Synthetic Polymers Flashcards
Polymer
A large molecule made up of many smaller molecules (repeating subunits) called monomers
Addition Polymer
Formed by joining up many small molecules called monomers & only occur in monomers containing C=C bonds
Addition polymerisation
Addition reaction in which a large number of monomers join together to form a polymer
Factors needed for addition polymerisation
High pressure & use of a catalyst
Monomer
A molecule that can be bonded to other identical molecules to form a polymer
Use of poly(ethene)
Low density: LDPE, Polythene bags
High density: HDPE, Plastic bottles
Poly(propene)
Food containers (dishwasher safe) as melting point is very high compared to many other plastics (won’t cause dishware made from this plastic to warp)
Poly(chloroethene)
PVC (poly vinyl chloride), used for window/door frames, water pipes, electrical insulation
Poly(tetrafluoroethene)
PTFE/Teflon
- Coating for non-stick pans for cooking
- Bearings
- Circuit boards
- Medical uses
- Waterproof clothing
Issues with addition polymers
Many plastics non- biodegradable
Biodegradation
Disintegration or decomposition of materials by microorganisms into simpler substances
Non- biodegradable materials
Cannot be broken down by microorganisms into simpler substances
Why can’t addition polymers be broken down?
- Non- natural
- High energy required to break C-C single bonds
- No metabolic pathway available
- Pastics wastes can persist in the environment for centuries
Plastic pollution
- Land litter
- Kills marine animals by entanglement/ingestion
- Disrupts hormonal mechanisms
- Photodegradation of plastics releases toxins into the atmosphere
Substitution reaction
A reaction where an atom or group of atoms is replaced by a different atom or group of atoms
