1
00:00:00,030 --> 00:00:02,400
The following content is
provided under a Creative

2
00:00:02,400 --> 00:00:03,840
Commons License.

3
00:00:03,840 --> 00:00:06,840
Your support will help MIT Open
Courseware continue to

4
00:00:06,840 --> 00:00:10,520
offer high-quality educational
resources for free.

5
00:00:10,520 --> 00:00:13,390
To make a donation or view
additional materials from

6
00:00:13,390 --> 00:00:17,430
hundreds of MIT courses, visit
MIT Open Courseware at

7
00:00:17,430 --> 00:00:18,680
ocw.mit.edu.

8
00:00:22,580 --> 00:00:23,070
Hi.

9
00:00:23,070 --> 00:00:23,700
I'm Brian.

10
00:00:23,700 --> 00:00:26,730
We're going to be going over
problem number 13 of the fall

11
00:00:26,730 --> 00:00:29,030
2009 final exam.

12
00:00:29,030 --> 00:00:32,650
I like to think of the theme of
this problem as polymers.

13
00:00:32,650 --> 00:00:34,130
So that's the overarching
concept.

14
00:00:34,130 --> 00:00:36,130
But I'm going to give you some
things I think are important

15
00:00:36,130 --> 00:00:39,240
to review and to know before
actually meaningfully

16
00:00:39,240 --> 00:00:40,980
attempting this problem.

17
00:00:40,980 --> 00:00:44,370
So there's three things that I
that I sort of thought were

18
00:00:44,370 --> 00:00:45,080
very important.

19
00:00:45,080 --> 00:00:48,000
The first one is polymerization
processes.

20
00:00:48,000 --> 00:00:50,730
So we learned in class and in
the book as well that there's

21
00:00:50,730 --> 00:00:54,120
two ways that we've covered that
you can create a polymer.

22
00:00:54,120 --> 00:00:56,610
And that is through either
addition polymerization or

23
00:00:56,610 --> 00:00:58,520
condensation polymerization.

24
00:00:58,520 --> 00:01:01,150
And I'll talk about that
more in a second.

25
00:01:01,150 --> 00:01:03,770
The second thing you want to
know is basically molecular

26
00:01:03,770 --> 00:01:05,930
weight and how it applies
to polymers.

27
00:01:05,930 --> 00:01:09,150
And you want to know about
elastomers for this problem.

28
00:01:09,150 --> 00:01:10,660
If you don't know about
elastomers then you'll have

29
00:01:10,660 --> 00:01:12,370
trouble with the last
part of the problem.

30
00:01:12,370 --> 00:01:15,000
So that's kind of what
I would review.

31
00:01:15,000 --> 00:01:17,400
And then once you've got that
under your belt give the

32
00:01:17,400 --> 00:01:18,990
problem a try.

33
00:01:18,990 --> 00:01:20,060
So we're going to go
and we're going to

34
00:01:20,060 --> 00:01:21,310
start the problem now.

35
00:01:23,600 --> 00:01:27,850
We're given in the problem the
6-aminohexanoic acid, which

36
00:01:27,850 --> 00:01:29,560
I've drawn here.

37
00:01:29,560 --> 00:01:32,170
And we're also given at the
beginning of the problem the

38
00:01:32,170 --> 00:01:34,300
structure of nylon 6.

39
00:01:34,300 --> 00:01:38,130
This is the actual reaction
that's used to create nylon.

40
00:01:38,130 --> 00:01:41,300
So what I'm going to do is
I'm going to show you--

41
00:01:41,300 --> 00:01:43,990
or ask the question of how
do we create nylon from

42
00:01:43,990 --> 00:01:46,850
6-aminohexanoic acid.

43
00:01:46,850 --> 00:01:50,350
And that's actually going to
answer part A and part B to

44
00:01:50,350 --> 00:01:52,350
this problem.

45
00:01:52,350 --> 00:01:54,410
So to create a polymer--

46
00:01:54,410 --> 00:01:57,060
in this case we're talking about
the polymer nylon 6--

47
00:01:57,060 --> 00:01:59,940
you actually have to add
together many mers.

48
00:01:59,940 --> 00:02:03,900
So merge is the term we used
to denote the single unit

49
00:02:03,900 --> 00:02:09,380
which is repeated n times
to create the poly mer--

50
00:02:09,380 --> 00:02:10,410
polymer.

51
00:02:10,410 --> 00:02:16,180
So in this case the mer, the
individual unit of nylon 6, is

52
00:02:16,180 --> 00:02:18,650
6-aminohexanoic acid.

