Page 183 - Carrahers_Polymer_Chemistry,_Eighth_Edition
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146                                                    Carraher’s Polymer Chemistry

                 EXERCISES

                   1.   Which of the following will give a polymer when condensed with adipic acid: (a) ethanol,
                     (b) ethylene glycol, (c) glycerol, (d) aniline, or (e) ethylenediamine?
                   2.   Could Carothers have produced strong polyester fibers by ester interchange or Schotten–

                     Baumann reactions using aliphatic reactants?

                   3.   Which would be useful as a fiber: (a) PET or (b) poly(hexylene terephthalate)?
                   4.   If the fractional conversion in an ester interchange reaction is 0.99999, what would be the aver-
                     age DP of the polyester produced?
                   5.   Use the logarithmic form of the Arrhenius equation to show that the value of the rate constant
                     k increases as the temperature increases.

                   6.   What is the first product produced when a molecule of sebacyl chloride reacts with a molecule
                     of ethylene glycol?
                   7.   What is the next product formed in question 6?
                   8.   How would you improve the strength of the fi lament produced in the nylon rope trick without
                     changing the reactants?
                   9.   Name the product produced by the condensation of adipic acid and 1,4-
                     tetramethylenediamine?
                 10.   In which reaction would you expect the more “wasted loop”: the reaction of oxalyl chloride with
                     (a) ethylenediamine or with (b) 1,6-hexanediamine?
                 11.   Which system would be more apt to produce “wasted loops: (a) a dilute solution or (b) a con-
                     centrated solution?
                                                         –3
                 12.   If the values of A  and k are 10 mol/L and 10  L mol/s, respectively, how long would it take to
                                   o
                     obtain an average DP of 37?
                 13.   Which will give the lower index of polydispersity: (a) p = .000 or (b) p = .90?
                 14.   If you used a 2% molar excess of BPA with TDI, what would be the maximum average DP
                     obtainable assuming p = 1?
                 15.   Why would you predict that the product obtained in question 14 be a useful fi ber assuming an
                     average DP of 100?
                 16.   Name the product formed from the reaction of a phenol with formaldehyde.
                 17.   Give the Carother’s equation. What is its signifi cance?
                 18.   What is the product of polymerized formaldehyde? Is it stable?
                 19.   What is the product of a diol and diisocyanate? What are general uses of this product?
                 20.   Which would be the better or stronger fiber: one made from an ester of (a) terephthalic acid or

                     of (b) phthalic acid?
                 21.   What would be the deficiency of a nylon film that was stretched in one direction only?



                 22.   Which would be more flexible: (a) PBT or (b) poly(hexylene terephthalate)?
                 23.   Which would be more apt to deteriorate in the presence of moisture: (a) Lexan molding powder
                     or (b) Lexan sheet?
                 24.   What reactants are typically employed to make a PC?
                 25.   How would you prepare a nylon with greater moisture resistance than nylon-66?
                 26.   How would you prepare a nylon that would be less “clammy” when used as clothing?
                 27.   Which would be higher melting: (a) a polyamine or (b) a polyester with similar members of
                     methylene groups in the repeat unit?

                 28.   Why is a methoxymethylated nylon more flexible than nylon?
                 29.   Why Bakelite not used in forming molded objects?
                 30.   Isn’t it wasteful to decompose a diisocyanate by hydrolysis to produce foams?
                 31.   How would you prepare a hydroxyl-terminated polyester?
                 32.   For the acid-catalyzed condensation of ethylene glycol with terephthalic acid, what is the rela-
                     tionship between DP and extent of reaction?









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