Materials

Question 1

What are plastics developped from?

Answer 1

petroleum and fossil fuels

Question 2

what are the building blocks of plastics

Answer 2

monomers which form polymers

Question 3

name the two types of plastics

Answer 3

• thermoplastics
• thermosetting

Question 4

what is a thermoplastic?

Answer 4

a plastic that becomes soft when heated to be molded and that hardens (3/4 plastics in the category)

Question 5

what is thermosetting

Answer 5

a plastic the remains permanently shaped, even when heated. Made by adding monomers to a mold, once hardened cannot be chnaged. (melamine and polyesters) can’t be recycled

Question 6

list the 2 signs of degradation for ceramics

Answer 6

• cracking
• change in colour

Question 7

list some types of degredation and how to combat them

Answer 7

• Penetration of liquid—-add water proof coating
• Oxidation —- add antioxidants (carbon black)
• Ultraviolet rays —- add dark pigments to absorb UV rays

Question 8

how do ceramics form

Answer 8

when certain inorganic compounds (metal & non-metal) is extremely heaed, the water in it evaporates and the bonds between the compounds are created to form ceramics

Question 9

list some examples of ceramics

Answer 9

bricks, clay, pots, glass

Question 10

list some forms of degradation for ceramics and how to fix them

Answer 10

• exporsure to H2SO4 or Ca(OH)2——-avoid exposure
• Thermal shock—– avoid exposure to extreme temperature fluctuations

Question 11

what are composites composed of

Answer 11

matrix and reinforcement

Question 12

describe a plastic matrix and its properties

Answer 12

thermoseting plastics are most often used as matrices and are often referred to as resins.
* Durable
* Lightness
* Resilience
* Low cost

Question 13

describe a metallic matrix and its properties

Answer 13

made of metals or alloys
* ductile
* conductive
* stiff

Question 14

describe a ceramic matrix and its properties

Answer 14

made of ceramics, often glass
* durable
* heat resistant

Question 15

describe fiberglass reinforcement and its properties

Answer 15

made of fiberglass (ceramic) in the form of fibers
* stiffness
* corrosion resistance

Question 16

describe aramind fibers reinforcement and its properties

Answer 16

known as kevlar and one of the few plastics used as reinforcement
* low density
* resilience

Question 17

describe carbon fibers reinforcement and its properties

Answer 17

obtained by carbonizing polymers
* stiffness
* low density
* electrical conductivity

Question 18

list some forms of degradation for composites and how to fix them

Answer 18

• deformation or breaking of the matrix or reinforcements—–avoid misuse
• a lost of adherence between the matrix and reinforcement —- adhere well

Question 19

what are alloys

Answer 19

a mix of metal & metal or metal & nonmetal

Question 20

how can metals and alloys degrade

Answer 20

they can oxidize or chemically alter if exposed to the elements (acid rain, rain, salt, oxygen)

Question 21

how do you protect metals and alloys?

Answer 21

coating with other metals OR
coating with paint, enamel, grease, resin and antioxidants can be applied if the alloy contains metal to avoid rust.

Question 22

describe modified wood

Answer 22

it’s altered wood as it is mixed with other substances like glue. this is less costly and often harder than wood

Question 23

describe the degradation of wood and how to fix it

Answer 23

fungi, microorganisms and insects can infest and feed off wood——coat it with varnish, high heat treatment which removes water