1. Corrosion examples in shuttle mat'ls

2. Corrosion examples in shuttle mat'ls

3. Corrosion examples in shuttle mat'ls

4. Corrosion examples in shuttle mat'ls

5. Corrosion examples in shuttle mat'ls

6. Corrosion area effect
Area effect:
large cathode & small anode -
corrosion accelerated
electrochemical cell current density high
try to keep potential anodic areas large relative to cathode

7. Polymers - the nightmare begins
I am inclined to think that the development of polymerization is, perhaps, the biggest thing that chemistry has done, where
it has the biggest effect on
everyday life
LORD TODD
President of the Royal
Society of London

8. What are polymers? Why important ?
Long chain molecules
Extraordinary range of
physical properties
Many (not all) are cheap
Low densities

10. Check out chain of beads at right
Check out chain of beads at right. Imagine each bead is an ethylene unit;
How big is n ?
Ethylene Polyethylene C H 2 = [ - ] n
Because only 200 ethylene units in this chain (200 - mer), molecular weight only 5,600
(= 28 x 200).
Question: if chain has a molecular
weight of 420,000, how many ethylene
units does it contain ?
A. 30,000
B. 15,000
C. 150,000

11. How big is n ? Commercially produced polyethylenes
often have MWs of hundreds of thousands. If ethylene unit is 1" instead of a few angstroms
Length of fully stretched out
MW 420,000 chain is almost 1/4 mile! [ - C H 2 ]
= 1 inch

12. Single and Double Bonds
Some Basic Chemistry:
Single and Double Bonds C – H
CH4 C – H
C2H6 C – H
C2H4

13. Some Basic Chemistry: Functional Groups
CH2=CH2
Ethylene
R–OH
R–C–OH = O
R–C–O–R +
Alcohol
Carboxylic Acid
Ester
R–NH2
R–C–OH
R–C–NH–R +
Carboxylic Acid
Amine
Amide = O
Functional groups - small groups of atoms held together in specific arrangement by covalent bonds
Responsible for principal chemical properties of molecule

14. Condensation Reactions
Some Basic Chemistry:
Condensation Reactions O
Ethyl Alcohol
or Ethanol
reversible
reaction
CH3 - C - OH + CH3 - CH2 - OH
CH3 - C - O - CH2 - CH3 + H2O
Acetic Acid
Ethyl Acetate O
Ester linkage

15. Now…to make a Polymer + The molecules are monofunctional:
To make linear chains need bifunctional molecules:
Except, reaction goes step-wise

16. Polyester - step 1 Monomers Dimer O O
HO - C - (CH2)n - C - OH + HO - (CH2)m - OH O O
HO - C - (CH2)n - C - O - (CH2)m - OH + H2O
Dimer

17. Polyester Trimer HO - C - (CH2)n - C - OH O
HO - C - (CH2)n - C - O - (CH2)m - OH +
HO - C - (CH2)n - C - O - (CH2)m - O - C - (CH2)n - C - OH
- H2O
Trimer
Reacting diacid & dialcohol give polyester!
M1 + M M2
M2 + M M3
M2 + M M4
M3 + M M4
M4 + M M5
M3 + M M5
M5 + M M6
Etc.

18. Nylons O H2N - (CH2)6 - NH2 + HO - C - (CH2)4 - C - OH
H2N - (CH2)6 - N - C - (CH2)4 - C - OH + H2O
Adipic Acid
Hexamethylene Diamine
Amide Group H

19. - N - (CH2)6 - N - C - (CH2)4 - C - O n 6 H
Nylon 6,6
“I am making the announcement of a brand new chemical textile fiber ---derivable from coal, air and water -- and characterized by extreme toughness and strength --”
Charles Stine V.P. for research, Du Pont, 1938

20. Nylon
“I am making the announcement of a brand new chemical textile fiber ---derivable from coal, air and water -- and characterized by extreme toughness and strength --”
Charles Stine V.P. for research, Du Pont, 1938

21. Nylon
May “Nylon Day” Four million pairs go on sale throughout US Supply exhausted in 4 days.

22. Nylon Parachute WWII

23. Post WWII stocking sale, San Francisco.