Addition Polymers Flashcards
What is a polymer
Very large molecules that are build up of small molecules
What is the name of the small repeating molecules that create polymers
Monomers
What happens when monomers polymerise
The double bonds open up and form a backbone of carbon atoms
How can monomers be represented
As a single bonded carbon pair with alkyl groups bonded. It is the surrounded by square brackets and a small n in the bottom right corner
How can monomers be identified in polymers
By finding a repeating pattern in the carbon chain
How do engineers alter properties of polymers
They add plasticisers
How do plasticisers work
They are molecules that get in between chain polymers spreading them apart changing the density
Why are most polymers not biodegradable
As they have strong non polar C—C bonds which can’t be broken down by enzymes and they are very unreactive
What is HDPE
High density poly(ethene)
What is LDPE
Low density Poly(ethene)
What is the monomer of HDPE and LDPE
Ethene
How is HDPE produced
temps slightly above room temp
pressure slightly above room conditions Ziegler-natta catalyst.
Causes chains to be close together making it stronger and harder to melt
How is LDPE made
High temperature
High pressure
Free radical substitution
Makes it have some branching and and not pack well making it flexible and stretchy
What is the solution to pollution by plastics
Reduce
Reuse
Recycle
2 ways of recycling polymers
Mechanical
Feedstock
How does mechanical recycling work
Separate types of plastic
Wash plastic
Cut down plastic into pellets
Melt plastic into new item
How does feedstock recycling work
Blast plastic until monomers reform from polymers
Use these monomers to form new polymers
Issue with feedstock recycling
The heat can break monomers so this process can only be used a certain amount of times
Issue with mechanical recycling
The time and effort required for the process
