Polymers

Question 1

Monomers

Answer 1

Small identical molecules used to make polymers. Always alkenes.

Question 2

Mono means…

Answer 2

one.

Question 3

Poly means…

Answer 3

many.

Question 4

Polymers have…

Answer 4

a single bond.

Question 5

Poly(ethene)

Answer 5

Ethene molecule turned to a polymer. It is very useful plastic as it is easy to shape, strong and transparent. Used for plastic bags, some drink bottles…

Question 6

Polymers are used to make…

Answer 6

plastics.

Question 7

Ethene

Answer 7

Is the smallest unsaturated hydrocarbon molecule.

C2H4

Question 8

Poly(propene)

Answer 8

Forms very tough plastic. Used to make carpets, milk crates and ropes.

Question 9

Propene formula

Answer 9

C3H6

Question 10

Polymerisation

Answer 10

A reaction of monomers to make a polymer. The double bond opens.

Question 11

How to draw a repeating unit of polymer?

Answer 11

1. Pick up two carbon atoms next to each other
2. Draw the unit of two carbons
3. Put it inside a bracket
4. Extend the bonds from carbon to left and write, outside the bracket
5. Put n indicating a large number

Question 12

The properties of polymers depend on:

Answer 12

• the monomers used to make it

- the conditions are chosen to carry out the reaction

Question 13

Two types of poly(ethene)

Answer 13

-High density (HD) or HDPE
-Low density (LD) or LDPE
Both are formed from same monomers but made under different conditions.

Question 14

LD polyethene

Answer 14

Using very high pressure and a trace of oxygen. This causes that polymer chains are randomly branched and they cannot pack closely, so it has a lower density.

Question 15

HD polyethene

Answer 15

Using a catalyst at 50 degrees and slightly raised pressure. This produces straighter chains, which can pack more closely together, so it has a higher density. It has also a higher softening temperature and it is stronger than LD.

Question 16

Thermosoftening

Answer 16

Made up of individual polymer chains that are tangled together. These will soften very easily because the intermolecular forces between polymer chains are weak.

Question 17

When thermosoftening polymer cools down…

Answer 17

the intermolecular forces bring the polymer molecule back together and the polymer hardens.

Question 18

A thermosoftening polymer can be…

Answer 18

remoulded.

Question 19

Thermosetting polymers

Answer 19

These have strong covalent bonds forming cross-links between their polymer chains. It does not melt when heated.

Question 20

In thermosetting, the covalent bonds between polymer chains are made…

Answer 20

when they are first heated in order to shape them. These bonds are strong, stopping the polymer from softening. If heated strongly, the polymer will not soften but char.

Question 21

Development of polymers to:

Answer 21

• new softer linings for denatures (false teeth)
• new packaging materials
• implants that can slowly release drugs into a patient

Question 22

Light sensitive plasters

Answer 22

Uses light-sensitive polymer. If it is exposed to light, it will become less sticky and easily removable.

Question 23

Hydrogels

Answer 23

Polymers with a few cross-linking units between chains. This makes a matrix that can trap a water. These gels can be used as a wound dressing, allowing the body to heal in moist and sterile conditions.

Question 24

Smart polymer

Answer 24

Changes in a response to changes in its surroundings. E.g. light, temperature or other changes.

Question 25

Shape memory polymer

Answer 25

Makes stitching in difficult places easier. The temperature of the body makes the thread tighten and close the wound, applying the right amount of force.

Question 26

The PET from…

Answer 26

plastic bottles are used to make polyester fibres for clothing.

Question 27

PET

Answer 27

Very light and strong at the same time. Can be made transparent. Therefore, it is suitable for plastic bottles.