Chapter 13.5 - Polymerisation in alkenes Flashcards
What is a polymer?
A large molecule formed from many thousands of repeat units of smaller molecules known as monomers
What molecules undergo addition polymerisation to form long saturated chains?
Unsaturated alkene molecules
What are the conditions needed for industrial polymer making?
1) High temperature
2) High pressure
3) Catalyst
Draw the general equation for an addition polymerisation reaction
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What are some uses of poly(ethene)?
1) Supermarket bags
2) Shampoo bottles
What are some uses of poly(chloroethene)?
1) Pipes
2) Films
3) Insulation
What are some uses of poly(propene)?
1) Children toys
2) Packing crates
What are some uses of poly(phenylethene/styrene)?
1) Packaging material
2) Food trays
What are some uses of poly(tetrafluoroethene)? PTFE
1) Coating for non-stick pans
2) Cable insulation
Why are polymers used?
- Readily available
- Cheap to purchase
- Convenient
- Lack of reactivity
What does it mean if alkene polymers are non-biodegradable and how does it effect the environment?
- Cannot be decomposed by microorganisms
- Polymer waste kills marine life
How are polymers recycled?
- Discarded polymers are sorted by type
- They are copped into flakes, washed, dried, and melted
- Cut into pellets and used by manufacturers to make new products
Why can we not dispose and recycle PVC?
- Disposal and recycling of PVC is hazardous due to the high chlorine content and the range of additives
- When burnt, they release hydrogen chloride, a corrosive gas
How do we recycle PVC?
- Solvents dissolve the polymer
- High grade PVC is recovered by precipitation from the solvent
- Solvent is reused
How do we use waste polymers as fuels?
1) Waste polymers are incinerated to produce heat
2) Generating steam to drive a turbine, producing electricity/energy
What is feedstock recycling?
The chemical and thermal processes that reclaim monomers, gases or oils from waste polymers
- Materials can be used as raw materials for the production of new polymers
What is an advantage of feedstock recycling?
It is able to handle unsorted and unwashed polymers
What are alternatives to polymers?
1) Biodegradable
2)Photodegradable
What are biodegradable polymers?
Polymers that are broken down by microorganisms into water, carbon dioxide, and biological compounds over time
What are photodegradable polymers?
Polymers that contain bonds that are weakened by absorbing light to start the degradation
- Light-absorbing additives are used alternatively
