plastics and polymers

Question 1

list 4 polymers

Answer 1

nylon, polyethylene, polyester, Teflon

Question 2

what are mechanical properties

Answer 2

mechanical properties are the characteristics a material displays when subject to an external force

Question 3

list 4 mechanical properties

Answer 3

toughness
flexibility
elasticity
mouldability

Question 4

what is toughness

Answer 4

a polymers ability to absorb energy and deform plastically without cracking by dissipating it.
e.g bike helmets

Question 5

what is elasticity

Answer 5

is a materials resistance to distortion and the ability to return to its original shape
e.g balloons

Question 6

what is flexibility and folding

Answer 6

the ability of a material to be bent or folded without breaking whilst stiffness is a measure of how rigid the material is.

Question 7

mouldability

Answer 7

a polymers ability to be shaped into a form or mould will dictate the type of product it is used for.

Question 8

what two examples of moulding plastics

Answer 8

thermoplastics and thermosets

Question 9

what is the difference between thermoplastics and thermosets

Answer 9

thermoplastics are usually moulded in a hot or molten state under mechanical pressure.

thermosets are usually moulded in could liquid form and cured using a catalyst.

Question 10

what are 7 physical properties

Answer 10

Insulation
Self finishing
UV resistant
Melting points
Transparency and translucency
Resistance to chemicals and liquids
Ability to be combined with other polymers and additives

Question 11

what is the purpose of additives

Answer 11

additives are sometimes used to make polymers easier and more efficient to process

Question 12

what are class the two types of polymers

Answer 12

thermosets and thermoplastics

Question 13

what are synthetic polymers

Answer 13

synthetic polymers are produced from finite recourses such as coal, gas and oil

Question 14

what are natural polymers

Answer 14

natural polymers come from a variety of sources such as rubber and amber, which both come from trees

Question 15

what is the process of getting synthetic polymers

Answer 15

fractional distillation (different polymers are from different fuels)

Question 16

what is polymerisation (4 marks)

Answer 16

-molecules of single compounds known as monomers join together
-these atoms join end to end to form long chains
- the long chains of molecules are called polymers

Question 16

why cant we use large hydrocarbon molecules for polymers

Answer 16

large molecules do not flow very well and aren’t suitable to be made into plastics

Question 16

what happens in cracking with polymers

Answer 16

breaks down large polymers down into smaller more useful ones

Question 17

describe the structure of thermoplastics

Answer 17

-have long chains of molecules, tangled together with no fixed structure of pattern
-generally soft and flexible with some shape memory

Question 18

what is LDPE

Answer 18

low density polyethylene, quite flexible but also tough and is chemical resistant
e.g squeezy bottles or snap lids

Question 19

what is HDPE

Answer 19

high density polyethene, is tough and has higher strength to weight ratio than LDPE and ahs good chemical resistance
e.g rigid plastic toys or buckets

Question 20

what is PP

Answer 20

polypropylene is a tough, flexible polymer with excellent fatigue resistance and resistant to chemicals and solvents
e.g medical equipment or moulded furniture

Question 21

what is HIPS

Answer 21

high impact polystyrene is a rigid lightweight polymer with high impact strength and ability to retain heat
e.g yoghurt pots or plastic cutlery

Question 22

what is ABS

Answer 22

acrylonitrile butadiene styrene is a hard and tough with excellent impact strength and chemical resistance
e.g builders helmets or car bumpers

Question 23

what is PMMA

Answer 23

polymethyl methacrylate is a lightweight tough material relatively poor chemical resistance compared to other polymers
e.g baths or lenses in glasses

Question 24

what is nylon

Answer 24

nylon is the first commercially successful thermoplastic polymer it is durable and resistant to abrasion
e.g tents or seat belts

Question 25

what is rigid PVC

Answer 25

polyvinyl chloride is one of the most widely used polymers and can be both rigid and flexible it has good chemical and weather resistance
e.g plumbing or external doors

Question 26

what is flexible PVC

Answer 26

plasticisers are added to PVC to increase flexibility it is water and chemical resistant
e.g inflatable products or alternative leather

Question 27

describe thermosets

Answer 27

thermosets are more brittle than thermoplastics and are best suited to stiffer mouldings , cant be reheated or reshaped

Question 28

what are stock forms

Answer 28

the standard shapes and sizes in which a material is available

Question 29

list 6 stock forms

Answer 29

• sheet
• film
• granules
• rod and other extruded forms
• foam
• powder

Question 30

what are elastomers

Answer 30

elastomers are polymers that are highly elastics and capable of recovering their original shape after being stretched most elastomers are thermosets

Question 31

name some examples of elastomers

Answer 31

thermoplastic elastomers
stretching elastomer
grip based elastomers
texture based elastomers

Question 32

what is vulcanisation

Answer 32

vulcanisation is a process used to cure rubber making it harder, more durable and heat resistant