1 00:00:16,315 --> 00:00:19,486 we will be talking about a new topic today. 2 00:00:19,486 --> 00:00:22,389 And that's polymers. 3 00:00:22,389 --> 00:00:25,725 And we're going to start by talking about-- 4 00:00:25,725 --> 00:00:28,294 what I want to do is cover two ways 5 00:00:28,294 --> 00:00:31,731 that we humans make polymers. 6 00:00:31,731 --> 00:00:35,802 And the first way has to do with something called the radical. 7 00:00:35,802 --> 00:00:39,039 So that's where I want to start our story. 8 00:00:39,039 --> 00:00:42,375 And what is a radical? 9 00:00:42,375 --> 00:00:51,251 Well, a radical is a molecule that has 10 00:00:51,251 --> 00:00:54,621 one or more unpaired electrons. 11 00:00:54,621 --> 00:01:05,432 So one or more unpaired electrons. 12 00:01:05,432 --> 00:01:08,568 But as you can imagine, if I've got an unpaired electron, 13 00:01:08,568 --> 00:01:11,905 it's kind of like a broken bond. 14 00:01:11,905 --> 00:01:13,239 It's kind of like a broken bond. 15 00:01:13,239 --> 00:01:14,207 That's a radical. 16 00:01:14,207 --> 00:01:17,343 And you could also imagine that a broken bond 17 00:01:17,343 --> 00:01:20,513 wants to not be broken. 18 00:01:20,513 --> 00:01:24,717 So it's going to try to find something to bond to. 19 00:01:24,717 --> 00:01:28,388 That's why we've got radicals all in us all the time. 20 00:01:28,388 --> 00:01:30,623 Sometimes they're important, but sometimes they 21 00:01:30,623 --> 00:01:34,227 can cause a lot of harm. 22 00:01:34,227 --> 00:01:36,628 And that's why if you eat blueberries, then 23 00:01:36,628 --> 00:01:40,633 you get these things called antioxidants. 24 00:01:40,633 --> 00:01:43,336 And antioxidants, that's just one of many, many types 25 00:01:43,336 --> 00:01:44,404 of antioxidants. 26 00:01:44,404 --> 00:01:45,238 What do they do? 27 00:01:45,238 --> 00:01:46,973 They go and they give these radicals 28 00:01:46,973 --> 00:01:51,911 what they need, what they're looking for, an electron. 29 00:01:51,911 --> 00:01:53,279 They give them an electron. 30 00:01:53,279 --> 00:01:55,048 And they don't mind. 31 00:01:55,048 --> 00:01:57,317 They don't become radical themselves. 32 00:01:57,317 --> 00:02:01,488 They just simply stop the radical from being radical. 33 00:02:01,488 --> 00:02:02,555 Now, why does this matter? 34 00:02:02,555 --> 00:02:05,658 Well, we're going to see what that means for polymers. 35 00:02:05,658 --> 00:02:06,759 But let's make a radical. 36 00:02:06,759 --> 00:02:09,228 So imagine-- and I'm going to go Lewis on us, 37 00:02:09,228 --> 00:02:11,297 because I want to see the electrons. 38 00:02:11,297 --> 00:02:12,232 I'm going to go Lewis. 39 00:02:12,232 --> 00:02:14,901 So imagine I've got methane. 40 00:02:14,901 --> 00:02:20,039 Well, methane looks like this, nice and happy. 41 00:02:20,039 --> 00:02:21,040 Oh, the octet. 42 00:02:24,310 --> 00:02:28,414 But now I introduced a chlorine atom. 43 00:02:28,414 --> 00:02:30,316 So I've got now chlorine. 44 00:02:30,316 --> 00:02:34,320 And chlorine is hungry. 45 00:02:34,320 --> 00:02:37,924 Chlorine wants to fill its octet by itself. 46 00:02:40,460 --> 00:02:41,494 And so what does it do? 47 00:02:41,494 --> 00:02:43,730 It's like, well, I'm powerful. 48 00:02:43,730 --> 00:02:44,230 I'm strong. 49 00:02:44,230 --> 00:02:46,432 I'm just going to grab from methane. 50 00:02:46,432 --> 00:02:48,735 It sees methane, and it's like, OK, 51 00:02:48,735 --> 00:02:51,804 you give me one of your electrons. 52 00:02:51,804 --> 00:02:52,972 How about that is a deal? 53 00:02:55,675 --> 00:02:57,877 And here we go. 54 00:02:57,877 --> 00:02:59,946 And here we go. 55 00:02:59,946 --> 00:03:03,283 And it takes it in the form of the hydrogen. 