Addition Polymerisation Flashcards
How do alkenes form polymerisation?
Addition polymerisation
What is an addition polymer?
Very long molecules made from many thousands of alkene monomer units joined together. The pi bond breaks, allowing monomer units to add together.
What should you never forget when drawing a repeat unit polymer?
That the end bonds stick through the brackets and that you add n to the bottom right
What are the benefits of polymers?
- Readily available
- Cheap to buy
- Convinient compared to alternatives like glass bottles, metal bins, paper bags and cardboard packaging
- Ideal for food and chemical storage due to lack of reactivity
What are the cons of polymers?
- Disposal of alkene based polymers causes environmental concerns as they are non-biodegradable
- Polymer industry has had to clean up its act recently due to increased pressure from government and society as a result of environmental concerns
What is the issue when dealing with waste polymers with chlorine ?
Recycling polymers with chlorine (eg PVC) releases HCL, a highly corrosive gas as well as toxic dioxins. This makes it hazardous
How do we deal with waste polymers?
- Not all polymers are easy to recycle. Made from fossil fuels so have high energy content. Most are burnt to recover the energy to produce heat for steam to generate electricity
- Feedstock recycling turns polymers back to og monomer. They’re then used as chemical feedstock (reactants/raw materials) for other chemical processes
What are the fututure uses and sources of polymers?
Lose reliance on making polymers from crude oil (finite source)
- Obtained from renewable and sustainable alternatives (bioplastics from plant cellulose, starch oils and proteins)
- Develop biodegradable and photodegradable plastics
- May contain OH groups to form H bonds with water and break down
- May contain additives like C–O which absorb light. Bods vibrate when light is absorbs, weakening polymer and starting the degradation.
