1
00:00:16,500 --> 00:00:20,416
Well, I got to show you
this spider because--

2
00:00:20,416 --> 00:00:22,250
and if you're interested,
Professor Bueller

3
00:00:22,250 --> 00:00:24,700
does some wonderful
work on spider silk--

4
00:00:24,700 --> 00:00:29,166
because I think this is a
great example of something

5
00:00:29,166 --> 00:00:35,300
that nature can do that gives us
a sense of how far away we are.

6
00:00:35,300 --> 00:00:41,433
Like I said, we're very proud
of this, and we want to do more.

7
00:00:41,433 --> 00:00:44,333
And so we take our two mers,
and we mix them together,

8
00:00:44,333 --> 00:00:45,866
and we make branches,
and maybe we're

9
00:00:45,866 --> 00:00:48,100
going to try to add a third.

10
00:00:48,100 --> 00:00:51,633
Meanwhile, nature has had a lot
more flexibility and a lot more

11
00:00:51,633 --> 00:00:52,350
time.

12
00:00:52,350 --> 00:00:53,066
What can it do?

13
00:00:53,066 --> 00:00:55,083
Well, here's spider silk.

14
00:00:55,083 --> 00:00:56,850
Now, this is a spider.

15
00:00:56,850 --> 00:01:01,750
Spider is an incredible
polymer synthesis machine.

16
00:01:01,750 --> 00:01:04,116
It's an incredible
polymer synthesis machine.

17
00:01:04,116 --> 00:01:06,216
And here it is weaving
a web, and I love this--

18
00:01:06,216 --> 00:01:06,583
[MUSIC PLAYING]

19
00:01:06,583 --> 00:01:07,950
--because I think it's so cool.

20
00:01:07,950 --> 00:01:10,050
OK, there's music, I guess.

21
00:01:10,050 --> 00:01:12,250
I forgot about that,
and there it is.

22
00:01:12,250 --> 00:01:13,083
Now watch.

23
00:01:13,083 --> 00:01:16,700
Out of here, this is
the back of the spider.

24
00:01:16,700 --> 00:01:18,466
There it is right there.

25
00:01:18,466 --> 00:01:19,750
It's making protein.

26
00:01:19,750 --> 00:01:22,550
That's called spider silk,
but these are proteins.

27
00:01:22,550 --> 00:01:23,700
These are polymers.

28
00:01:23,700 --> 00:01:27,000
It is doing condensation
polymerization right there,

29
00:01:27,000 --> 00:01:29,500
and then there's all sorts of
structural stuff that it does.

30
00:01:29,500 --> 00:01:30,000
Right?

31
00:01:30,000 --> 00:01:31,200
It's got a specialized hook.

32
00:01:31,200 --> 00:01:32,100
It knows how to step.

33
00:01:32,100 --> 00:01:33,183
It creates-- look at that.

34
00:01:33,183 --> 00:01:35,216
There's a branch place
where it knows to put it.

35
00:01:35,216 --> 00:01:35,716
Right?

36
00:01:35,716 --> 00:01:39,066
It's already created the glue.

37
00:01:39,066 --> 00:01:42,483
So not only is it putting
this spider silk out there,

38
00:01:42,483 --> 00:01:45,515
but it can put other
types of polymer

39
00:01:45,515 --> 00:01:46,700
depending on what it needs.

40
00:01:46,700 --> 00:01:49,515
Does it need something
really sticky, less sticky?

41
00:01:49,515 --> 00:01:50,050
Right?

42
00:01:50,050 --> 00:01:51,550
And so there it is
weaving its web,

43
00:01:51,550 --> 00:01:54,366
and it's generating
this polymer on the fly.

44
00:01:54,366 --> 00:01:56,466
It's doing condensation
polymerization.

45
00:01:56,466 --> 00:01:58,800
Now a couple properties
about spider silk.

46
00:01:58,800 --> 00:02:01,850
OK, so here we go.

47
00:02:01,850 --> 00:02:02,466
Let's see.

48
00:02:02,466 --> 00:02:11,100
So spider silk, this is just one
example of what nature can do.