53
00:02:18,650 --> 00:02:19,590
And that's this.

54
00:02:19,590 --> 00:02:21,920
That's the same thing
right there.

55
00:02:21,920 --> 00:02:23,990
So we're going to add these
together and we're going to

56
00:02:23,990 --> 00:02:26,720
start creating our long
chain of nylon 6.

57
00:02:26,720 --> 00:02:30,440
Remember, nylon 6 a polymer is
a really, really long chain.

58
00:02:30,440 --> 00:02:33,040
Think of it as spaghetti,
very long spaghetti.

59
00:02:33,040 --> 00:02:35,620
It isn't just two molecules
that react.

60
00:02:35,620 --> 00:02:37,680
So let's just start somewhere.

61
00:02:37,680 --> 00:02:38,750
It's got to begin somewhere.

62
00:02:38,750 --> 00:02:40,870
You have to have two molecules
at some point in the beginning

63
00:02:40,870 --> 00:02:42,590
reacting with each other.

64
00:02:42,590 --> 00:02:44,460
So let's look at our
two molecules of

65
00:02:44,460 --> 00:02:45,970
6-aminohexanoic acid--

66
00:02:45,970 --> 00:02:49,340
I have to keep looking back
at how to say that--

67
00:02:49,340 --> 00:02:51,980
so let's take a look and we have
to think about now our

68
00:02:51,980 --> 00:02:55,260
two possible processes or routes
towards polymerization.

69
00:02:55,260 --> 00:02:57,860
There's addition and there's
condensation.

70
00:02:57,860 --> 00:03:01,230
Now addition, as you probably
read and heard, requires there

71
00:03:01,230 --> 00:03:04,550
to be a double bond present
between two carbon atoms. The

72
00:03:04,550 --> 00:03:07,160
reason for this is because
usually have a free radical

73
00:03:07,160 --> 00:03:09,830
coming in, which will
then initiate.

74
00:03:09,830 --> 00:03:12,950
That's why oftentimes the free
radical molecule or free

75
00:03:12,950 --> 00:03:14,690
radical provider is called
the initiator.

76
00:03:14,690 --> 00:03:18,650
You need an initiator to come
in to break that double bond

77
00:03:18,650 --> 00:03:20,330
and then create another
free radical.

78
00:03:20,330 --> 00:03:23,260
Which then lets the process
continue along in

79
00:03:23,260 --> 00:03:24,810
a chain like that.

80
00:03:24,810 --> 00:03:27,890
If we look at our molecule here,
we don't actually have

81
00:03:27,890 --> 00:03:30,280
any double bonds between two
carbon atoms. We have a double

82
00:03:30,280 --> 00:03:33,630
bond with an oxygen but that's
not sufficient for an

83
00:03:33,630 --> 00:03:36,300
addition-type reaction.

84
00:03:36,300 --> 00:03:39,720
For a condensation reaction,
what that basically implies is

85
00:03:39,720 --> 00:03:44,840
two mer units, or two things
coming together to react and

86
00:03:44,840 --> 00:03:46,630
they give off a byproduct.

87
00:03:46,630 --> 00:03:49,390
So that's how I remember
condensation, very often the

88
00:03:49,390 --> 00:03:50,660
byproduct is water.

89
00:03:50,660 --> 00:03:55,200
You can have other byproducts,
like HCl or any other sort of

90
00:03:55,200 --> 00:03:57,160
small molecules can
be given off.

91
00:03:57,160 --> 00:04:00,260
But most times what we'll see
in 3091 will be water given

92
00:04:00,260 --> 00:04:02,620
off in condensation, so it's
sort of intuitive to call it

93
00:04:02,620 --> 00:04:03,990
condensation.

94
00:04:03,990 --> 00:04:07,570
In this problem, if we look at
this, we have a molecule that

95
00:04:07,570 --> 00:04:11,090
has the Hs on one side and has
Os on the other side, we can

96
00:04:11,090 --> 00:04:13,830
actually almost see this
immediately as being a

97
00:04:13,830 --> 00:04:15,170
condensation reaction.

98
00:04:15,170 --> 00:04:18,010
What's going to happen is we're
going to have this O

99
00:04:18,010 --> 00:04:19,360
reacting with the positive
end of this

100
00:04:19,360 --> 00:04:21,020
molecule, which has Hs.

101
00:04:21,020 --> 00:04:23,450
And we're going to have an H2O
liberated and given off.

