plastics, elastomers and ceramics

Question 1

what are polymers?

Answer 1

lightweight, corrosions resistant, electrical insulators with relatively low tensile strengths and melting points

Question 2

why are they so popular?

Answer 2

ease with which they can be used to manufacture products and relatively low density

Question 3

polymers are based on?

Answer 3

long chains of molecules

Question 4

long chains are constructed from?

Answer 4

smaller molecules called monomers

Question 5

the stress strain behaviour of polymers is?

Answer 5

generally non linear and time dependant

Question 6

polymers exhibit both elastic and non elastic behaviour

Answer 6

elastomers are rubber

Question 7

do ceramics creep?

Answer 7

no

Question 8

everyday examples of ceramics?

Answer 8

brick and glass

Question 9

3 categories of composites?

Answer 9

particulate, fibre and laminar

Question 10

name of test used to test a structures resistance to impact loading?

Answer 10

charpy test

Question 11

what is the energy absorbed by the structure called?

Answer 11

impact energy

Question 12

why are alloys used in orthopaedic implants resistant to corrosion?

Answer 12

derived from an inert film covering the surface of the metal, usually an oxide, called the passivation layer

Question 13

stainless steels contain 12-18%?

Answer 13

chromium

Question 14

what gives stainless steel its corrosion resistant property?

Answer 14

chromium

Question 15

name of the alloy used in orthopaedics?

Answer 15

316L (l for extra low carbon)

Question 16

titanium based alloys have a higher strength to weight ration than aluminium

Answer 16

a fatigue fracture has relatively smooth region marked by concentric markings that may allow the origin of the fracture to be found. The rest of the fracture is granular or fibrous in appearance.

Question 17

fatgue fracture = stress fracture = march fracture

Answer 17

y

Question 18

plastics can be divided into ?

Answer 18

thermoplastics and thermosets

Question 19

what do thermoplastics display?

Answer 19

plastic behaviour at high temperatures

Question 20

which ones can be reformed?

Answer 20

thermoplastics

Question 21

can not be reformed as during their formation at high temperatures, a by product is released from the material. harden at certain temperatures. this respects their recyclability

Answer 21

y

Question 22

everyday examples of ceramics?

Answer 22

brick and glass