49
00:02:11,100 --> 00:02:13,100
It's five times
stronger than steel.

50
00:02:18,700 --> 00:02:21,066
Remember the mechanical
strength chart,

51
00:02:21,066 --> 00:02:23,000
nothing was stronger than steel.

52
00:02:23,000 --> 00:02:25,900
Spider silk is five
times stronger.

53
00:02:25,900 --> 00:02:30,500
Just to give you sense, the
example, I found that I like.

54
00:02:30,500 --> 00:02:33,516
If you had a spider silk
that was a pencil width,

55
00:02:33,516 --> 00:02:36,866
and you made a strand, it would
stop a Boeing 747 in midair.

56
00:02:36,866 --> 00:02:39,100
That's how strong it is.

57
00:02:39,100 --> 00:02:41,766
Oh, it keeps strength--

58
00:02:41,766 --> 00:02:53,400
here's another thing-- below
40 degrees C. We can't do that.

59
00:02:53,400 --> 00:02:56,433
Just take a rubber ball and put
it at that low of a temperature

60
00:02:56,433 --> 00:02:57,300
and try to bounce it.

61
00:02:57,300 --> 00:02:58,666
It's going to shatter.

62
00:02:58,666 --> 00:02:59,216
Right?

63
00:02:59,216 --> 00:03:02,916
Spider silk can keep that
strength and not break.

64
00:03:02,916 --> 00:03:06,450
Its elastic, so it's got--

65
00:03:06,450 --> 00:03:11,216
throughout all of this, it's
got an elastic property of 4x,

66
00:03:11,216 --> 00:03:13,683
so it can be stretched to four
times its original strength.

67
00:03:17,666 --> 00:03:19,216
Compare that with nitrile.

68
00:03:19,216 --> 00:03:22,650
Nitrile rubber could
also go to very, very

69
00:03:22,650 --> 00:03:25,916
high elastic elongation.

70
00:03:25,916 --> 00:03:26,416
All right?

71
00:03:26,416 --> 00:03:29,100
So if you go back to nitrile--

72
00:03:29,100 --> 00:03:30,950
here it is in the table.

73
00:03:30,950 --> 00:03:32,850
We're very happy with
this, but this only

74
00:03:32,850 --> 00:03:35,500
had two monomers to play with.

75
00:03:35,500 --> 00:03:36,050
Right?

76
00:03:36,050 --> 00:03:38,033
We played with two monomers,
and we got to here,

77
00:03:38,033 --> 00:03:41,083
and look at the sacrifice
in the strength.

78
00:03:41,083 --> 00:03:43,600
Look at how much we had
to sacrifice strength.

79
00:03:43,600 --> 00:03:45,416
Spiders don't have to do that.

80
00:03:45,416 --> 00:03:48,983
Here's the last one.

81
00:03:48,983 --> 00:03:56,866
Fully recycles-- now the
thing is that this is actually

82
00:03:56,866 --> 00:03:58,066
kind of incredible.

83
00:03:58,066 --> 00:04:01,300
Spider webs get dusty.

84
00:04:01,300 --> 00:04:03,833
They lose their stickiness.

85
00:04:03,833 --> 00:04:07,800
So many spiders know
this and just simply

86
00:04:07,800 --> 00:04:10,483
have to weave a
new web every day,

87
00:04:10,483 --> 00:04:12,866
but they don't leave
the old web there.

88
00:04:12,866 --> 00:04:18,065
They actually eat it, and
they fully recycle it, fully.

89
00:04:18,065 --> 00:04:18,565
Right?

90
00:04:18,565 --> 00:04:21,649
They eat the web, fully
recycle it, process it,

91
00:04:21,649 --> 00:04:25,550
have this condensation
polymerization work,

92
00:04:25,550 --> 00:04:27,582
and make a new one the next day.

93
00:04:27,582 --> 00:04:29,850
All right?

94
00:04:29,850 --> 00:04:33,366
So we don't come
close to this spider.

95
00:04:33,366 --> 00:04:38,066
We don't even come anywhere near
it in terms of where we are.

