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Polymers Flashcards

1
Q

Define

polymer.

A

a substance that has a molecular structure built up from a large number of similar units (monomers) bonded together

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2
Q

Define

monomer.

A

a molecule that can be bonded to other identical molecules to form a polymer

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3
Q

Define

synthetic.

A

a manufactured substace that imitates a natural product

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4
Q

What are two examples of

natural polymers?

A

rubber and cellulose

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5
Q

What are the positives of

synthetic polymers?

(3)

A
  • easy to process
  • cost-effective
  • available in a wide range of properties
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6
Q

What are some general properties of

polymers?

(5)

A
  • lightweight
  • waterproof
  • tough
  • electrical and/or thermal insulator
  • resistant to atmospheric degradation (don’t rust or rot)
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7
Q

What are the uses of

PET?

(1) and what is its recycling code number?

A

bottles
e.g. for soft drinks, mineral water, fruit juice, cooking oil

1 - PET

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8
Q

What are the uses of

HDPE?

(5) and what is its recycling code number?

A
  • crates
  • bottles
  • pipes
  • buckets
  • bowls

2 - HDPE

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9
Q

What are the uses of

PVC?

(4) and what is its recycling code number?

A
  • pipes
  • guttering
  • roofing sheets
  • window frames

3 - PVC

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10
Q

What are the uses of

LDPE?

(3) and what is its recycling code number?

A
  • squeezy bottles
  • bin liners
  • carrier bags

4 - LDPE

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11
Q

What are the uses of

PolyPropylene?

(4) and what is its recycling code number?

A
  • syringes
  • crates
  • rope
  • containers with built in hinges

5 - PP

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12
Q

What are the uses of

PolyStyrene?

(2) and what is its recycling code number?

A
  • disposable plates
  • food containers

6 - PS

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13
Q

What are the uses of

Expanded PolyStyrene?

(2) and what is its recycling code number?

A
  • sound and heat insulation
  • protective packaging

6 - PS

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14
Q

What are the uses of

nylon?

(3) and what is its recycling code number?

A
  • clothing
  • combs
  • hinges

7 - other

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15
Q

What are the uses of

acrylic?

(3) and what is its recycling code number?

A
  • illuminated signs
  • car rear-light clusters
  • baths

7 - other

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16
Q

What are the uses of

ThermoPlastic Elastomers?

(3) and what is its recycling code number?

A
  • watch straps
  • scuba diving masks
  • remote control buttons

7 - other

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17
Q

What are the uses of

ABS?

(4) and what is its recycling code number?

A
  • safety helmets
  • car parts
  • food mixers
  • toys

7 - other

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18
Q

What are the properties of

PET?

(4) and what type of polymer is this?

A
  • clear
  • tough
  • shatter-resistant
  • good moisture and gas barrier properties

thermopolymer

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19
Q

What are the properties of

HDPE?

(5) and what type of polymer is this?

A
  • range of colours
  • hard
  • stiff
  • good chemical resistance
  • high impact

thermopolymer

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20
Q

What are the properties of

PVC?

(6) and what type of polymer is this?

A
  • stiff
  • hard
  • tough
  • good chemical resistance
  • good weather resistance
  • good sunlight resistance

thermopolymer

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21
Q

What are the properties of

LDPE?

(5) and what type of polymer is this?

A
  • range of colours
  • tough
  • flexible
  • good electrical insulator
  • good chemical resistance

thermopolymer

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22
Q

What are the properties of

PolyPropylene?

(7) and what type of polymer is this?

A
  • hard
  • lightweight
  • good chemical resistance
  • can be sterilised
  • good impact
  • easily welded together
  • good work fatigue resistance

thermopolymer

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23
Q

What are the properties of

PolyPropylene?

(6) and what type of polymer is this?

A
  • stiff
  • hard
  • tough
  • good chemical resistance
  • good weather resistance
  • good sunlight resistance

thermopolymer

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24
Q

What are the properties of

PolyStyrene?

(6) and what type of polymer is this?

