular applications. For example, plasticized PVC, which is more flexible than standard PVC, finds applications in clothing and flooring tiles.
Example: When ethene monomers C2H4 undergo addition polymerization, they form polyethene, commonly known as polyethylene. The process can be represented as:
nCH₂=CH₂ → −CH2−CH2−n
where n represents the number of repeating units in the polymer chain.