Polymers Flashcards
What are individual tangled chains of polymers held together by?
Weak intermolecular forces which are free to slide over each other
What do thermosoftening polymers not have?
Cross linking between chains
Why is it easy to melt thermosoftening plastics?
The forces between the chains are easy to ovevercome
What happens when thermosoftening plastics cool?
They harden into a new shape
Can you remould thermosoftening polymers?
Yes , as many times as you like
What are strong intermolecular forces known as?
Cross links , holding chains firmly together
Thermosetting polymers have what?
Crosslinks
How do croslinks hold the chain together?
In a solid structure
Thermosetting polymers have what properties?
Strong , hard and rigid
How is low density ( LD ) polythene made?
By heating Ethene to 200 degrees under high pressure
What is low density polythene used for?
Bags and bottles due to its flexible property
What effects the properties of polymer?
The starting material and reaction conditions
How is high density polythene (HD) made?
At a lower temperature and pressure ( with a catalyst )
What is high density polythene used for?
Water tanks and drainpipes due to its rigid properties
Properties of plastics are determined by what?
Forces between molecules
