polymerisation of alkenes

Question 1

what is a polymer

Answer 1

a molecule consisting of long chains of atoms

made up of a huge number of monomers joined together.

Question 2

alkenes undergo?

Answer 2

a reaction called addition polymerisation to form polyalkenes (do not contain C=C bond)

Question 3

why do polymers melt over a range of temperatures?

Answer 3

because it contains billions of polymer chains of all different lengths.- so the structure of monomers can be represented using repeating units.

Question 4

1st condition for polymerisation

Answer 4

3000 atm, 250’

Question 5

2nd condition for polymerisation

Answer 5

titanium (III) chloride, room temperature

Question 6

the widespread uses of polymers

Answer 6

carrier bags, plastic

-ropes, carpets

Question 7

PVC

Answer 7

• Used fro vinyl and electrical insulation

- releases toxic fumes of HCL when burned

Question 8

polymers are very

Answer 8

unreactive.

but also non-biodegradable

Question 9

the combustion of waste polymers

Answer 9

chains are so long that huge amounts of oxygen is needed for complete combustion.

-this isnt available so normal burning produces toxic gaseous mixtures containing CO and unburned hydroC

Question 10

making biodegradable polymers

Answer 10

biodegradable polymers- ones that naturally decompose.
-decompose very quickly in certain conditions- because organisms digest them.

-can be produced from raw materials or oil fractions

Question 11

how are chemists attempting to reduce problems related to disposal of alkenes.

Answer 11

• designing specialist incinerators which use heat produced by combustion to produce electricity.
• using catalytic cracking to break polymers down into short chain alkanes and alkenes, creates feedstock chemicals to make larger molecues
• designing biodegradable polymers (break naturally)