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Chemistry Y13 > Polymers > Flashcards

Polymers Flashcards

1
Q

Polymers

A
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2
Q

what is polymerisation?

A

a polymerisation reaction involves joining together a large number of small molecules (monomers), to form a very large molecule (polymer) ONLY

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3
Q

what are the two different types of poltmers?

A
  • addition polymers and condensation polymers
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4
Q

What is Addition polymerisation?

A

Many monomers join together to form a long molecule (polymers) ONLY

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5
Q

How do alkenes undergo addition polymerisation?

A

Many alkene monomers join together to form a long-chain polymer ONLY

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6
Q

Are there any waste products during addition polymerisation?

A

there are no waste products - only the polymer is formed

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7
Q

what does the addition polymerisation of alkenes occur in? Wjhat is formed during this reaction?

A

in the presence of a catalyst and the alkene monomers link together to form saturated addition polymers

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8
Q

what are addition polymers also known as?

A

chain growth polymers

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9
Q

why are addition polymers also known as chain growth polymers?

A

because they are made by the addition of monomers to the reactive end of the growing chain

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10
Q

Addition polymers are formed via which mechanism?

A

via free radical mechanism

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11
Q

what are the reaction conditions for addition polymerisation?

A

-High pressure and free radical initiator

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12
Q

How can addition polymerisation also proceed through?

A

Cation and anion species. this type of mechanism depends on the structure and the type of catalyst used

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13
Q

how is poly(ethene) formed?

A

ethene molecules link together to form poly ethene (in the presence of a catalyst)

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14
Q

Addition polymers formed from alkenes are?

A

saturated compounds

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15
Q

why are addition polymers chemically unreactive/inert?

A

the carbon-carbon bonds are non-polar and can not be hydrolysed

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16
Q

why is this a useful property for the resultant polymer?

A

since it can not be attacked by acids, alkalis and oxidising agents

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17
Q

draw an equation to show the polymerisation of a SECTION of poly(ethene)?

A
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18
Q

what are polymers usually represented by?

A

a repeating unit

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19
Q

what is the repeating unit of poly(ethene)

A

the repeating unit of poly(ethene) has no brackets

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20
Q

so what is the polymerisation of poly(ethene shown as)

A
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21
Q

what does n stand for?

A

n - represents a large whole number
n - is the number of individual molecules (monomers) that join together to form a polymer

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22
Q

Different addition polymers can be made from..?

A

monomers in which some or all of the hydrogen atoms in ethene have been replaced

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23
Q

draw the structure to show how monomers can be represented by?
What can R be?

A

RHC=CH2
where R = H, CH2, C6H5, CL, CN, OCOCH3

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24
Q

Why can different polymers be used to make a range of commercial products?

A

because each polymer has it’s own physical properties, so different polymers can be used to make a range of commercial products

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25
Q

draw the addition polymerisation of phenylethene, chloroethene and methyl-2-methylpropenoate

A
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26
Q

Problems with disposal

A
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27
Q

why are poly(alkenes) are problem when it comes to disposal?

A

because the carbon carbon bonds in the molecule are non-polar and therefore chemically inert and cannot undergo hydrolysis so when placed in rubbish dumps they will not decay over the years (non-biodegradable)

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28
Q

what is a solution to this?

A

one solution is to use more polymers that are biodegradable so that they will decompose in landfill sites. some plastics have been designed that are completely biodegradable.

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29
Q

But what is the problem with biodegradable plastic?

A

biodegradable polymers are more expensive than traditional synthetic plastics

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30
Q

which type of polymers undergo hydrolysis?

A

poly(esters) and poly(amides) because they are biodegradable by enzyme action

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31
Q

Give another possible solution to disposal of polymers?

A

Incineration

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32
Q

explain what incineration does (advanatges)

A

incineration is the burning of polymers.
- this significantly reduces the volume of waste.
- and can also be sued to recover energy (the heat produced can be used to make steam turbines drive to produce electricity)

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33
Q

what are the disadvantages of incineration?

A
  • produces grennhouse gases (carbon footprint) and other toxic gases (e.g hydrogen cyanide)
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34
Q

Toxic substances from flue gases can be removed but what is the downside?

A

but this requires very high temperature decomposition, which means a high cost process a + equipment

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35
Q

which process is expensive but is a better alternative to landfill and incineration?

A

Recycling

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36
Q

why is recycling good?

A

helps to conserve supplies of non-renewable crude oil

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37
Q

why is the disadvantage of recycling?

A

it is not straightforward and is costly to separate various types of plastics from each other.
complete separation is essential - presence of one rogue bottle will ruin an entire molten plastic batch

38
Q

what are the majority of disposable polymers?

A

Thermoplastics

39
Q

how are thermoplastics reused?

A

need to be melted down and reused

40
Q

what does successful recycling depend on?

A

accumulating enough material of a particular type to re-melt

41
Q

plastics used to package houshold items fall into 7 different types what are they?

A

type 1 - (PETE)
type 2 - (HDPE)
type 3 - (V)
type 4 -(LDPE)
type 5 - (PP)
type 6 - (PS)
type 7 - other - not suitable for recycling

42
Q

what are the other problems associated with recycling?

A
  • the energy costs associated with the plastic re-melt
  • costs associated with the transport, collection and cleaning of disposed plastic
43
Q

Condensation polymers

A
44
Q

condensation polymers form two different types of polymers?

A
  • polyamides
  • polyesters
45
Q

What is condensation polymerisation?