102
00:04:23,450 --> 00:04:24,940
We're going to have the
new molecule formed.

103
00:04:24,940 --> 00:04:26,760
Let me draw the molecule
for you.

104
00:04:26,760 --> 00:04:28,010
Let me write it out.

105
00:04:59,830 --> 00:05:02,490
So we've just begun forming
our polymer and this is a

106
00:05:02,490 --> 00:05:04,120
polymer which has an n of 2.

107
00:05:04,120 --> 00:05:06,180
It has 2 mer units
building it.

108
00:05:06,180 --> 00:05:08,350
Notice I've kept
the ends here.

109
00:05:08,350 --> 00:05:11,090
The positive and the
negative here.

110
00:05:11,090 --> 00:05:14,030
In reality what's going to
happen is we have a big vat of

111
00:05:14,030 --> 00:05:17,940
this 6-aminohexanoic
acid and they're

112
00:05:17,940 --> 00:05:18,940
going to keep reacting.

113
00:05:18,940 --> 00:05:21,960
So we might have another one of
these molecules float over

114
00:05:21,960 --> 00:05:23,790
and react with this O.

115
00:05:23,790 --> 00:05:26,800
Or conversely, we could have
another one of these molecules

116
00:05:26,800 --> 00:05:29,150
come over and react
with the H.

117
00:05:29,150 --> 00:05:30,960
So this thing is going
to keep building.

118
00:05:30,960 --> 00:05:33,410
And the way these polymerization
processes begin

119
00:05:33,410 --> 00:05:37,470
is the control of some parameter
of the system.

120
00:05:37,470 --> 00:05:39,570
It could be temperature,
pressure you can add something

121
00:05:39,570 --> 00:05:40,990
in to sort of initiate it.

122
00:05:40,990 --> 00:05:43,000
But that's how this
is going to start.

123
00:05:43,000 --> 00:05:45,800
So we've actually sort of
answered part a and b.

124
00:05:45,800 --> 00:05:48,890
We've come to the conclusion
that this is obviously a

125
00:05:48,890 --> 00:05:50,340
condensation reaction.

126
00:05:50,340 --> 00:05:51,965
Because we're going
to give off--

127
00:05:51,965 --> 00:05:56,570
I left that out there, see
if you guys caught it--

128
00:05:56,570 --> 00:05:58,460
H2O.

129
00:05:58,460 --> 00:06:04,070
So we're losing this O and
two of these Hs and

130
00:06:04,070 --> 00:06:05,320
we're forming water.

131
00:06:05,320 --> 00:06:06,880
And that's the byproduct.

132
00:06:06,880 --> 00:06:09,080
And a byproduct immediately
should tell you we've got

133
00:06:09,080 --> 00:06:10,390
condensation going on.

134
00:06:10,390 --> 00:06:12,720
So condensation polymerization,
part A.

135
00:06:12,720 --> 00:06:16,160
Part B, we've actually already
done to sort of logic out the

136
00:06:16,160 --> 00:06:17,410
answer to part A.

137
00:06:17,410 --> 00:06:19,420
This is the answer to part B.

138
00:06:19,420 --> 00:06:20,660
Part B is just the reaction.

139
00:06:20,660 --> 00:06:22,150
I'll read it very
specifically.

140
00:06:22,150 --> 00:06:24,380
Write the reaction that converts
two molecules of

141
00:06:24,380 --> 00:06:28,800
6-aminohexanoic acid into
a dimer of nylon 6.

142
00:06:28,800 --> 00:06:31,350
So we have two molecules
forming the dimer.

143
00:06:31,350 --> 00:06:33,500
You are going to have trimer,
and it goes on and on.

144
00:06:33,500 --> 00:06:36,420
The most common mistake on this
problem was to give us

145
00:06:36,420 --> 00:06:39,530
the full repeating units.

146
00:06:39,530 --> 00:06:41,400
Let me just show you what
that would look like.

147
00:06:41,400 --> 00:06:42,290
And then we'll move on
with the problem.

148
00:06:42,290 --> 00:06:46,000
So the most common mistake on
this problem was to not have

149
00:06:46,000 --> 00:06:46,990
these end units.

150
00:06:46,990 --> 00:06:50,070
And instead say, oh it's created
this huge, long chain.

151
00:06:50,070 --> 00:06:51,720
So I'm going to write
it as follows.

152
00:06:57,820 --> 00:07:01,940
And this is the symbol to
imply that it repeats.

