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C h e m g u i d e – q u e s t i o n s

4. This question is about PVC - poly(chloroethene). The following is taken from the Chemguide

page:

“

Because of the way the chlorine atoms stick out from the chain at random, and because of their

large size, it is difficult for the chains to lie close together. Poly(chloroethene) is mainly amorphous

with only small areas of crystallinity.”

a) What do you understand by the last sentence “Poly(chloroethene) is mainly amorphous with only

small areas of crystallinity.” ?

b) Despite the lack of crystallinity, PVC is quite hard and rigid. Explain the reason for that.

c) Varying amounts of plasticisers are added to PVC. Briefly, how do they work, and what effect do

they have on the properties of the PVC?

5. a) Write a simple equation to show the formation of poly(tetrafluoroethene) (PTFE) from its

monomer.

b) Describe the properties of PTFE which make it such a useful polymer. (No explanations are

needed.)

(I am not asking for explanations, because what – if anything – you will be expected to say may

well differ depending on your examiners. If PTFE is on your syllabus, it is essential that you look

at past papers and mark schemes to find out exactly what your examiners want.)

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