Polymer characteristics

Question 1

what is toughness?

Answer 1

the ability to absorb energy and deform plastically without cracking [bike helmet]

Question 2

what is elasticity?

Answer 2

resistance to distortion and ability to return to its original shape [balloon]

Question 3

what is flexibility?

Answer 3

the ability to be bent or folded without breaking [pvc film]

Question 4

what is stiffness?

Answer 4

measure of how rigid a material is [thermosets]

Question 5

what is mouldability?

Answer 5

ability to be shaped into a form or mould [thermoplastics]

Question 6

what determines weather a polymer can be cut or scored?

Answer 6

its hardness

Question 7

what is a thermal insulator polymer + 1 use

Answer 7

• insulators reduce heat transfer
• formed with air inside to make foams
• used on utensil handles [saucepans]

Question 8

what are electrical insulators + 1 use

Answer 8

• doesn’t allow electricity to flow freely through

- used for electrical casings

Question 9

what is the melting point of a polymer and what does this dictate?

Answer 9

• temperature it turns from a solid to liquid

- melting points dictate polymers use

Question 10

what happens to thermoplastics and thermosets at high temperatures?

Answer 10

• thermoplastics become soft, pliable and ‘plastic’

- thermosets don’t melt but decompose and char

Question 11

what is a thermoplastic?

Answer 11

a polymer that melts at high temperatures but solidifies when cooled

Question 12

what is a thermoset?

Answer 12

polymer that is irreversibly hardened via curing

Question 13

what does UV do to polymers and which one is UV resistant?

Answer 13

• UV bleaches the colour of polymers
• makes them brittle
• ABS retains its colour so is most UV resistant

Question 14

what polymer is most resistant to chemicals and where is it typically used?

Answer 14

HDPE [high density polyethene]

used for bleach bottles and to line landfill sites

Question 15

what are the differences between using PET and HDPE for drink bottles?

Answer 15

• both liquid resistant
• HDPE is reusable and recyclable
• PET is recyclable and can leach chemicals into the water after reuse

Question 16

why are polymer films and moulded polymer used for food packaging?

Answer 16

• hygienically protect the food by making a barrier to oxygen, tampering and airborne threats
• prolong the shelf life to keep flavor and quality of the food

Question 17

how are food bags, pots and films adapted for packaging?

Answer 17

• can be heat sealed
  -allow cooking whilst in the packaging
  [ready meals]

Question 18

how do additives increase the biodegradability of thermoplastics?

Answer 18

• thermoplastics degrade slowly and leave plastic particles polluting the soil
• bio-batch additives allow the thermoplastic to be broken down quicker by natural bacteria

Question 19

what is recycling?

Answer 19

process of recovering waste and reprocessing it into useful products

Question 20

what does recycling do to polymers?

Answer 20

• prevents it ending up in landfill

- reduces the production of new material from finite resources

Question 21

what are finite resources?

Answer 21

non-renewable [coal]

Question 22

why are polymers self finishing?

Answer 22

• they require no additional surface finishing
• they take the surface of the mould they were in
• pigments can be added to reduce the need for secondary surface colouring

Question 23

what 2 things do plasticisers do?

Answer 23

enhance flow characteristics so polymers can be moulded at higher temperatures
also make polymers streatchy

Question 24

what do thermal antioxidants do?

Answer 24

help prevent oxidation due to heat exposure

Question 25

what do lubricants do?

Answer 25

improve polymer flow by decreasing viscosity

Question 26

what do antioxidants do?

Answer 26

reduce degradation from air and water to prevent cracking and discolouration

Question 27

what do UV light stabilizers do?

Answer 27

improve the resistance to UV radiation

Question 28

what do fire retardants do?

Answer 28

increase fire resistance

Question 29

what do antistatic additives do?

Answer 29

reduce the build up of static charge

Question 30

what 6 stock forms are polymers found in?

Answer 30

sheet, film, granules, extruded [rods], foam and powder

Question 31

what are the 3 different types of polymer sheet with 1 characteristic?

Answer 31

- solid cast [extruded]- acrylic for kitchens - fluted sheet- has channels in it for folders - laminated sheet- foam board has 2 card around 1 foam layer

Question 32

how can polymer sheets be used?

Answer 32

in their flat form and can be cut or moulded

Question 33

what are the 4 types of film?

Answer 33

packaging, membranes, carrier bags and photographic

Question 34

why are granules used for moulding?

Answer 34

- easier to process - easier to measure - melt quicker

Question 35

where are plastic granules used?

Answer 35

- playground surfaces - filling stuffed toys - cosmetic products

Question 36

how do you make polymer granules into a rod? +1 use

Answer 36

- Nylon and PP granules are melted - extrusion forms them into a continuous profile - bearings and gears

Question 37

what polymers can undergo extrusion?

Answer 37

PVC, PP and HDPE

Question 38

what products are made by extruding polymers?

Answer 38

- window frames - tubing - seals and mouldings - adhesive tapes - wire insulation

Question 39

what ingredients make foam?

Answer 39

polymer with additive/catalyst, heat, air or gas

Question 40

what happens when foam is mixed?

Answer 40

- expands - gas bubbles form and pop - makes a spongy porous form

Question 41

what can foam be used for?

Answer 41

- exercise mats - packaging - insulation - soft furnishings - model making

Question 42

what are powder polymers used for?

Answer 42

- protect metals from corrosion | - for 3D printing when laser cured

Question 43

how are metals painted with powder?

Answer 43

- metals are electrically charged or heated - dipped or spayed in powder - then cured

Question 44

what are the properties of foam board? +1 use

Answer 44

- lightweight - easy to cut and score - solvents can melt it - presentation boards and model making

Question 45

what are the properties of Fluted Polypropylene +1 use

Answer 45

- creases - bends - integrated channels - folding boxes, folders and signage

Question 46

what are the properties of translucent PP + 1 use

Answer 46

- tough - tear resistant - water resistant - printed or laser cut - flexible - coloured or clear - document folders, lightweight boxes

Question 47

what is Styrofoam?

Answer 47

dense, extruded blue foam

Question 48

what are the properties and uses of styrofoam?

Answer 48

- available in sheets or blocks - comes in a range of thicknesses - cut and shaped - used for model making or moulds/formers

Question 49

Properties of LDPE and where is it used?

Answer 49

- tough, flexible sheet - good chemical resistance - thin films or sheets - food wrap, bags [bin/freezer], bubble wrap

Question 50

what are the properties of Plastazote [engineered foam] and its uses?

Answer 50

- tough , flexible and lightweight - impact resistant - insulator - yoga mats or pipe covers - protective packaging

Question 51

what is cellulose acetate and its properties?

Answer 51

naturally derived biodegradable film - tough - transparent

Question 52

what are 2 uses for cellulose acetate?

Answer 52

- photographic film | - biodegradable packaging

Question 53

what is Polylactide acid [PLA] and what are its properties?

Answer 53

- biodegradable polymer - recyclable - compostable - low impact resistance

Question 54

what is PLA made from and why is this a problem?

Answer 54

- corn starch and sugar beet | - requires a large amount to make the polymer

Question 55

what is PLA used for?

Answer 55

replaces PET for biodegradable packaging

Question 56

what is transparency?

Answer 56

how permeable a material is to light radiation

Question 57

what is translucent?

Answer 57

when some light can pass through but is diffused so the object isn't clear to see

Question 58

what is opaque?

Answer 58

when the material is impermeable to light