Modifications in Polymers Flashcards
Is it possible to produce a wide range of different polymers with properties which make them suited to a particular use?
Yes it is possible.
What can modifications do?
Modifications can also produce changes to the properties of polymers.
What does increasing the chain length mean?
It means that there’s more contact and therefore stronger forces between the molecules
What impact does this have?
It makes the plastic stronger
How are cross-links formed?
By atoms bonding between polymer molecules, so they can no longer move.
What impact does this have?
This makes a harder, stronger and stiffer material.
What is an example of cross-linking?
Vulcanisation, when sulfur atoms form cross-links between rubber molecules.
What is vulcanised rubber used to make?
Conveyer belts
Car tyres
What impact does adding plasticizers have?
Adding plasticizers makes a polymer softer and more flexible.
What is a plasticizer?
It is a small molecule that sits between molecules and forces the chains apart.
What impact does this have on the forces?
This means the forces between the chains are weaker, so molecules can more more easily.
What is plasticized PVC used in?
Children’s toys
What is unplasticized PVC (uPVC) used in?
Window frames
How else can a polymer be modified?
By packing molecules more closely together to form a crystalline polymer.
What does this do to the intermolecular forces?
It makes them slightly stronger.
