Polymers

Question 1

How are plastics made

Answer 1

synthetic plastics have replaced wood/metal in manufacturing, commercial production of plastics really started after WWII. The raw materials are coal/oil. Contain a number of different chemical which can be sperated into parts - fractional distillation

Question 2

Plastics manufacture - How is it formed into products

Answer 2

plastic products are made by heating the plastic and using a mould, a former or a cast

Question 3

Why is plastic used compared to other materials

Answer 3

it is cheaper than similar products made from wood/metal because:
raw materials and extraction is cheaper, less energy is needed to make the product, products = easily mass produced, transport costs are less

Question 4

What are the problems in using plastics

Answer 4

they have a long shelf life which means they are difficult to dispose of aa they don’t rot or corrode, if burnt they product black choking gasses, production of plastics = polluting, PVC contains nasty pollutants and difficult to recycle, when molten they are sticky and cause severe burns, thermoplastics can be recycled by reforming but limited with frequent heating, sustainability = designers have to take into consideration 6r’s

Question 5

Thermoplastics definition

Answer 5

weak bonds break allowing the plastic to become semi-fluid and reshaped, the physical structure is changed not a chemical change, process can be repeated if not overheated so they are recyclable

Question 6

Name the different types of thermoplastic

Answer 6

polyethylene terephthalate (PET), high density polythene (HDPE), Low density polythene (LDPE), polyvinyl chloride (PVC), polypropylene (PP), polystyrene (PS), Acrylic (PMMA), polycarbonate, ABS

Question 7

AD and DIS of polyethylene terephthalate (PET) and common uses

Answer 7

AD - easily recyclable
DIS - one time use
CU - clothing, container of food an liquid

Question 8

AD and DIS of high density polythene (HDPE) and common uses

Answer 8

AD - tough, can be blow moulded, can be extrusion injection moulded
DIS - brittle
CU - bottles (bleach), toys, buckets, piping - medium use items

Question 9

Low density polythene (LDPE) common uses

Answer 9

CU - thin film, carrier bags, wiring insulation, squeezy bottles

Question 10

AD and DIS of polyvinyl chloride (PVC) and common uses

Answer 10

AD - strong, stiff, chemical and weather resistance
DIS - toxic fumes released during production
CU - window frames, gutters, disposable pens

Question 11

AD and DIS of polypropylene (PP) and common uses

Answer 11

AD - versatile, flexible without breaking, withstand variable temp
DIS - low UV resistance
CU - garden furniture, tubs, binders - long use items

Question 12

Different types of polystyrene (PS) and common uses

Answer 12

expanded polystyrene = packaging - light and impact absorbent
high impact polystyrene = vacuum forming - household items as good impact strength, rigid

Question 13

AD and DIS of Acrylic (PMMA) and common uses

Answer 13

AD - strong, good insulator, can be: vacuum formed, line bent, blow moulded
DIS - scratches easily
CU - car headlights, street signs

Question 14

AD and DIS of polycarbonate (PC) and common uses

Answer 14

AD - high strength, transparent, good resistors of heat/chemicals
DIS - can be scratched
CU - CD packaging, bus shelters, car lights

Question 15

AD and DIS of ABS and common uses

Answer 15

AD - strong, tough, scratch resistant, impact resistant
DIS - low melting point
CU - lego, kettles, vacuum cleaners

Question 16

Thermoset definition

Answer 16

they undergo a chemical change so once heated/chemically changed this is their final form as they form strong bonds, it is difficult to injection mould as heat changes them immediately which means they can’t be recycled

Question 17

Name the different types of thermoset plastics

Answer 17

urea formaldehyde, melamine formaldehyde, polyester resin, epoxy resin

Question 18

AD and DIS of urea formaldehyde and common uses

Answer 18

AD - hard, good insulator
DIS - brittle
CU - electrical plugs, sockets, switches

Question 19

AD of melamine formaldehyde and common uses

Answer 19

AD - scratch/water/stain resistant
CU - laminate in kitchen work surfaces, hard small heat resistant products - cup/dishes

Question 20

AD and DIS of polyester resin and common uses

Answer 20

AD - combined with fibreglass to produced glass reinforced plastic
DIS - toxic fumes
CU - boat hulls, car parts

Question 21

Epoxy resin common uses

Answer 21

mixed with a hardener and left to set
CU - adhesives, flooring

Question 22

How to finish acrylic when hand cut and why is this nessersary

Answer 22

hand cutting leaves marks so you would cross file first, then draw file and then sand it with wet and dry paper (P800+)

Question 23

Elastomers definition

Answer 23

thermosetting, it has a springy bond some like rubber can be vulcanised to make them rigid, they can be stretched repeatly and still return to their original shape, non-toxic, often used on top of other products