56 00:03:03,283 --> 00:03:09,022 And so we got this like this, and like this. 57 00:03:09,022 --> 00:03:12,892 Oh, the chlorine got really happy, 58 00:03:12,892 --> 00:03:16,296 but look at what happened to the methane. 59 00:03:16,296 --> 00:03:20,233 It lost an electron and a hydrogen with it, 60 00:03:20,233 --> 00:03:23,870 and it has an unpaired electron. 61 00:03:23,870 --> 00:03:25,371 That electron is not happy. 62 00:03:25,371 --> 00:03:29,642 I mean, it just wants to bond to something. 63 00:03:29,642 --> 00:03:30,143 That's all. 64 00:03:30,143 --> 00:03:32,245 You can't blame it. 65 00:03:32,245 --> 00:03:34,914 Don't we all want that? 66 00:03:34,914 --> 00:03:40,053 The problem is that this really needs it badly. 67 00:03:40,053 --> 00:03:41,754 And so this is called-- 68 00:03:41,754 --> 00:03:44,190 so what we did is we took chlorine, 69 00:03:44,190 --> 00:03:47,293 and we combined it with methane. 70 00:03:47,293 --> 00:03:50,797 And we made what's called a methyl radical. 71 00:03:50,797 --> 00:03:52,932 So this is called-- 72 00:03:52,932 --> 00:03:54,234 that's called a free radical. 73 00:04:00,473 --> 00:04:03,176 Or in this case, it's methyl, because that's 74 00:04:03,176 --> 00:04:04,477 what the chemistry is. 75 00:04:04,477 --> 00:04:05,812 It's a methyl radical. 76 00:04:05,812 --> 00:04:09,682 As we'll see, you can make radicals out of lots of stuff. 77 00:04:09,682 --> 00:04:11,884 Just take a hydrogen and an electron 78 00:04:11,884 --> 00:04:14,687 that have a free unpaired electron left, 79 00:04:14,687 --> 00:04:16,822 and it's a radical. 80 00:04:16,822 --> 00:04:24,664 I could start with ethane and make an ethyl radical, C2H5 81 00:04:24,664 --> 00:04:25,865 with a dot. 82 00:04:25,865 --> 00:04:29,736 That dot is the unpaired electron. 83 00:04:29,736 --> 00:04:31,638 And so on, and so on. 84 00:04:31,638 --> 00:04:35,275 And so if you have free radicals and they come along, 85 00:04:35,275 --> 00:04:36,709 and there's some other molecules-- 86 00:04:36,709 --> 00:04:38,711 it's not going to be this one, but maybe there's 87 00:04:38,711 --> 00:04:41,581 something like an antioxidant in those blueberries. 88 00:04:41,581 --> 00:04:43,182 It's going to come along. 89 00:04:43,182 --> 00:04:45,551 I've got electrons I could give you. 90 00:04:45,551 --> 00:04:46,286 Here, have one. 91 00:04:46,286 --> 00:04:47,620 I see how needy you are. 92 00:04:47,620 --> 00:04:49,355 I see how badly you want one. 93 00:04:49,355 --> 00:04:50,423 You can take one of mine. 94 00:04:50,423 --> 00:04:51,724 And I'll be fine. 95 00:04:51,724 --> 00:04:54,560 I'll be fine. 96 00:04:54,560 --> 00:04:57,263 Or maybe we'll form a bond with that. 97 00:04:57,263 --> 00:04:59,532 Those are antioxidants. 98 00:04:59,532 --> 00:05:00,600 But that's not the topic. 99 00:05:00,600 --> 00:05:03,870 The topic is we're making this new material called a polymer. 100 00:05:03,870 --> 00:05:04,871 So how does that work? 101 00:05:04,871 --> 00:05:06,339 Well, to understand that, we've got 102 00:05:06,339 --> 00:05:09,275 to make a radical out of a special case. 103 00:05:09,275 --> 00:05:12,645 We've got to make a radical out of a double-bonded molecule. 104 00:05:12,645 --> 00:05:18,851 So now I'm going from methane to the double-bonded ethane. 105 00:05:18,851 --> 00:05:19,385 Now, hang on. 106 00:05:19,385 --> 00:05:22,722 Let me put this up here. 107 00:05:22,722 --> 00:05:28,361 And in the case of a double bond, something very important 108 00:05:28,361 --> 00:05:29,662 happens. 109 00:05:29,662 --> 00:05:32,265 Something very important happens. 110 00:05:32,265 --> 00:05:35,601 And the reason is that I've got two bonds. 