A

where monomers join together to make a polymer and a waste product (only)

46
Q

what is condensation polymerisation formed by?

A

the reaction between molecules that have 2 functional groups

47
Q

what usually happens during condensation polymerisation?

A

monomers with the functional groups at both ends of the molecule join together and a small molecule, usually water (condensation) is eliminated at the end.

48
Q

the waste product is usually water but what else could it be?

A

it can be other small molecules such as CH3OH or HCL

49
Q

Draw a diagram to show the condensation polymerisation between 2 different bifunctional group monomers?

A

Monomer A + Monomer B

50
Q

Draw a diagram to show the condensation polymerisation of 1 monomer with different functional groups at each end react together?

A

Monomer A + Monomer A

51
Q

what are the two types of condensation polymers?

A
  • polyamides
  • polyesters
52
Q

what bond is formed between polyamides?

A

amide bond linkages -O=C-N-H

53
Q

what are the two methods for making polyamides?

A
  1. polyamides can be formed by reacting a diamine with a dicarboxylic acid (or a dioyl chloride)
  2. polyamides can also be formed by the condensation polymerisation of amino acids
54
Q

Show how a polyamide is formed by reacting a diamine (1,6-diaminohexane) with a dicarboxylic acid (Hexanedioic acid)?

A

H2N(CH2)6NH2 + HOOC(CH2)4COOH ——-> -(-H-N-(CH2)6–H-N—-C=O–(CH2)4–C=O–)

55
Q

What product is formed?

A

Nylon 6,6

56
Q

why is it called Nylon 6,6?

A

Nylon 6,6 is so called because it is derived from a 6 carbon diacid and a 6 carbon diamine

57
Q

what is nylon good for?

A

nylon has a large resistance to stress and has many uses such as textiles and carpets

58
Q

Show how a polyamide is formed by reacting a Diamine (benzene-1,4-diamine) with dicarboxylic acid (Benzene 1,4-dicarboxylic acid)

A

H2N-⌬-NH2 + HOOC-⌬-COOH —–> -(–H-N–⌬–H-N—-C=O–⌬–C=O–)-

59
Q

What is the polyamide formed?

A

Kevlar

60
Q

what is the use of Kevlar?

A

Kevlar is used to make bulletproof vests (and skis). Kevlar is very strong and lightweight. it has a tough sheet-like structure due to hydrogen bonding between the polymer chains.

61
Q

Show how a polyamide is formed by reacting a Diamine (benzene-1,3-diamine) with dicarboxylic acid (Benzene 1,3-dicarboxylic acid)

A

Nomex formed

62
Q

What is the use of Nomex?

A

use for making flame-retardant clothing

63
Q

Polyamides can be made by the condensation polymerisation of amino acids

A
64
Q

Show the condensation polymerisation between the amino acid (6-aminohexanoic acid)

A

Nylon 6 formed

65
Q

Show the condensation polymerisation between the amino acid (5-aminopentanoic acid)

A
66
Q

Hydrolysis of polyamides

A
67
Q

Why are polyamides biodegradable?

A

polyamides are broken down by hydrolysis and are therefore biodegradable

68
Q

what is formed during the hydrolysis of polyamides?

A

component monomers are formed

69
Q

why do polyamides undergo hydrolysis?

A

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

70
Q

Draw the hydrolysis of Nylon 6,6

A
71
Q

Draw out the hydrolysis of the dipeptide Val.Ala?

A

forms two separate amino acids Valine and alanine

72
Q

Nylon rope trick

A
73
Q

how can we make the nylon rope?

A
  • carefully pour decanedioyl dichloride (in cyclohexane) down a glass rod into a 100ml beaker containing 1,6-diaminohexane (in water)
  • do not stir the mixture
  • use tweezers to pull out some of the nylon 6,10 from the interface of the two solutions
  • wrap the nylon 6,10 around a glass rod and slowly rotate the glass rod to make a nylon rope
74
Q

Polyesters

A
75
Q

the bonds between the polyesters are called?

A

ester bond linkages

76
Q

How can polyesters be made?

A

Polyesters can be made via a condensation polymerisation reaction involving 2 different bifunctional monomers

77
Q

Recap: how are esters made?

A

by reacting an alcohol with a carboxylic acid

78
Q

How can polyesters be made by reacting..?

A

a dicarboxylic acid (dibasic acid) with a diol

79
Q

Show the formation of the polyester formed when ethane-1,2-diol reacts with hexanedioic acid?

A
80
Q

Show the formation of the polyester when hexane-1,6-diol reacts with butanedioic acid?

A
81
Q

Show the formation of the polyester when ethane-1,2-diol reacts with Benzene-1,4-dicarboxylic acid.

A

Terylene formed

82
Q

what is formed?

A

Terylene

83
Q

what is terylene used for?

A

used for carpet fibres

84
Q

Hydrolysis of polyesters

A
85
Q

How are polyesters hydrolysed?

A

hydrolysed just as normal single esters are hydrolysed

86
Q

what are the polyesters broken down into?

A

they undergo hydrolysis and break down into component monomers

87
Q

polyesters are..?

A

Biodegradable

88
Q

why do polyesters undergo hydrolysis?

A

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

89
Q

What are the uses of polyesters?

A
  • used to make fibres for clothes and carpets
  • polyesters are moulded on a large scale to make plastic bottles for fizzy drinks
90
Q

why are they ideal for this?

A

because they ares strong and lightweight

91
Q

FINISH

A

Chemistry Y13 (13 decks)

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