Addition polymers Flashcards
Polymers are large molecules made from many…
Monomers
What are addition polymers made from?
Monomers based on ethene.
Draw the general formula for an addition polymer monomer.
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How do ethene monomers form an addition polymer?
Their carbon to carbon double bonds break and the monomers form together to form a backbone of carbon atoms.
How would the formation of an addition polymer be shown as a formula?
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What does many ethene molecules polymerise to form?
poly(ethene)
What does many phenylethene polymerise to form?
Poly(phenylethene)
What is another name for phenylethene?
Styrene
What is another name for poly(phenylethene)
Polystyrene
What is poly(ethene) typically used for?
Carrier bags and washing up bowls
What is the common name for poly(ethene)?
Polythene
What is the common name for poly(propene)?
Polypropylene
What is poly(propene) typically used for?
Yoghart containers and car bumpers
What is the common name for poly(chloroethene)?
PVC (polyvinylchloride)
What is poly(chloroethene) typically used for?
Aprons, vinyl records and drainpipes
What is the common name for poly(propenenitrile)?
Acrylic
What is poly(propenenitrile) typically used for?
Clothing fabrics
What is the typical use for poly(phenylethene)?
Packaging and electrical insulation
What are plasticisers?
Small molecules that can modify polymers
How do plasticisers modify polymers?
They get between the polymer chains and force them apart. This allows them to slide across each other (making them more flexible)
Why are polyalkenes not biodegradable?
They have strong, non-polar C-C and C-H bonds and so they are very unreactive molecules and are not attacked by biological agents, such as enzymes.
How do you create low density poly(ethene)
Polymerising ethene via free-radical reactions at high pressure and high temperature.
Low desity poly(ethene) has rather a lot of chain branching due to the random nature of free radical reactions. What affect does this have on the properties of low density(polyehtene)?
The branched chains do not pack together well and so it is quite flexible, stretches well and has low density.
What are the typical used for low density poly(ethene)?
Plastic bags, sheeting and insulation for electrical cables
How is high density poly(ethene) made?
At high temperatures and pressure little greater than room conditions and with the aid of a Ziegler-Natta catalyst.
High density poly(ethene) has little chain branching. How does this affect the properties of high density poly(ethene)?
The chains are able to pack together well and so the density if the plastic is greater and it’s meting point higher.
What are the typical used of high density poly(ethene)?
Milk crates, buckets and bottles
How could we reduce the amount of plastics being sent to landfills?
Reuse or recycle the plastics
What are the two different types of recycling?
Mechanical and feedstock
What is the process of mechanical recycling?
The different types of plastics are separated and wash them. They are then ground up into small pellets and melted and remoulded.
What is the process of feedstock recycling?
The plastics are heated to a temperature that will break the polymer bonds ad produce monomers. The monomers are then used to make new plastics.
What is the problem with recycling plastics?
Some plastics can only be heated up a certain amount of times because after each time it is heated it changes shape (some of the chains break and become shorter). This degrades the plastics properties.