A
  • range of colours
  • stiff
  • hard
  • lightweight
  • food safe
  • good water resistance

thermopolymer

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25
Q

What are the properties of

Expanded PolyStyrene?

(4) and what type of polymer is this?

A
  • lightweight
  • absorbs shock
  • good sound insulator
  • good heat insulator

thermopolymer

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26
Q

What are the properties of

nylon?

(6) and what type of polymer is this?

A
  • hard
  • tough
  • resilient to wear
  • self-lubricating
  • good chemical resistance
  • good resistance to high temperatures

thermopolymer

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27
Q

What are the properties of

acrylic?

(9) and what type of polymer is this?

A
  • stiff
  • hard
  • clear
  • durable outdoors
  • easily machined
  • easily polished
  • good range of colours
  • excellent impact resistance
  • scratches easily

thermopolymer

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28
Q

What are the properties of

TPE?

(3) and what type of polymer is this?

A
  • flexible
  • tough
  • will return to original shape after stretching and bending

thermopolymer

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29
Q

What are the properties of

ABS?

(7) and what type of polymer is this?

A
  • tough
  • high impact strength
  • lightweight
  • scratch-resistant
  • good chemical resistance
  • excellent appearance
  • excellent finish

thermopolymer

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30
Q

What are the uses of

urea-formaldehyde?

(2) and what type of polymer is this?

A
  • white electrical fittings
  • wood glue

thermosetting polymer

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31
Q

What are the uses of

melamine-formaldehyde?

(3) and what type of polymer is this?

A
  • tableware
  • decorative laminates for work surfaces
  • electrical insulation

thermosetting polymer

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32
Q

What are the uses of

phenol-formaldehyde?

(2) and what type of polymer is this?

A
  • dark electrical fittings
  • saucepan and kettle handles

thermosetting polymer

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33
Q

What are the uses of

epoxy resin?

(1) and what type of polymer is this?

A

adhesives used to bond different materials
(such as wood, metal, porcelain)

thermosetting polymer

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34
Q

What are the uses of

polyester resin?

(3) and what type of polymer is this?

A
  • boats
  • car shells
  • car bodies

thermosetting polymer

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35
Q

What are the properties of

urea-formaldehyde?

(6)

A
  • stiff
  • hard
  • brittle
  • heat resistant
  • good electrical insulator
  • range of colours
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36
Q

What are the properties of

melamine-formaldehyde?

(7)

A
  • stiff
  • hard
  • strong
  • range of colours
  • scratch resistant
  • stain resistant
  • odourless
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37
Q

What are the properties of

phenol-formaldehyde?

(4)

A
  • stiff
  • hard
  • strong
  • heat resistant
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38
Q

What are the properties of

epoxy resin?

(4)

A
  • good chemical resistance
  • good wear resistance
  • heat resistant (up to 250°C)
  • electrical insulator
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39
Q

What are the properties of

polyester resin?

(4)

A
  • tough when laminated
  • hard
  • strong
  • brittle without reinforcement
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40
Q

What are the uses of

silicone?

(2) and what type of polymer is this?

A
  • flexible baking trays
  • bathroom sealant

elastomer

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41
Q

What are the uses of

neoprene?

(2) and what type of polymer is this?

A
  • wetsuits
  • knee and elbow pads

elastomer

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42
Q

What are the uses of

butadiene rubber?

(2) and what type of polymer is this?

A
  • tyres
  • golf ball cores

elastomer

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43
Q

What are the uses of

fluoroelastomer?

(1) and what type of polymer is this?

A

apple watch sport straps

elastomer

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44
Q

What are the properties of

silicone?

(2)

A
  • excellent heat resistance
  • excellent oil resistance
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45
Q

What are the properties of

silicone?

(2)

A
  • excellent heat resistance
  • excellent oil resistance
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46
Q

What are the properties of

neoprene?

(2)

A
  • weather resistant
  • flame retardant
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47
Q

What are the properties of

butadiene rubber?

(2)

A
  • resistant to abrasion
  • resistant to cracking
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48
Q

What are the properties of

fluoroelastomer?