111 00:05:35,601 --> 00:05:37,036 I've got two bonds, not one. 112 00:05:37,036 --> 00:05:38,938 Well, that's what double bond-- 113 00:05:38,938 --> 00:05:41,774 that is what double bond means. 114 00:05:41,774 --> 00:05:44,110 But I can now-- because I've got a double bond, 115 00:05:44,110 --> 00:05:45,912 I can do something very important. 116 00:05:45,912 --> 00:05:47,347 I can do something very important. 117 00:05:47,347 --> 00:05:50,917 When I turn that molecule into a radical, 118 00:05:50,917 --> 00:05:53,119 something special happens. 119 00:05:53,119 --> 00:05:55,688 So what I'm going to do is I'm not going to call it chlorine. 120 00:05:55,688 --> 00:05:57,657 I'm going to just call it R dot. 121 00:05:57,657 --> 00:06:01,060 And because now we're making a polymer, and this is called-- 122 00:06:01,060 --> 00:06:02,328 well, it's got different names. 123 00:06:02,328 --> 00:06:04,664 It's called radical, or sometimes you'll 124 00:06:04,664 --> 00:06:10,002 see it as addition polymerization. 125 00:06:10,002 --> 00:06:15,708 And this is the first kind of polymer I want to talk about. 126 00:06:15,708 --> 00:06:17,176 And so I'm going-- 127 00:06:17,176 --> 00:06:18,811 you saw how it worked with chlorine. 128 00:06:18,811 --> 00:06:21,247 I'm just going to say, I've got something called R. 129 00:06:21,247 --> 00:06:23,850 And it's called a radical initiator. 130 00:06:23,850 --> 00:06:26,953 And I'm going to draw the dot there, just 131 00:06:26,953 --> 00:06:28,621 like I had the dot on chlorine. 132 00:06:28,621 --> 00:06:31,758 This is going to be the radical initiator. 133 00:06:31,758 --> 00:06:35,428 Radical initiator. 134 00:06:35,428 --> 00:06:40,666 And I'm going to now bring this to my double-bonded molecule. 135 00:06:40,666 --> 00:06:41,901 That's the key. 136 00:06:41,901 --> 00:06:43,503 The key is in the double bond. 137 00:06:43,503 --> 00:06:44,704 So watch what happens. 138 00:06:44,704 --> 00:06:46,739 So first, here's what happens. 139 00:06:46,739 --> 00:06:50,409 I've got R with its dot plus-- 140 00:06:50,409 --> 00:06:52,078 and again, I'm going to go Lewis. 141 00:06:52,078 --> 00:06:55,515 I'm going to have all those electrons in the bonds spelled 142 00:06:55,515 --> 00:06:57,216 out for you with dots. 143 00:06:57,216 --> 00:07:02,455 So R plus C. Two pairs of electrons in there. 144 00:07:02,455 --> 00:07:03,122 Do you see that? 145 00:07:03,122 --> 00:07:05,892 There's my double bond. 146 00:07:05,892 --> 00:07:07,093 And here are the hydrogens. 147 00:07:07,093 --> 00:07:08,795 I'm not going to draw them every time. 148 00:07:08,795 --> 00:07:10,897 Those sticks have hydrogens on the ends. 149 00:07:13,666 --> 00:07:14,934 But now watch what happens. 150 00:07:14,934 --> 00:07:19,272 So now, this radical, like the chlorine, 151 00:07:19,272 --> 00:07:24,010 it sees this electron, and it says, aha, I can take you. 152 00:07:24,010 --> 00:07:24,677 I can take you. 153 00:07:27,513 --> 00:07:30,349 And I will be happy if I take this. 154 00:07:30,349 --> 00:07:34,153 And this double-bonded molecule can't really 155 00:07:34,153 --> 00:07:35,555 stop it from happening. 156 00:07:35,555 --> 00:07:40,827 So the radical now can bond to the carbon over here. 157 00:07:40,827 --> 00:07:42,528 It's got these two. 158 00:07:42,528 --> 00:07:45,765 Those are those two hydrogens that were there. 159 00:07:45,765 --> 00:07:46,866 But now watch what happens. 160 00:07:46,866 --> 00:07:51,337 Now I've got here, here, here. 161 00:07:51,337 --> 00:07:53,172 And then I've got this. 162 00:07:53,172 --> 00:07:54,073 And I've got this. 163 00:07:57,443 --> 00:08:00,246 But now this is a radical, because this 164 00:08:00,246 --> 00:08:03,549 has an unpaired electron. 