2.5 The Properties Of Polymers Flashcards
What is poly(propene) made of?
Propene
Which softens at a higher temp, poly(propene) or poly(ethane)?
Poly(propene)
What conditions are used to make low density poly(ethane)?
- high temperature
* high pressure
What conditions are used to make high density poly(ethane)?
- low temperature
* low pressure
What do the properties of polymers depend on?
The monomers used to make it and the conditions used to carry out the reaction
Which has a higher softening temperature and is stronger, hd poly(ethane) or Ld poly(ethane)?
Hd poly(ethane)
Who do LD and HD poly(ethane) have different properties?
They are made under different conditions
What is a thermosoftening polymer?
Polymer chains that are tangled together
Give an example of a thermosoftening polymer
Poly(ethane)
What happens when thermosoftening polymers are heated and then cooled again? What does this mean?
When they are heated then become soft and when they are cooled they harden again. This means it can be moulded many times to get a desired shape
What are thermosetting polymers?
Strong covalently bonded polymers with cross links between their polymer chains
How do we change the shape of thermosetting polymers?
Trick question, we can’t because they don’t melt or soften when we heat them
How are the thermosetting polymers held in place?
Strong covalent bonds hold the polymer chains and there are cross links between them too
What is the main difference in the structures of thermosoftening and thermosetting polymers?
Thermosoftening polymers have no cross links or no covalent bonds between the polymers
Why do thermosoftening polymers change shape when they are heated?
The have weak force between the chains so when heat is applied the weak intermolecular forces are broken and the polymer becomes soft