(2)

A
  • durable
  • resistant to chemicals
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49
Q

What are some

sources of natural polymers?

(3)

A
  • animals’ horns and hooves
  • resin from rubber trees
  • resin from bugs
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50
Q

Define

synthesised.

A

made by combining parts of

e.g. combining different carbon compounds

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51
Q
A

They are made of chemicals which are synthesised from carbon compounds.

These compounds are largely obtained from crude oil.

The crude oil is first fractionally distilled and then some of the products are processed further to produce a chemical.

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52
Q

Define

catalysts.

A

chemicals that cause a reaction to happen

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53
Q

Define

polymerisation.

A

the process of joining small molecules to form polymers

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54
Q

Define

additives.

A

substances added to polymers to improve their mechanical properties

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55
Q

What are some examples of

additives?

(6)

A
  • plasticisers
  • pigments
  • stabilisers
  • fillers
  • catalysts
  • antioxidants
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56
Q

What do

plasticisers do?

A

they improve the flow properties of polymers for moulding

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57
Q

What do

stabilisers do?

A

they help prevent damage from UV light, which can cause several polymers to become brittle

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58
Q

What do

fillers do?

A

they bulk up polymers and reduce costs
they can also improve strength by reducing brittleness and increasing resistance to impact

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59
Q

What do

catalysts do?

and what is an example of this?

A

they speed up the synthesis of polymers

epoxy resin

60
Q

What do

antioxidants do?

A

prevent oxidation

61
Q

What are some

safety concerns surrounding polymers?

(examples of accidents and effects of theses)

A

Producing plastics can be hazardous to workers. Serious accidents have included:
- explosion
- chemical fires
- chemical spills
- clouds of toxic vapour

These kinds of occurences have caused:
- deaths
- injuries
- evacuations
- major property damage

62
Q

What are the

health effects of plasticisers?

A

they are capable of causing cancer

63
Q

What are the

environmental effects of polymers waste products?

A

They end up in landfill. This damages marine ecosystems. For example:
- animals can ingest plastic matter
- animals can become entangled in plastic matter
- floating plastic items can transport microbes, algae and invertebrates into non-native regions

64
Q

What is the

average time taken for a simple PET bottleto degrade?

A

at least 450 years

65
Q

What are some

positives of recycling?

(2)

A
  • reduces the amount of energy and natural resources needed to create new plastic
  • reduces the amount of material dumped in landfill
66
Q

Define

downcycling.

A

recycling into a lower-quality product

67
Q

What are some

negatives of recycling polymers?

(2)

A
  • uses a lot of energy
  • waste polymer needs to be sorted, cleaned and chipped before being melted down into useable granules
68
Q

What is an example of a product that has

reduced the amount of polymer material being used?

A

the new Nestle Eco-Shape bottle uses 30% less plastic and a thinner label than the previous version

69
Q

What is the

waste hierarchy?

A

a set of principles for the efficient use of resources

70
Q

Define

biobased.

A

a product made from a renewable resource

71
Q

Define

biodegradable.

A

the ability of a substance or object to break down naturally in the environment through the action of micro-organisms

72
Q

What is

PLA?

and what are some uses of this?

A

polylactic acid - a biobased polymer derived from cornstarch that breaks down into harmless chemicals when composted

used to make disposable items such as cups, cutlery and food containers

73
Q

What are three examples of how

laws encourage manufacturers and consumers to consider the environment?

(when buying or disposing of products)

A
  • electrical items have a label with their energy rating
  • consumers are encouraged to take their old devices to collection points, from which manufacturers arrange collection
  • new vehicles do not use toxic materials and have all polymer parts labelled to help with recycling
74
Q

Define

stock form.

A

commonly available forms of polymer that can be bought

75
Q

What are some examples of

stock forms of polymer?

(8)

A
  • sheets
  • granules
  • rods
  • extruded sections
  • tubes
  • foamed plastics
  • powdered
  • reels
76
Q

Define

standardised component.

