4(h) Synthetic Polymers Flashcards
Polymer
A large molecule made when many small molecules (monomers) join together.
Consists of many repeat units
Monomer
Small molecules that join up to make a polymer
Polymerisation
Joining of lots of small molecules (monomers) to form one big molecule (polymers)
Addition polymerisation
Molecules containing C=C (alkenes) break into a single bond, and the remaining electrons are used to join neighboring molecules
High temp. + pressures
Examples of Polymers
Ethene -> Poly(ethene)
Propene -> Poly(propene)
Chloroethene -> Poly(chloroethene)
Tetrafluoroethene -> Poly(tetrafluoroethene)
Chloroethene
One H in ethene replaced by Cl
Tetrafluoroethene
All H in ethene replaced by F
Problems in the disposal of Addition Polymers
- Contain strong covalent bonds -> makes them inert at ordinary temps
- Non - biodegradable -> Cannot be broken down by bacteria in the environment
Solutions to the problem of disposal of Addition Polymers
Bury them in landfill sites - will remain unchanged for years
Incineration (burning) - releases lots of energy that can be used for electricity generation
Advantages of Landfill for disposal of polymers
No greenhouse gases/toxic gases produced
Cheap
Disadvantages of Landfill for disposal of polymers
Ugly + smelly
Uses large areas of land
Waste will be there for thousands of years
Advantages of Incineration for disposal of Polymers
Requires little space
Can produce lots of heat for electricity generation
Disadvantages of Incineration for disposal of Polymers
Expensive to build + maintain
Produces greenhouse gases + toxic gases
Ash produced is disposed at landfill sites
Condensation Polymerisation
2 monomers combine and a water is lost
General equation for Condensation Polymerisation
Dicarboxylic acid + diol -> polyester + water
