Addition Polymers

Question 1

What are Polymers ?

Answer 1

a large molecule formed from many monomers bonded together in a regular repeating pattern

Question 2

What are addition polymers formed from ?

Answer 2

alkenes and substituted alkenes

Question 3

What is the name of the polymer made from ethene ?

Answer 3

Poly(ethene)

Question 4

Why are plasticisers added to some polymers ?

Answer 4

to make them more flexible because they do not have a c=c double bond they are unreactive

Question 5

What are the two forms of Poly(ethene)?

Answer 5

Low density polyethene

High density polyethene

Question 6

What is LDPE used for ?

Answer 6

more flexible so used for plastic bags and some plastic bottles; highly branched so chains do not pack closely together

Question 7

What is HDPE used for ?

Answer 7

less flexible, so used for kitchen ware ; manufactured using a catalyst; less branched so chains can pack more closely together

Question 8

What is the recycling code of Polythene ?

Answer 8

PE

Question 9

What is Poly(propene) used for ?

Answer 9

Food packaging, clothing , ropes and carpets. It is stronger than poly(ethene)

Recycling code: PP

Question 10

What is the other name for Poly(chloroethene) ?

Answer 10

Polyvinyl chloride (PVC)

Question 11

What are the uses of PVC ?

Answer 11

does not contain a plasticiser, so it is rigid and waterproof. It is used in water pipes, window frames, credit cards.

Question 12

uPVC contains a plasticiser. What does this mean it can be used for ?

Answer 12

contains a plasticiser so is more flexible.
It is used for waterproof clothing and electrical wire insulation

Question 13

What is the other name for Poly(phenylethene) ?

Answer 13

polystyrene

Question 14

What are the two different forms of Poly(phenylethene) ?

Answer 14

Expanded form
Unexpanded form

Question 15

What is the expanded form of Polystyrene used for ?

Answer 15

used an insulator- coffee cups, fast-food containers, house insulation

Question 16

What is the unexpanded form of Polystyrene used for ?

Answer 16

used for toys and containers

Question 17

What is the recycling code of Poly(phenylethene) ?

Answer 17

PS

Question 18

What is the other name for Poly(tetrafluoroethene) ? What are its uses ?

Answer 18

Teflon
it is used as a non-stick surface and anti-stain coating

Question 19

Atoms in the polymer molecule are bonded together by what ?

Answer 19

strong covalent bonds

Question 20

What are the intermolecular forces that are always between polymer chains ?

Answer 20

van der waals forces

Question 21

When melting polymers what must be overcome ?

Answer 21

the intermolecular forces between chains- covalent bonds are not broken

Question 22

What determines a polymers melting point ?

Answer 22

the stronger the intermolecular forces between the polymer chains, the more energy is needed to overcome them and the higher the polymers melting point

Question 23

Explain why a sample of solid polymer will melt gradually over a range of temperatures

Answer 23

The polymer chains making up a sample of solid polymer are all different lengths, so the van der Waals forces between them are of variable strength.

Question 24

Why are the melting points of branched polymers lower than that of straight chain polymers ?

Answer 24

Polymer chains with many branches cannot pack as closely together as straight chain polymers
Therefore van der waals forces are weaker, and melting points are lower
Branched chain polymers tend to be weaker and softer

Question 25

Why are melting points of polymer chains with few branches higher than branched polymers ?

Answer 25

polymer chains with few branches can pack together very efficiently resulting in stronger van der waals forces.
melting points are higher and the polymers tend to be stronger and harder (e.g HDPE)