A

an individual part or component, manufactured in thousands or millions, to the same specificatino

77
Q

What are some

standardised components that are commonly manufactured from polymers?

(5 examples with brief detail)

A
  • nuts and bolts - usually made from nylon
  • washers - used to secure fittings
  • wall plugs - used to provide anchors for screws in walls
  • end caps - used to hide the heads of screws or to close pipes/tubing
  • plastic gear wheels - used in various toys and mechanical devices
78
Q

Define

wastage.

A

cutting away material to leave a desired shape

79
Q

What are some different ways of

marking out a polymer?

(so that the design can be cut) (2.5)

and what are the advantages and drawbacks of these?

A
  • a chinagraph pencil - can be wiped of easily but line can sometimes be too thick to follow effectively
  • a non-permanent marker - lines can be smudged easily

a permanent marker can be used on quick early models where progress is more important than a high-quality finish

80
Q

What are some different items used to

cut a polymer?

(4)

A
  • scissors can be used on thin foam sheetd and 0.5mm HIPS
  • craft knives can be used to cut thicker sheets of HIPS
  • coping saws can be used to to cut curves in thin plastic sheet
  • a laser cutter can be used to cut any 2D shape out of acrylic sheet
81
Q

Define

CNC.

A

a computer-controlled machine used in industry

82
Q

What are some ways of

joining polymers together?

(2)

A
  • adhesion
  • heat welding
83
Q

Define

welding.

A

a fusion of metals caused by intense heat

84
Q

Define

line bending.

A

bending a polymer sheet after softening a narrow strip

85
Q

How does

line bending work?

(3) and what is this used for?

A
  1. The sheet material is heated along a line using a strip heater.
  2. Once the material has softened the heater can be removed and the sheet bent to the desired angle using a former or bending jig.
  3. It must then be held in place until the polymer has cooled and become hard again.

it used to create simple bends in polymers sheet

86
Q

How does

drape forming work?

(3) and what is this used for?

A
  1. The polymer sheet is heatd in an oven (to ensure that the whole piece is heated evenly).
  2. Once softened, it is draped over a former and a piece of cloth is pulled tightly across it to hold it in shape until the polymer has cooled.

it used when a large curve or bend is required

87
Q

Define

press moulding.

A

forming a hollow shape from a softened polymer sheet

88
Q

How does

press moulding work?

(4) and what is this used for?

A
  1. The polymer sheet is heated in an oven (to ensure it is heated evenly).
  2. It is then positioned over the plug and and pushed down over it using the yoke.
  3. These are then clamped together until the material has cooled.
  4. Once the piece has cooled you can remove the excess plastic

it used to produce more complex shapes

it is important that the plug has angled sides and rounded edges so that the finished piece can be easiy removed from it

89
Q

Define

vacuum forming.

A

producing thin hollow items over a shaped model

90
Q

How does

vacuum forming work?

(4) and what is this used for?

A
  1. A sheet of suitable polymers (usually HIPS) is fixed across the top of the machine by clamping. This must form an airtight seal.
  2. The plastic sheet is heated evenly until soft.
  3. The heater is moved out of the way, the mould is raised and the air between the mould and the plastic sheet is evacuated by an air pump.
  4. The air pressure on the outside of the sheet then presses the plastic into close contact with the mould

it used in the packaging industry where it is used to form clear plastic into shaped that allow a product to be viewed

the shape of the mould must be carefully designed to allow the plastic sheet to be easily removed and moul reused
the sides must be slightly tapered to produce a draft angle and corners should be radiused

91
Q

Define

92
Q

What are the characteristics of

thermosetting polymers?

A

hard but brittle

this can be made stronger and tougher by using other materials to reinforce it

93
Q

What is

GRP?

A

glass-reinforced plastic - the reinforcement of polyester resin using strands of glass fibre

94
Q

What are the properties of

glass-reinforced plastic?

(5)

A
  • high tensile strength
  • high compressive strength
  • light
  • hard-wearing surface
  • excellent corrosion resistance
95
Q

Define

reinforce.