Question 24

Name the different types of elastomers

Answer 24

natural rubber, butadiene rubber (BR), neoprene, silicone

Question 25

AD and DIS of natural rubber and common uses

Answer 25

AD - good hardness in comparison to other elastomers, good cold resistance, widely used and available CU - tyres

Question 26

Butadiene rubber common uses

Answer 26

CU - mostly tyre production, additives to polystyrene, synthetic rubber

Question 27

Neoprene common uses

Answer 27

CU - laptops sleeves, remote controls, mouse pads, lifestyle and home accessories

Question 28

AD of silicone and common uses

Answer 28

AD - biocompatible, hypoallergic, does not react with most chemical/biological processes CU - suitable for baby care products/food, medical use

Question 29

Biodegradable polymers definition

Answer 29

most polymers care made from non-renewable finite sources, polymers can be produced from cellulose (wood, sugar, starch), biopolymers can be split into 2 categories - natural/synthetic,

Question 30

Polymer degradation definition and give the definitions of the types of degradation

Answer 30

polymers degrade due to chemical/heat/light 2 main types: - polymer is made from finite resources but has additive designed to make it break down faster (5 years), - polymer breaks down due to micro-organisms

Question 31

Name the different types of biodegradable polymers with additives

Answer 31

oxy-degradable polymers, photo gradable polymer, hydro degradable polymer

Question 32

Definition of oxy-degradable polymers

Answer 32

the polymers break down into a fine powder with oxygen through microorganisms

Question 33

Definition of photo gradable polymers

Answer 33

breaks down with uv, used in agriculture

Question 34

Definition of hydro polymers

Answer 34

breaks down with exposure to water, used in liquid detergent sachets

Question 35

Implications of biopolymers

Answer 35

release methane gas - global warming - toxic, need land to grow - can't be recycled

Question 36

Name the different types of biodegradable polymers without additives

Answer 36

corn-starch polymers, potatoPAK, PHA and PHB, PLA, lactide glycoclide

Question 37

Definition, AD and common uses of corn-starch polymers

Answer 37

made from veg starch AD - biodegradable if composted and can be used for animal feed, sustainable. readily decompose CU - packaging

Question 38

Definition, AD and common uses of PotatoPAK polymers

Answer 38

potato starch, cellulose, water = heated and pressed into shape CU - bowls, cutlery, food trays

Question 39

Definition, AD, DIS and common uses of PHA and PHB

Answer 39

polymer produced by natural microorganisms AD - brittle, stable, strong, moulded easily DIS - little chemical resistance CU - bottles, food items, household items

Question 40

Definition, AD and common uses of PLA

Answer 40

made from renewable biomass AD - non-toxic, easily moulded, can be made in a range of colours and textures CU - bottles, food packaging, 3D printer filament

Question 41

Definition common uses of lactide, glycoclide

Answer 41

additives CU - food wraps, bags, bin bags

Question 42

Polymer finishing definition

Answer 42

polymers are self finishing, any finishes like textures and pigments are 'additives' that re included during the processing or textures on the mould

Question 43

Name the different types of polymer finishes

Answer 43

acrylic spray paint, over moulding

Question 44

Acrylic spray paint definition

Answer 44

requires preparation and can be added to change colour or colour match existing parts, most cost effective to spray colour than change pigment for each part

Question 45

Over moulding definition

Answer 45

usually a rubbery plastic added to the main product to improve grip, injection moulded as 2 separate pieces or twin injection

Question 46

Poly enhancements definition

Answer 46

(not finishes) - characteristics can be enhanced to improve working properties/aesthetics

Question 47

What machining properties can be changed in polymers

Answer 47

Machining properties: lubricants can be added to make the plastics flow better into moulds during manufacture Thermal antioxidants can be added to stop discolouring during manufacture

Question 48

What aesthetics properties can be changed in polymers

Answer 48

pigments can be added prior to manufacture to change colour, these are small particles added into the mix before forming the product

Question 49

What functional properties can be changed in polymers

Answer 49

antistatic additives are added to avoid static build up on electrical insulating parts, flame retardants are added to reduce likelihood of plastics catching fire, plasticisers are added to make the plastic less brittle, fillers can be added to bulk out the material requiring less plastic and/or minerals can be added to help with thermal conductivity

Question 50

What life extension properties can be changed in polymers

Answer 50

antioxidants can be added to prevent degradation form oxygen, UV stabilisers can be added to prevent degradation from sunlight, this usually stops materials becoming brittle or loosing colour

Question 51

What degradation properties can be changed in polymers

Answer 51

biodegradable plasticisers can be added to speed up degradation