Lecture 1

Question 1

What are the 3 main classes of materials?

Answer 1

polymer, ceramic and metal

Question 2

mechanical properties of Metal ceramic and polymers?

Answer 2

M: hard, tough, strong
C: Hard Brittle, strong
P: soft, ductile weak

Question 3

What are thermal processing properties of metal ceramic and polymers?

Answer 3

M + C req heat. (except amalgams and cements)

P: req low processing temps

Question 4

What are bonds like in metals ceramics and polymers?

Answer 4

M: sea of e-
C: ionic and covalent
P: covalent ( strongest )

Question 5

How do you process metals?

Answer 5

Heat until it forms crystals and strengthen using alloy

Question 6

how are cements processed

Answer 6

form crystalline structure of SiO4 building blocks

Question 7

How are polymers processed

Answer 7

bind into long chains w/ high mol. weight using free radical chem

Question 8

Steps of Polymerization

Answer 8

1. Activation: break initiator into free radicals
2. Initiation: free radicals attack monomers
3. propagation: monomers linked into a chain
4. termination: no more unreacted monomers

Question 9

what happens to volume during propagation phase?

Answer 9

decreases

Question 10

polymerization is activated by:

Answer 10

light, heat or chemical mixing

Question 11

difference btwn linear and crosslinked polymer

Answer 11

linear = monomethacrylate (has 1 polymerizable unit)
crosslinked = dimethacrylate (has 2 polymerizable units so it branches and is used for adhesives and wont dissolve

Question 12

what are composites?

Answer 12

mixtures of metals ceramics and/or polymers

Question 13

what’s the rule of mixtures?

Answer 13

if you know the phases present in a material and interfacial interactions, you can predict the overall properties

Question 14

how do fillers affect final properties of composites?

Answer 14

fillers bind w/ resin.

Question 15

What happens if you increase the filler volume or size?

Answer 15

^ volume: ^ viscosity, ^ modulus, ^ strength, and decrease shrinkage
^ size: ^ surface roughness

Question 16

factors that contribute of materials’ mechanical properties ( metal ceramic and polymer)

Answer 16

polymer: entaglement gives strength
Ceramics: crystal SiO4 structure
Metals: polycrystalline structure/alloys

Question 17

thermal expansion coefficient

Answer 17

relative range of change during temp change; heat expands, cold contracts

Question 18

chemical implications of heat flow:

Answer 18

pulps can tolerate limited changes of temp for brief periods b/c they can’t dissipate heat. metals may need a base b/c they’re so conductive

Question 19

how do we define color?

Answer 19

3D coordinate system based on hue, chroma, and value

Question 20

what are hue chroma and value?

Answer 20

hue: wavelength (roygbiv)
chroma: purity/density
value: brightness/intensity

Question 21

what’s metamerism

Answer 21

seeing two things look the same color in 1 light and different colors in another light