A

to strengthen or support an object or substance with additional material

96
Q

Define

UV degradation.

A

the weakening of polymers when exposed to the UV light in sunlight

97
Q

Define

stabiliser.

A

an additive added to polymers to help them withstand UV degradation

98
Q

Why are

sheet materials excellent for developing initial ideas?

A
  • quick to work
  • easy to work
  • not too expensive
99
Q

Define

iterative modelling.

A

repeated modelling to develop an idea

100
Q

Define

dichloromethane.

A

a solvent used to join polymer pieces together

101
Q

What are some materials for

making iterative models?

A
  • acrylic sheets
  • styrene sheets
  • foam sheets
  • sticky-bakced vinyl
  • foam board
  • polystyrene foam
102
Q

Define

block models.

A

an informal model that captures the form of an idea

this tends to have no moving parts

103
Q

Why are

polymers so good for iterative modelling?

A

they can be manipulated quickly and easily and can be used for a wide variety of iterative modelling

104
Q

Define

self-finishing.

A

a material that requires no further coatings or finishin processes

105
Q

Define

co-injection moulding.

A

an injection-moulding process that uses two different polymers

106
Q

Define

gate.

A

the entry point for molten plastic to flow into a mould

107
Q

Define

flash.

A

excess material formed between the joint of a mould

108
Q

What are some examples of

finishing processes for polymers?

(4)

A
  • degating
  • deflashing
  • cleaning
  • decorating
109
Q

What is

degating?

A

the process of removing the excess material from injection moulding

110
Q

What is

deflashing?

A

the removal of excess material from moulding

this is often using a knife or other cutting utensil

111
Q

What is

cleaning?

A

spraying or dipping parts in a mild detergent solution then rinsing and drying

this is in order to remove residue, grease and dirt from the machine

112
Q

What are some examples of

decorating a polymer?

A
  • plating
  • vacuum metalising
  • printing
  • painting
113
Q

Define

rapid prototyping.

A

the process of making a 3D shape from a digital file

114
Q

Define

CAM

A

computer-aided manufacture

115
Q

What are some examples of

CAM?

(4)

A
  • stereo lithography
  • laser sintering
  • fused deposition modelling
  • 3D printing
116
Q

What are the steps of

stereo lithography?

(intro + 4 steps)

A

The component is built up in layers on the platform. The liquid is a photopolymer.
1. When the liquid is exposed to UV light from the laser beam, it cures or solidifies.
2. The platform moves downwards, and the sweeper passes over the newly formed layer, breaking the surface tension and ensuring that a flat surface is produced for the next layer.
3. Subsequent layers are laid down, and bind together.
4. The part is then removed from the vat.

117
Q

What are the steps of

laser sintering?

A

The material is a polymer filament.

The polymer is passed through a heating element, melted and extruded.

Each slice of the model is drawn from a continuous length of the molten filament.

118
Q

What are the steps of

3D printing?

(2)

A
  1. A thin layer of material (typically plaster-or-starch-based) is gradually glued together by a print head that can also colour the material using regular printer ink.
  2. The final product is removed from the powder, cleaned and the outer surface strengthened by dipping in Superglue.
119
Q

Define

CAD.

A

computer-aided design

120
Q

Define

CAE.

A

computer-aided engineering

121
Q

Define

FEA.

A

finite element analysis

122
Q

What are some uses of

CAD?

(3)

A
  • create and explore ideas
  • quickly visualise ideas
  • create fully realised products
123
Q

What are some

benefits of CAD?

(4)

A
  • quickly make alterations to components
  • incorporate commonly used components from a built-in online library
  • collaborate on designs with other professionals from aroun the world
  • render product designs in a variety of different colours and materials
124
Q

What is an example of a use for

FEA?

A

testing a model product in a virtual environment for weaknesses

125
Q

What are important considerations when deciding the

scale of production?

A
  • form
  • budget
  • time
  • material
126
Q

Define

one-off production.

and state what this is used for.

