Page 711 - Carrahers_Polymer_Chemistry,_Eighth_Edition

674 Carraher’s Polymer Chemistry

8. H C
3
R
R R
R
R
R
O O
—
Cl CH 3
(a) (b) (c)

9. Since the rate of termination has decreased, more monomer may be added gradually to produce
high molecular weight polymers.
10. Initiation, which is governed by the rate of production of free radicals.
11. (a).
12. Monomeric styrene.
13. Ln 2 = 0.693.
14. Measure the volume of N produced (given off).
2
15. About 30–50 kcal/mol.
16. One may polymerize at low temperatures and also regulate the rate of production of free
radicals.
17. PVC degrades when heated in a furnace giving hydrogen chloride that can damage the metal in
the furnace. With respect to the ozone layer, PVC is also a minor source of chlorine. Counter,
PVC piping is very important and its use allows the “non-use” of many metals whose production

has potentially a greater negative influence on the environment.
18. (a), (b), and (c) = 1 × 10 mol/L, assuming monomer is still present.
−11
19. 5 ± 3 kcal/mol.
20. R is proportional to [I] .
1/2
p
21. The average DP decreases.
22. Steady-state number of polymerizing or growing chains; rate of termination is equal to rate of
initiation; steady state for initiator radical.
23. Vinyl acetate is obtained by hydrolysis of poly(vinyl acetate).
24. Advantage—simple equipment; disadvantage—bad heat control, broad molecular weight, may
require further purifi cation.
25. Neither; it remains unchanged.
26. Ethylene has no electron-donating groups, and is less polar than isobutylene.
27. Disproportionation.
28. The termination mechanism at higher temperatures is disproportionation.
29. 0–6 kcal/mol.
30. T = 61ºC. Therefore, poly(α-methylstyrene) would decompose when heated above 61ºC.
c
31. Teflon is the trade name and was widely advertized.

32. (b). The bond strength for C–Cl is less.
33. The H C(CH ) S produced by chain transfer is an active free radical that initiates new chains.
.
2 11
3
34. No, the heat from the exothermic reaction might cause an explosion.
35. They are the same.
36. No, but one should avoid contact with the skin and ascertain that there is a minimal amount of
monomer, which is done industrially before it is sold, residue in the polymer.
37. Good slippery behavior, good thermal and corrosive resistance, good inertness.
38. The droplets are relatively few in number, and the chances of an oligoradical entering them is
small.
39. The primary free radicals are water soluble.
40. The initial polymerization rate would be retarded.
41. Styrofoam packing and cups, bottles, disposable egg cartons.

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