Polymers

Question 1

What are the two types of polymers?

Answer 1

addition and condensation

Question 2

What molecules undergo addition polymerisation?

Answer 2

alkenes

Question 3

What is special about addition polymerisation?

Answer 3

no waste products formed

Question 4

How are addition polymers formed?

Answer 4

via a free radical mechanism

Question 5

What is a common free radical initiator?

Answer 5

peroxide

Question 6

Why are addition polymers chemically unreactive and why is this useful?

Answer 6

c-c bonds are non-polar, useful as they cannot be attacked by acids/alkali/oxidising agents

Question 7

How would you represent the repeating unit of an addition polymer?

Answer 7

no brackets, but no double bonds, just the polymer structure without any brackets

Question 8

How is the polymerisation of ethene represented?

Answer 8

…………………………..H H
n H2C=CH2 —-> -(-C–C-)- n
H H

Question 9

Poly(ethene) use?

Answer 9

plastic bags

Question 10

Poly(propene) use?

Answer 10

pipes

Question 11

Poly(chloroethene) (PVC) use?

Answer 11

records

Question 12

Poly(styrene) use?

Answer 12

packaging

Question 13

Teflon use?

Answer 13

non-stick pans

Question 14

What are the options for solving the problem of polymers in landfill, and their problems?

Answer 14

-use biodegradable polymers - expensive
-incinerate them (can also be used to recover energy) - produces greenhouse gases and toxic gases
-recycle polymers - expensive

Question 15

What is the problem with recycling?

Answer 15

-various types of plastic have to be separated from each other prior to recycling which is expensive, and complete separation is essential
-energy costs with remelt
-costs with transport/collection/cleaning of plastic

Question 16

What is condensation polymerisation?

Answer 16

where monomers with two functional groups join together to make a polymer and a waste product (usually water)

Question 17

What are the two types of condensation polymers?

Answer 17

-polyamides
-polyesters

Question 18

What are the two ways of making polyamides?

Answer 18

-diamine + dicarboxylic acid
-amino acids

Question 19

What are the properties and uses of a polyamide?

Answer 19

-hydrogen bonds formed means that the chains can line up with each other
-the H bonded cross links between polyamide strands give it strength
-kevlar= used to make bullet-proof vests due to tough-sheet like structure

Question 20

Why are polyamides biodegradable?

Answer 20

have polar carbonyl bonds so can undergo hydrolysis when boiled with NaOH

Question 21

How are polyesters made?

Answer 21

condensation polymerisation of 2 different bifunctional monomers - dicarboxylic acid with a diol

Question 22

What is a use of a polyester?

Answer 22

fibres for clothes/carpets, plastic bottles = strong and light

Question 23

What type of bond do polyesters contain?

Answer 23

ester bond C=O - O

Question 24

When polyesters are hydrolysed, we make the

Answer 24

component monomers

Question 25

Discuss the component monomers when hydrolysing polyesters in different conditions

Answer 25

acid hydrolysis - makes the component monomers directly

Question 26

Why are polyesters able to be hydrolysed?

Answer 26

-they have polar carbonyl bonds
-when heated with NaOH solution, the OH- nucleophile will attack the electron deficient carbon atom