A

making only one or a small number of products

this is usually used for epcialist products

127
Q

Define

fabricating.

A

making parts by gluing, turning, carving or welding

128
Q

What is

CNC machining?

A

an example of subtractive manufacturing, which means that the material is cut away from a block

the shape of the parts possible is limited as internal structures are difficult to create

129
Q

Define

batch production.

A

making a set number of identical products

130
Q

Give a brief overview of

vacuum forming.

(4 key points)

A
  • sheets of plastic are warmed and sucked onto a mould
  • there is no need for pressure or high temperatures
  • mould can be made from cheap amterials
  • the shape is quite limited
131
Q

Give a brief overview of

casting.

(3 key points)

A
  • liquid plastic in the form of a resin is poured into a mould and then solidifies
  • moulds are cheap but cannot be reused a number of times
  • parts tend to be quite smalle but can be solid/thick
132
Q

What are the steps of

rotational moulding?

(3) and what is this used to make?

A
  1. A mould containing plastic paste or powder is heated
  2. As the plastic melts and the mould rotates, the plastic coats the surface of the mould cavity with an even layer of plastic.
  3. The mould is then cooled before opening.

it is used to make barrels, tanks, large hollow toys

133
Q

Define

mass/high volume production.

A

producing very large numbers of products

134
Q

Tell me about

compression moulding.

(2 key points)

and give some typical objects made in this way. (4)

A
  • often used for shaping thermosetting plastics
  • the plastic is heated and compressed into shape

typical objects include:
- children’s tableware
- electric plugs
- sockets
- light switches

135
Q

Tell me about

injection moulding.

and give some typical objects made in this way. (7)

A

molten plastic is injected into a mould via an injection screw or ram, cooled and the object is then ejected

typical objects include:
- model kits
- bottle crates
- buckets
- car bumpers
- phone cases
- plastic chairs
- washing-up bowls

136
Q

Tell me about

extrusion blow moulding.

and give some typical objects made in this way. (2)

A

a short tube of melted plastic is extruded and trapped in a mould, then air is blow in so that the plastic take the shape of the mould cavity

typical objects include:
- bottles
- drums

137
Q

Tell me about

thermoforming.

(2 key points)

and give some typical objects made in this way. (6)

A
  • a process used for vacuum forming for mass production
  • an extruded sheet of plastic is heated and then shaped by pressure and/or vacuum

typical objects include:
- chocolate box trays
- packaging trays
- vending cups
- groups of yoghurt pots
- baths
- acrylic sinks

138
Q

Tell me about

extrusion.

and give some typical objects made in this way. (8)

A

molten plastic is pushed continuously through a shaped hole (die) before being cooled

typical objects include:
- drain pipes
- garden hose
- guttering
- rods
- rulers
- sheets
- tubes and pipes
- window frames

139
Q

Tell me about

calendering.

and give some typical objects made in this way. (1)

A

suitable thermoplastic compositions are passed through heated metal rollers with progressively smalle gaps to produce continuous film and precision thin sheet

typical objects include:
- foil

140
Q

Tell me about

blown film extrusion.

and give some typical objects made in this way. (2)

A

it is the process whereby extruded plastic is expanded into a sheath and then wound on to reels

typical objects include:
- packaging films
- ‘plastic’ bags

141
Q

Define

viability.

A

the ability to work successflly

142
Q

Define

stakeholder.

A

a person with an interest in the success of a product

143
Q

Define

tolerance.

A

an allowable amount of variation of a specified quantity

especialy in three dimensions of a part

144
Q

Define

lean manufacturing?

A

a systematic method for the elimination of waste within a manufacturing system

145
Q

What are some ways to

reduce the mount of waste in design?

A
  • designing parts correctly - this will avoid quality issues further down the line that would take more time to correct
  • minimising material - e.g. judging the correct wall thickness
  • reducing the cycle time - investing time in advanced mould design that is able to cool and eject parts faster
  • reusing waste material - excess material from processing can be fed back into the moulding machines

GCSE OCR DT (8 decks)

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