165 00:08:03,549 --> 00:08:06,519 This has an unpaired electron. 166 00:08:06,519 --> 00:08:10,389 And so often what we'll do is we'll write this. 167 00:08:10,389 --> 00:08:11,624 We'll often just write it. 168 00:08:11,624 --> 00:08:14,260 I'm just going to rewrite it, just because then it gets us 169 00:08:14,260 --> 00:08:19,298 in the mood for what's going to happen next as a single bond 170 00:08:19,298 --> 00:08:22,468 with the two hydrogens and the radical sitting there. 171 00:08:22,468 --> 00:08:24,337 I just took this unpaired electron 172 00:08:24,337 --> 00:08:27,740 and put it out on the end there. 173 00:08:27,740 --> 00:08:30,676 That's a radical again. 174 00:08:30,676 --> 00:08:33,846 And I haven't broken the bond. 175 00:08:33,846 --> 00:08:35,681 That's the key. 176 00:08:35,681 --> 00:08:37,783 The double bond allowed a radical 177 00:08:37,783 --> 00:08:41,654 to come in, take an electron, make 178 00:08:41,654 --> 00:08:45,224 a new radical out of the whole thing, and remain stable. 179 00:08:45,224 --> 00:08:47,260 That's what the double bond gave me. 180 00:08:47,260 --> 00:08:51,163 So if I go to step two, what happens? 181 00:08:51,163 --> 00:08:53,966 If I go to step two, well, now, I've 182 00:08:53,966 --> 00:08:56,936 got this R that's sitting here. 183 00:08:56,936 --> 00:08:59,972 And I've got these here. 184 00:08:59,972 --> 00:09:00,873 And I've got-- 185 00:09:00,873 --> 00:09:03,809 I'll put them in explicitly, and there. 186 00:09:03,809 --> 00:09:12,285 Obviously, this is in a bucket of these C2H4 molecules. 187 00:09:12,285 --> 00:09:14,921 They're all over the place. 188 00:09:14,921 --> 00:09:18,257 And now this is going to see-- 189 00:09:18,257 --> 00:09:20,426 so we're going to do that, and this 190 00:09:20,426 --> 00:09:22,028 is going to see another one. 191 00:09:22,028 --> 00:09:23,663 Let's put that one in here. 192 00:09:23,663 --> 00:09:24,597 Here we go. 193 00:09:24,597 --> 00:09:27,700 A double bond, nice and happy, floating along. 194 00:09:27,700 --> 00:09:32,204 And this radical version of it sees it. 195 00:09:32,204 --> 00:09:34,206 And it says, nope, I need that electron. 196 00:09:34,206 --> 00:09:35,841 Thank you very much. 197 00:09:35,841 --> 00:09:39,378 And so you get this. 198 00:09:39,378 --> 00:09:42,582 Single bond, single bond. 199 00:09:42,582 --> 00:09:46,385 And we'll just put it out here. 200 00:09:46,385 --> 00:09:48,621 And so now, how many did I have? 201 00:09:48,621 --> 00:09:52,124 2, 4, and here's another one. 202 00:09:52,124 --> 00:09:53,626 And there it is. 203 00:09:53,626 --> 00:09:56,095 And I've got another radical. 204 00:09:56,095 --> 00:09:59,432 I've got another radical. 205 00:09:59,432 --> 00:10:04,470 The thing stays radical until it finds another R dot. 206 00:10:08,407 --> 00:10:11,477 So this just goes on and on and on. 207 00:10:11,477 --> 00:10:14,347 This is a new radical. 208 00:10:14,347 --> 00:10:17,550 New radical. 209 00:10:17,550 --> 00:10:23,823 And each time it finds a double-bonded C2H4 molecule, 210 00:10:23,823 --> 00:10:27,627 it can take it, add it to the chain, add it to the chain. 211 00:10:27,627 --> 00:10:30,296 Sometimes this is called chain polymerization, 212 00:10:30,296 --> 00:10:33,165 addition polymerization, radical polymerization. 213 00:10:33,165 --> 00:10:34,233 You see it's all the same. 214 00:10:34,233 --> 00:10:37,370 You see how it works, because I'm making a chain, 215 00:10:37,370 --> 00:10:40,272 and I keep on adding the same building 216 00:10:40,272 --> 00:10:42,141 block, the same molecule. 217 00:10:42,141 --> 00:10:44,844 That's really important. 