ADDITION POLYMERS

Question 1

What are polymers? (1)

Answer 1

polymers are very large molecules that are built up from small molecules called monomers.

Question 2

what are addition polymers? (1)

Answer 2

are made from a monomer or monomers with a carbon-carbon double bond (alkenes). made from monomers based on ethene.

Question 3

what happens when monomers polymerise? (1)

Answer 3

the double bond opens and the monomers bond together to form a backbone of carbon atoms.

Question 4

what polymer is polythene made from? (1)

Answer 4

poly (ethene)

Question 5

what polymer is polypropylene made from? (1)

Answer 5

poly (propene)

Question 6

what polymer is PVC made from? (1)

Answer 6

poly (chloroethene)

Question 7

what polymer is acrylic made from? (1)

Answer 7

poly (propenenitrile)

Question 8

what polymer is polystyrene made from? (1)

Answer 8

poly (phenylethene)

Question 9

what does PVC stand for? (1)

Answer 9

polyvinyl-chloride

Question 10

what does acrylic stand for? (1)

Answer 10

acrilan, courtelle

Question 11

what are the uses of polythene? (2)

Answer 11

carrier bags, washing up bowls

Question 12

what are the uses of polypropylene? (2)

Answer 12

yoghurt containers, car bumpers

Question 13

what are the uses of PVC? (2)

Answer 13

aprons, ‘vinyl’ records

Question 14

what are the uses of acrylic? (1)

Answer 14

clothing fabrics

Question 15

what are the uses of polystyrene? (2)

Answer 15

packing materials, electrical insulation

Question 16

what are plasticisers? (1)

Answer 16

these are small molecules that get between the polymer chains forcing them apart and allowing them to slide across each other.

Question 17

how can the properties of polymers be modified? (1)

Answer 17

they can be considerably modified by the use of additives such as plasticisers.

Question 18

discuss the biodegradability of addition polymers. (2)

Answer 18

alkanes have a very strong non polar C-C and C-H bonds, they are very unreactive molecules, this does not mean that they are not attacked by biological agents (enzymes) and so they are not biodegradable

Question 19

what are the two types of poly(ethene)? (2)

Answer 19

low density poly(ethene)
high density poly(ethene)

Question 20

how is low density poly(ethene) made? (2)

Answer 20

made by polymerising ethene at high pressure and high temperature via a free-radical mechanism. This produces a polymer with a certain amount of chain branching.

Question 21

what are the properties of low density poly(ethene)?

Answer 21

-branched chains do not pack together well and the product is quite flexible, stretches well and has a fairly low destiny.

Question 22

what do the properties of low density poly(ethene) make it good for? (1)

Answer 22

these properties make it suitable for packaging (plastic bags), sheeting and insulation for electrical cables.

Question 23

how is high density poly(ethene) made? (2)

Answer 23

made at high temperatures ab pressure is a little greater than room conditions and uses a Ziegler-Natta catalyst.

Question 24

what is the product of a high density poly(ethene)? (1)

Answer 24

the results is a polymer much less chain branching.

Question 25

what are the properties of high density poly(ethene)? (1)

Answer 25

the chains can pack together well, this makes the density of the plastic greater and its melting temperature higher.

Question 26

what are the properties of high density poly(ethene) good for? (1)

Answer 26

milk crates, buckets and bottles.

Question 27

what are the types of recycling? (2)

Answer 27

-mechanical recycling
-feedstock recycling

Question 28

what is mechanical recycling? (2)

Answer 28

the first step is to separate the different types of plastics.
the plastics are then washed and once they are sorted they may be ground into small pellets, these can be melted and remoulded.

Question 29

what is feedstock recycling? (1)

Answer 29

the plastics are heated to a temperature that will break the polymer bonds and produce monomers, these can be used to make new plastics.

Question 30

what is the main limitation of recycling addition polymers? (2)

Answer 30

some polymers are thermoplastic polymers meaning that it will soften when heated however this can only be done a limited number of times because with each heating some of the chains break and become shorter thus degrading the plastics properties.