WM: Polymer Properties Flashcards
What do the physical properties of a polymer depend on?
Intermolecular bonds, and the structure of the polymer
What makes a thermoplastic soft and flexible? How long would the carbon chain be?
The ability of chains to slide over one another
The chain would be short, or branched
The longer the carbon chain….
The stronger the plastic, due to more intermolecular bonds forming
The shorter the carbon chain…
The weaker the plastic due to less intermolecular bonds forming
What is a Tm and what happens when you heat a plastic to above its Tm?
Tm is a thermoplastic’s melting point
It will soften and melt, intermolecular bonds are broken and the chains start to slide over each other
What is Tg and what happens if you cool a plastic to below its Tg?
Tg is the glass transition temperature of a plastic
Cooling the plastic will strengthen intermolecular bonds and it will become very rigid.
What happens when you try to bend a plastic that is below its Tg temperature?
The chains will not be able to slide over each other and the plastic will snap.
What is a crystalline polymer?
The arrangement of chains is ordered and they all run in the same direction.
What is an amorphous polymer?
The arrangement of chains is random and they all run in different directions.
Describe copolymerisation
Using a mixture of monomers and ending up with a polymer with lots of different properties
Why would you add a plasticiser to a polymer?
It makes it bendier by sitting between chains to push them apart, this reduces intermolecular forces
Describe cold-drawing
Pulling the chains so that they become more crystalline, more intermolecular bonds form and the plastic becomes stronger