218 00:10:44,844 --> 00:10:51,851 The same molecule, and then et cetera, et cetera. 219 00:10:51,851 --> 00:10:54,754 Well, how long is et cetera? 220 00:10:54,754 --> 00:11:00,993 Well, typical polymers go on for a long time. 221 00:11:00,993 --> 00:11:03,729 We're talking a minimum of 100 times. 222 00:11:03,729 --> 00:11:07,900 100, you might be able to draw that all the way down, 223 00:11:07,900 --> 00:11:09,235 maybe down to there. 224 00:11:09,235 --> 00:11:13,873 But a lot of polymers go to 100,000 or a million chain 225 00:11:13,873 --> 00:11:16,208 links, a million. 226 00:11:16,208 --> 00:11:22,882 That makes this class of materials extremely unique. 227 00:11:22,882 --> 00:11:25,518 And we're going to talk about them in the next-- 228 00:11:25,518 --> 00:11:29,255 over the next-- well, during this week. 229 00:11:29,255 --> 00:11:31,090 What I want to do is give you a couple 230 00:11:31,090 --> 00:11:34,627 of reasons why they're unique, and then we're 231 00:11:34,627 --> 00:11:37,129 going to go into my "Why This Matters." 232 00:11:39,665 --> 00:11:41,567 What we started with was a monomer. 233 00:11:41,567 --> 00:11:45,371 In this case, we started with ethylene or ethene, 234 00:11:45,371 --> 00:11:48,708 and so here was our monomer. 235 00:11:48,708 --> 00:11:51,644 And what we ended up with is a polymer. 236 00:11:54,480 --> 00:11:57,083 And in this case, it's-- 237 00:11:57,083 --> 00:12:02,521 oh, boy-- I'll draw it straight like I did there. 238 00:12:02,521 --> 00:12:03,723 OK, here we go. 239 00:12:03,723 --> 00:12:04,857 Here we go. 240 00:12:04,857 --> 00:12:07,259 This is the polymer. 241 00:12:07,259 --> 00:12:13,899 But see, I don't want to write 100,000 carbon letters 242 00:12:13,899 --> 00:12:15,301 on my page. 243 00:12:15,301 --> 00:12:18,237 You can you can't blame polymer chemists for that. 244 00:12:18,237 --> 00:12:22,274 And so what we do is we have a notation, where 245 00:12:22,274 --> 00:12:26,245 if this was the monomer, one. 246 00:12:26,245 --> 00:12:28,180 Poly, many. 247 00:12:28,180 --> 00:12:32,084 Mer, C2H4. 248 00:12:32,084 --> 00:12:34,520 Then what you do is you take the monomer 249 00:12:34,520 --> 00:12:36,122 and you write it in a special way 250 00:12:36,122 --> 00:12:37,623 to show that it's become a polymer. 251 00:12:37,623 --> 00:12:40,860 And you put the monomer inside. 252 00:12:40,860 --> 00:12:43,696 Oh, let's just write those hydrogens explicitly. 253 00:12:43,696 --> 00:12:44,230 Why not? 254 00:12:46,665 --> 00:12:47,299 There they are. 255 00:12:47,299 --> 00:12:50,536 They were there, too. 256 00:12:50,536 --> 00:12:53,305 But now what you do is you put parentheses. 257 00:12:53,305 --> 00:13:00,913 And to show that it's a polymer, this bond comes out the edge. 258 00:13:00,913 --> 00:13:04,650 That shows I had this monomer. 259 00:13:04,650 --> 00:13:09,188 Now, notice, this is the same as a monomer, but a single bond. 260 00:13:09,188 --> 00:13:09,688 Why? 261 00:13:09,688 --> 00:13:13,659 Because that double bond, to keep on making it radical, 262 00:13:13,659 --> 00:13:15,427 I change them all into single bonds. 263 00:13:15,427 --> 00:13:18,731 Each time I made the chain longer. 264 00:13:18,731 --> 00:13:23,435 And then we put an n, because it could repeat n times. 265 00:13:23,435 --> 00:13:25,404 And that's a polymer. 266 00:13:25,404 --> 00:13:28,541 So the chain bonds are sticking out of the edges 267 00:13:28,541 --> 00:13:31,277 like that of the parentheses. 268 00:13:31,277 --> 00:13:33,312 Polymer chemists aren't as-- 269 00:13:33,312 --> 00:13:35,347 the crystallographers, you don't want to upset. 