153
00:07:01,940 --> 00:07:03,190
Likewise over here.

154
00:07:09,340 --> 00:07:10,950
So people would give us this.

155
00:07:10,950 --> 00:07:12,430
And that's not correct.

156
00:07:12,430 --> 00:07:14,070
And the reason that's a problem
is because not only do

157
00:07:14,070 --> 00:07:15,690
you lose points on this
part, you also lose

158
00:07:15,690 --> 00:07:16,880
points on the next part.

159
00:07:16,880 --> 00:07:21,180
So part C is now asking us to
calculate the molecular weight

160
00:07:21,180 --> 00:07:23,190
of a molecule given
a certain n.

161
00:07:23,190 --> 00:07:25,160
n is the degree of
polymerization.

162
00:07:25,160 --> 00:07:28,140
So in this case, n equals
2, we've got a dimer.

163
00:07:28,140 --> 00:07:31,680
In part C, we have n equals--

164
00:07:31,680 --> 00:07:33,230
surprisingly--

165
00:07:33,230 --> 00:07:38,760
3,091 You'll see that's a
recurring theme in this class.

166
00:07:38,760 --> 00:07:42,420
So we have n equals 3,091 And
the question is, how do we

167
00:07:42,420 --> 00:07:43,890
approach the molecular
weight problem?

168
00:07:43,890 --> 00:07:48,220
Well we're told that we have
3,091 one of these mer units

169
00:07:48,220 --> 00:07:50,710
making up this polymer chain.

170
00:07:50,710 --> 00:07:51,950
So let me just write
this down.

171
00:07:51,950 --> 00:07:54,950
We're going to form
an equation.

172
00:07:54,950 --> 00:07:58,640
If we take the mass of the full
chain and divide it by

173
00:07:58,640 --> 00:08:02,790
the mass of a single mer unit
we should be able to extract

174
00:08:02,790 --> 00:08:04,280
the number of units
in the chain.

175
00:08:04,280 --> 00:08:06,420
So let me write that
out for you.

176
00:08:06,420 --> 00:08:09,820
So the total molecular weight
of the molecule, divided by

177
00:08:09,820 --> 00:08:13,580
the weight of a particular
mer unit.

178
00:08:13,580 --> 00:08:16,755
OK so we're going to
put that as mer.

179
00:08:19,460 --> 00:08:20,710
And so this is easy.

180
00:08:20,710 --> 00:08:22,750
Let's first identify what
our mer unit is.

181
00:08:22,750 --> 00:08:24,340
And this is why it was easy get

182
00:08:24,340 --> 00:08:25,390
tripped up on this problem.

183
00:08:25,390 --> 00:08:27,530
Because if you made a mistake
on the part B, you have

184
00:08:27,530 --> 00:08:28,950
trouble on part C.

185
00:08:28,950 --> 00:08:30,710
What is our mer unit?

186
00:08:30,710 --> 00:08:33,960
So in our mer unit, what we're
talking about is a chain which

187
00:08:33,960 --> 00:08:40,360
has 3,091 of these linked
pieces here.

188
00:08:40,360 --> 00:08:41,580
So let's look at this.

189
00:08:41,580 --> 00:08:42,460
What do we have?

190
00:08:42,460 --> 00:08:43,490
Here's our mer unit.

191
00:08:43,490 --> 00:08:44,740
Let me circle it.

192
00:08:47,350 --> 00:08:51,700
We have 6 carbons.

193
00:08:51,700 --> 00:08:56,510
We have 11 hydrogens,
1 nitrogen and 1

194
00:08:56,510 --> 00:08:58,650
oxygen in this mer unit.

195
00:08:58,650 --> 00:09:00,860
We're not going to take the
full, complete end unit.

196
00:09:00,860 --> 00:09:01,970
We're not counting this O.

197
00:09:01,970 --> 00:09:03,990
We're not counting those 2 Hs.

198
00:09:03,990 --> 00:09:08,630
We're dropping off 18 grams
per reaction into water.

199
00:09:08,630 --> 00:09:09,600
So this is our mere unit.

200
00:09:09,600 --> 00:09:12,880
Let's calculate the mass
of our mer unit.

201
00:09:12,880 --> 00:09:14,472
So it's going to be--

202
00:09:14,472 --> 00:09:17,890
let me write this here--

203
00:09:17,890 --> 00:09:20,260
we're looking for molecular
weight.

204
00:09:20,260 --> 00:09:22,220
We're going to divide that by
the mass of the mer unit.