96
00:04:38,066 --> 00:04:40,416
Even though I gave you
all these wonderful things

97
00:04:40,416 --> 00:04:41,916
that we're doing
with engineering,

98
00:04:41,916 --> 00:04:45,266
we still have so far that
we could go if we could just

99
00:04:45,266 --> 00:04:47,816
figure out how nature works.

100
00:04:47,816 --> 00:04:49,416
OK?

101
00:04:49,416 --> 00:04:52,266
And this gets me to
what we do, and so I've

102
00:04:52,266 --> 00:04:54,216
got my "why this matters" now.

103
00:04:54,216 --> 00:04:58,950
And so a spider eats its
web, fully recycles it,

104
00:04:58,950 --> 00:05:00,700
spins a new web the next day.

105
00:05:00,700 --> 00:05:06,083
Here's what we do
with our polymers.

106
00:05:06,083 --> 00:05:09,133
I already talked
about the oceans.

107
00:05:09,133 --> 00:05:11,783
Here's what we do on land.

108
00:05:11,783 --> 00:05:13,083
These are tires.

109
00:05:13,083 --> 00:05:14,866
Now, tires are very
difficult to recycle.

110
00:05:14,866 --> 00:05:15,366
Why?

111
00:05:15,366 --> 00:05:17,733
Because they're too vulcanized.

112
00:05:17,733 --> 00:05:19,066
They've got too much cross-link.

113
00:05:19,066 --> 00:05:21,883
Remember, if the cross-link
density is too strong,

114
00:05:21,883 --> 00:05:27,416
which you need to make a tire,
then you can't recycle it.

115
00:05:27,416 --> 00:05:29,266
And in fact, what happens is--

116
00:05:29,266 --> 00:05:30,983
and there's a tire mound.

117
00:05:30,983 --> 00:05:32,750
Here's it is from a
satellite picture.

118
00:05:32,750 --> 00:05:34,582
Those are tires.

119
00:05:34,582 --> 00:05:35,633
Those are tire mounds.

120
00:05:35,633 --> 00:05:37,383
Here's what happens
when one catches fire.

121
00:05:37,383 --> 00:05:39,483
Here's what happens
when many catch fire.

122
00:05:39,483 --> 00:05:40,466
All right?

123
00:05:40,466 --> 00:05:45,016
It's actually a very hard fire
to control once they catch.

124
00:05:45,016 --> 00:05:47,266
But we don't really
know how to recycle them

125
00:05:47,266 --> 00:05:48,950
well yet.

126
00:05:48,950 --> 00:05:51,900
What can we do?

127
00:05:51,900 --> 00:05:55,082
On the science and engineering
side, the fact of the matter

128
00:05:55,082 --> 00:05:56,832
is there is a lot of
work to do, but there

129
00:05:56,832 --> 00:05:58,233
are promising directions.

130
00:05:58,233 --> 00:06:00,750
So I wanted to leave you
with a little bit of that,

131
00:06:00,750 --> 00:06:02,500
and I'm not going to
go into great detail.

132
00:06:02,500 --> 00:06:04,666
I just want to show you,
and there's references here

133
00:06:04,666 --> 00:06:05,233
you can look.

134
00:06:05,233 --> 00:06:07,666
This was published a couple
of years ago in Nature.

135
00:06:07,666 --> 00:06:12,650
One direction is in
self-healing polymers.

136
00:06:12,650 --> 00:06:14,250
This is a very
exciting direction.

137
00:06:14,250 --> 00:06:15,050
What can we do?

138
00:06:15,050 --> 00:06:18,183
Well, we can go away from
this whole single-use idea

139
00:06:18,183 --> 00:06:20,266
and make stuff last longer.

140
00:06:20,266 --> 00:06:20,766
All right?

141
00:06:20,766 --> 00:06:22,816
So that would be beneficial.

142
00:06:22,816 --> 00:06:25,300
Maybe not if it ends
up in the ocean,

143
00:06:25,300 --> 00:06:29,500
but in terms of just how long
we can use these materials.

