Chemistry · Both
Polymers
How addition polymers form from alkenes, representing polymers, properties and environmental issues.
Polymers are long-chain molecules made by joining many small monomers. Many plastics are addition polymers made from alkenes.
Addition polymerisation
Alkene monomers (C=C) open the double bond and join in a long chain.
No other product is formed (addition).
Examples: poly(ethene) from ethene; poly(propene) from propene.
Drawn with a repeating unit in brackets with an n.
Properties and uses
Depend on chain length and branching:
• Strong intermolecular forces → higher melting point, more rigid
• Uses: packaging, pipes, fibres, insulation
Many are non-biodegradable → landfill and pollution issues.
Recycling and developing biodegradable polymers are important responses.
Practice questions
Try these without looking at the answers first.
Q1.What type of monomer makes addition polymers?
Show answer
Alkenes (with C=C)
Q2.Name the polymer from ethene.
Show answer
Poly(ethene)
Q3.Why are many plastics an environmental problem?
Show answer
Non-biodegradable / pollution / landfill