205
00:09:22,220 --> 00:09:26,200
Let me just write out the full
line of what it would be.

206
00:09:26,200 --> 00:09:31,830
Approximately 6 times
12 plus 11 times 1.

207
00:09:31,830 --> 00:09:34,610
So this is 6 carbons, times
the mass of carbon.

208
00:09:34,610 --> 00:09:36,890
11 hydrogens times the
mass of hydrogen.

209
00:09:36,890 --> 00:09:40,450
We're going to have 1 oxygen
times the mass of oxygen.

210
00:09:40,450 --> 00:09:42,660
And we're going to have
the nitrogen as well.

211
00:09:42,660 --> 00:09:43,940
So let me add that down here.

212
00:09:43,940 --> 00:09:46,760
1 nitrogen times the
mass of nitrogen.

213
00:09:46,760 --> 00:09:47,280
I rounded.

214
00:09:47,280 --> 00:09:47,730
That's OK.

215
00:09:47,730 --> 00:09:50,590
As long as you get
the idea right.

216
00:09:50,590 --> 00:09:52,000
So now we can easily
just solve for

217
00:09:52,000 --> 00:09:53,290
the molecular weight.

218
00:09:53,290 --> 00:09:57,210
And we'll find that molecular
weight in this problem will be

219
00:09:57,210 --> 00:10:05,270
equal to 3.5 times 10 to the
fifth grams per mole.

220
00:10:10,310 --> 00:10:11,870
There's another way to do
this problem, actually.

221
00:10:11,870 --> 00:10:15,680
And what you can do is you
can calculate n times

222
00:10:15,680 --> 00:10:17,860
the number of this--

223
00:10:17,860 --> 00:10:20,170
this particular molecule--

224
00:10:20,170 --> 00:10:24,980
and you can subtract
off 3,090 orders.

225
00:10:24,980 --> 00:10:27,500
18 grams. 3,090 times
eighteen.

226
00:10:27,500 --> 00:10:28,630
You subtract that off.

227
00:10:28,630 --> 00:10:32,940
Think about a little bit why
it's 3,090 and not 3,091.

228
00:10:32,940 --> 00:10:35,160
So that's just maybe a
brain teaser for you.

229
00:10:35,160 --> 00:10:37,320
That is the answer to part C.

230
00:10:37,320 --> 00:10:40,730
And now part D asks us if we're
able to convert this

231
00:10:40,730 --> 00:10:41,920
into an elastomer.

232
00:10:41,920 --> 00:10:44,010
So this is where it's really
required that you understand

233
00:10:44,010 --> 00:10:46,590
what an elastomer is and what
that implies and what the

234
00:10:46,590 --> 00:10:47,820
structure looks like.

235
00:10:47,820 --> 00:10:49,640
So an elastomer--

236
00:10:49,640 --> 00:10:52,240
and I sort of paraphrased this
from the book and added my own

237
00:10:52,240 --> 00:10:56,260
thing to it-- is basically a
randomly oriented amorphous

238
00:10:56,260 --> 00:10:58,960
polymer with some cross-linking
such that you

239
00:10:58,960 --> 00:11:01,960
have the ability to move the
chains but not slide them

240
00:11:01,960 --> 00:11:03,600
completely over each other.

241
00:11:03,600 --> 00:11:05,740
So in order to have an elastomer
you must have

242
00:11:05,740 --> 00:11:06,680
cross-linking.

243
00:11:06,680 --> 00:11:07,970
In order to have cross-linking,

244
00:11:07,970 --> 00:11:09,090
what must you have?

245
00:11:09,090 --> 00:11:11,020
Well from lecture and from
the book we know that to

246
00:11:11,020 --> 00:11:14,330
cross-link you must have double
bonds in your carbons.

247
00:11:14,330 --> 00:11:15,940
So you must have 2 carbons--

248
00:11:15,940 --> 00:11:17,020
going back over here--

249
00:11:17,020 --> 00:11:18,550
which are double-bonded
together.

250
00:11:18,550 --> 00:11:19,830
And why is that?

251
00:11:19,830 --> 00:11:22,200
Because what happens is those
double bonds will be broken by

252
00:11:22,200 --> 00:11:26,120
some initiator element-- many
times we'll have sulfur--

253
00:11:26,120 --> 00:11:29,920
will come in, break the double
bond and then you'll have

254
00:11:29,920 --> 00:11:30,910
links forming between things.

