Page 715 - Carrahers_Polymer_Chemistry,_Eighth_Edition

678 Carraher’s Polymer Chemistry

21. NR. S, accelerator, antioxidant, carbon black, ZnO, and processing aids.
22. It warms up.
23. They often cost more, are contaminated, and are inferior to synthetic products.
24. A polar solvent, since it is a polyol.
25. Much of it is formed between polysaccharide fibers and thus takes on a somewhat fl at or two-

dimensional structure.
26. (b).
27. At least 60 million tons.
28. Yes, casein is no longer used as a molding resin and, hence the article may have some value as
a collector’s item.
29. There are a number of problems. Essentially, all of them can be overcome. Problems include
public acceptance; fuel delivery; motors that can run on the synthetic fuels that are not so costly
in comparison to gas-fueled engines; reliable and inexpensive fuel production; reliable supply
of the feedstock; and so on.
30. The impediments to the use of any new material are similar to those described in answer 29,
including public acceptance, manufacture costs, reliable feedstock source, and so on.
31. There are not correct or incorrect answers here. Considerations might include searching the
literature and, as Carothers did, look at reactions that occur with phenols and reactions on aro-
matic units for a start and see if any of these might give potentially useful properties.
32. In truth, there is one human race but we choose to differentiate based on a number of charac-
teristics with color being one. Since the major factor in skin color difference is melanin, then it
is a factor when color is used to differentiate humans. Since melanin is not associated with any
other factor than color, it is important to remember that differentiation based solely on color is
only skin deep.
33. Titanium dioxide (titanium (IV) oxide) is the most widely used paint pigment.

CHAPTER 10

1. It is a polyamide.
2. Glycine, because it has no chiral carbon atom.
3. To the positive pole.
4. Collagen has strong intermolecular hydrogen bonds.
5. It should be a linear crystalline polymer with strong intermolecular hydrogen bonds.
6. (b).
7. DNA is usually greater.

− O − − B
8. −(−P−O−S−)−, where B = base, S = deoxyribose sugar.
−
OH

9. (b).
10. Thymine.
11. The presence of bulky pendant groups and hydrogen bonding favors the helical arrangement.
12. TAATGCAGTA.

13. The maximum of 16 dinucleotide combinations is not sufficient to direct the initiation, termi-
nation, and insertion of 20 amino acids in a protein chain; 64 trinucleotide combinations is
more than ample. Further, 2 codons is more easily mixed up, whereas 3 codons is less easily
mixed up.
14. E. coli is relatively harmless, much is known about it, it is easily work with, inexpensive, rapidly
growing, lots of experience working with it.

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