144
00:06:29,500 --> 00:06:32,283
So one direction is, well,
you've got these polymer

145
00:06:32,283 --> 00:06:34,750
networks, and you incorporate
little gels, little beads

146
00:06:34,750 --> 00:06:37,650
in here, but the
beads don't open up

147
00:06:37,650 --> 00:06:40,300
until a crack comes along.

148
00:06:40,300 --> 00:06:41,883
So they're sensitive to a crack.

149
00:06:41,883 --> 00:06:45,033
And when they feel a crack in
the material, they open up,

150
00:06:45,033 --> 00:06:48,850
and they pour a healing
liquid that then solidifies.

151
00:06:48,850 --> 00:06:50,466
That's a self-healing
kind of approach.

152
00:06:50,466 --> 00:06:52,050
You could do that
at different scales,

153
00:06:52,050 --> 00:06:53,650
all the way down to the strand.

154
00:06:53,650 --> 00:06:55,016
You can do that
on larger scales.

155
00:06:55,016 --> 00:06:57,600
And here's a whole system
where there's actually

156
00:06:57,600 --> 00:07:00,933
this healing material being
flowed through a polymer

157
00:07:00,933 --> 00:07:04,600
structure, just like
arteries in our body.

158
00:07:04,600 --> 00:07:07,683
Again, always there to
try to heal the material.

159
00:07:07,683 --> 00:07:09,133
Right?

160
00:07:09,133 --> 00:07:12,300
Another direction is
in fully recovering.

161
00:07:12,300 --> 00:07:14,466
And again, I don't want to
go into full detail here.

162
00:07:14,466 --> 00:07:16,050
You can look up
some of this stuff.

163
00:07:16,050 --> 00:07:18,433
This was published last year.

164
00:07:18,433 --> 00:07:21,516
Can we take the
polymer and chemically

165
00:07:21,516 --> 00:07:25,016
decompose it all the
way back to the monomer?

166
00:07:25,016 --> 00:07:27,050
Can we go back to
where we started?

167
00:07:27,050 --> 00:07:29,866
Can we do what the spider does?

168
00:07:29,866 --> 00:07:30,366
Right?

169
00:07:30,366 --> 00:07:33,383
The answer is no, not today.

170
00:07:33,383 --> 00:07:36,750
But if we could,
that would open up

171
00:07:36,750 --> 00:07:39,832
a whole lot of
doors for recycling

172
00:07:39,832 --> 00:07:41,066
that are closed today.

173
00:07:41,066 --> 00:07:44,000
Can we do this in a
way that is efficient?

174
00:07:44,000 --> 00:07:45,200
Right?

175
00:07:45,200 --> 00:07:48,383
And then, another
direction of work

176
00:07:48,383 --> 00:07:50,033
that I think is
very important is

177
00:07:50,033 --> 00:07:54,016
in making thermosets so
heavily cross-linked so you

178
00:07:54,016 --> 00:07:56,183
get all the hardness and
all the properties you need

179
00:07:56,183 --> 00:07:59,033
of the polymer that's heavily
cross-linked, but easily

180
00:07:59,033 --> 00:08:00,716
breakable in the cross link.

181
00:08:00,716 --> 00:08:03,633
And there is good work
going on in this direction.

182
00:08:03,633 --> 00:08:06,800
Can we make
degradable thermosets?

183
00:08:06,800 --> 00:08:09,083
That's another really
important direction.

184
00:08:09,083 --> 00:08:11,583
And last, we should
be encouraging people,

185
00:08:11,583 --> 00:08:13,700
if you can't do any
of this, at least take

186
00:08:13,700 --> 00:08:16,433
the polymer out of the landfill
and make something with it.

187
00:08:16,433 --> 00:08:19,133
And there are projects-- you can
look at here, Waste Management

188
00:08:19,133 --> 00:08:22,016
Journal, in making
bricks out of polymers,

189
00:08:22,016 --> 00:08:24,433
incorporating them into
construction materials.

190
00:08:24,433 --> 00:08:24,933
Right?

191
00:08:24,933 --> 00:08:29,133
These are important directions,
and we need a lot more

192
00:08:29,133 --> 00:08:31,700
hopefully in the very near term.