255
00:11:30,910 --> 00:11:33,250
So let me actually give you
real-life example of this so

256
00:11:33,250 --> 00:11:35,070
you can see what I'm
talking about.

257
00:11:35,070 --> 00:11:38,940
We're going to show disulfide
bridges bounding and creating

258
00:11:38,940 --> 00:11:40,455
cross-links in a molecule.

259
00:11:55,320 --> 00:11:57,310
Something we're very familiar
with is rubber.

260
00:11:57,310 --> 00:11:59,100
And we're also very familiar
with car tires.

261
00:11:59,100 --> 00:12:02,530
The big difference between
those two things is that

262
00:12:02,530 --> 00:12:05,470
rubber has vulcanized Which
means we're actually putting

263
00:12:05,470 --> 00:12:08,520
sulphur into it to create a
different type of polymer.

264
00:12:08,520 --> 00:12:12,080
We're looking at a cross-linked,
much stronger

265
00:12:12,080 --> 00:12:14,060
rubber which we use
on our car tires.

266
00:12:14,060 --> 00:12:16,550
So polyisoprene looks
something like this.

267
00:12:56,490 --> 00:12:59,520
You should be familiar with
this notation by now.

268
00:12:59,520 --> 00:13:05,100
We have this denotes
it repeats.

269
00:13:05,100 --> 00:13:06,290
We have our double
bonds, we have

270
00:13:06,290 --> 00:13:07,620
our carbons and hydrogens.

271
00:13:07,620 --> 00:13:09,770
This is polyisoprene.

272
00:13:09,770 --> 00:13:11,250
And this is what we're
going to add sulphur

273
00:13:11,250 --> 00:13:12,430
to vulcanize rubber.

274
00:13:12,430 --> 00:13:14,750
We're going to create
vulcanized rubber.

275
00:13:14,750 --> 00:13:19,300
sulphur generally actually
looks, it's a ring of 8

276
00:13:19,300 --> 00:13:25,740
sulphur atoms. We'll then
add it to rubber,

277
00:13:25,740 --> 00:13:27,230
maybe heat it up mixed.

278
00:13:27,230 --> 00:13:30,910
And you'll make what you're
used to on car tires.

279
00:13:30,910 --> 00:13:33,040
So what's actually happening
here is that you can see we

280
00:13:33,040 --> 00:13:34,930
have this double bond
between carbons.

281
00:13:34,930 --> 00:13:37,970
The sulphur's going to come in,
it's going to react with

282
00:13:37,970 --> 00:13:42,480
this double bond, and is
actually going to pull it off.

283
00:13:42,480 --> 00:13:44,430
And it might form a
chain like that.

284
00:13:44,430 --> 00:13:47,480
And then this sulfur will then
connect to another one of

285
00:13:47,480 --> 00:13:49,820
these polyisoprene molecules
that was

286
00:13:49,820 --> 00:13:51,390
originally double bonded.

287
00:13:51,390 --> 00:13:53,630
And I'm not going to draw
the rest of it out.

288
00:13:53,630 --> 00:13:56,900
And it's going to react, kill
this double bond, and it's

289
00:13:56,900 --> 00:13:57,870
going to connect it.

290
00:13:57,870 --> 00:14:00,100
So basically what's happened
in this process of forming

291
00:14:00,100 --> 00:14:04,790
sulfide bridges is you've got
this polymer, polyisoprene,

292
00:14:04,790 --> 00:14:08,260
connecting to this polymer,
polyisoprene, and you have

293
00:14:08,260 --> 00:14:09,720
cross-linking going on.

294
00:14:09,720 --> 00:14:13,910
And that's what we would need
to have in our case for the

295
00:14:13,910 --> 00:14:18,185
nylon 6 in order to get an
elastomer, And because nylon

296
00:14:18,185 --> 00:14:21,840
6, because our mer unit,
6-aminohexanoic acid doesn't

297
00:14:21,840 --> 00:14:24,750
have double bonds, we
can't break them.

298
00:14:24,750 --> 00:14:25,850
We can't network.

299
00:14:25,850 --> 00:14:27,380
We can't cross-link.

300
00:14:27,380 --> 00:14:29,460
And therefore we can't
make an elastomer.

301
00:14:29,460 --> 00:14:31,010
So the answer to
this problem--

302
00:14:31,010 --> 00:14:33,440
in a very long-winded manner--

303
00:14:33,440 --> 00:14:34,320
is no.

304
00:14:34,320 --> 00:14:38,060
You cannot create an elastomer
given that mer unit.