270 00:13:35,347 --> 00:13:37,449 Polymer chemists are fine. 271 00:13:37,449 --> 00:13:41,987 So if you put brackets there, yeah, they're OK with it. 272 00:13:41,987 --> 00:13:43,355 It's not so bad. 273 00:13:43,355 --> 00:13:45,090 Parentheses, brackets. 274 00:13:45,090 --> 00:13:48,494 The main thing is those bonds that are polymerizing, 275 00:13:48,494 --> 00:13:50,696 those bonds that are forming the chain 276 00:13:50,696 --> 00:13:52,965 have to come out of the parentheses, 277 00:13:52,965 --> 00:13:56,936 and then the little n there is how many times. 278 00:13:56,936 --> 00:13:59,772 So a couple of things we can talk about. 279 00:13:59,772 --> 00:14:04,176 So polymer, monomer. 280 00:14:04,176 --> 00:14:06,345 Well, one thing, a couple of things. 281 00:14:06,345 --> 00:14:10,349 So the molecular weight is going to be high. 282 00:14:10,349 --> 00:14:13,285 It's going to be typically, and again, 283 00:14:13,285 --> 00:14:18,457 thousands of grams per mole, because it's 284 00:14:18,457 --> 00:14:20,492 a mole of the molecule. 285 00:14:20,492 --> 00:14:22,528 This is a molecule. 286 00:14:22,528 --> 00:14:23,329 This is a molecule. 287 00:14:23,329 --> 00:14:28,167 It's just a very, very long chain molecule. 288 00:14:28,167 --> 00:14:30,603 And so polymer people and bio people, 289 00:14:30,603 --> 00:14:34,173 they like using Daltons. 290 00:14:34,173 --> 00:14:42,448 1 Dalton equals 1 gram per mole. 291 00:14:42,448 --> 00:14:44,483 Why switch to Daltons? 292 00:14:44,483 --> 00:14:47,253 I don't know! 293 00:14:47,253 --> 00:14:49,321 It's just a unit thing. 294 00:14:49,321 --> 00:14:50,656 So don't get confused. 295 00:14:50,656 --> 00:14:52,057 Dalton is a gram per mole. 296 00:14:52,057 --> 00:14:57,029 A kiloDalton is 1,000 grams per mole. 297 00:14:57,029 --> 00:15:00,499 We can say like a Da. 298 00:15:00,499 --> 00:15:04,570 Maybe they just like the symbol, Da. 299 00:15:04,570 --> 00:15:06,071 Or kDa for kiloDaltons. 300 00:15:06,071 --> 00:15:08,240 It's just grams per mole, thousands of grams. 301 00:15:08,240 --> 00:15:14,079 But now one long chain, if I know the molecular weight 302 00:15:14,079 --> 00:15:15,681 in grams per mole, then I kind of also 303 00:15:15,681 --> 00:15:18,250 could know how long it is. 304 00:15:18,250 --> 00:15:20,319 Back and forth, it's just a molecule. 305 00:15:20,319 --> 00:15:23,822 It's just that this is a very, very big molecule. 306 00:15:23,822 --> 00:15:27,159 And so sometimes you'll see it called a macromolecule. 307 00:15:27,159 --> 00:15:28,761 Macro. 308 00:15:28,761 --> 00:15:29,428 It's huge! 309 00:15:32,631 --> 00:15:36,535 It's a long chain. 310 00:15:36,535 --> 00:15:43,542 You just think about how the length is on the order of-- 311 00:15:43,542 --> 00:15:44,710 I'll spell it out-- microns. 312 00:15:47,746 --> 00:15:48,814 Just think about it. 313 00:15:48,814 --> 00:15:50,382 We've been talking about a lot of different materials 314 00:15:50,382 --> 00:15:51,050 in this class. 315 00:15:51,050 --> 00:15:55,587 We've been talking about a lot of different solid materials. 316 00:15:55,587 --> 00:15:56,622 Perfect crystals. 317 00:15:56,622 --> 00:15:58,324 Crystals with defects. 318 00:15:58,324 --> 00:16:00,259 Amorphous materials. 319 00:16:00,259 --> 00:16:02,227 Molecular solids. 320 00:16:02,227 --> 00:16:05,164 This is another class of solid, but you can really 321 00:16:05,164 --> 00:16:07,066 start to think about why this is so different. 322 00:16:07,066 --> 00:16:13,172 Because if this thing is 100,000 or a million units long, 323 00:16:13,172 --> 00:16:18,110 that strand is a very long piece of spaghetti. 324 00:16:18,110 --> 00:16:20,479 And that means that different things can happen. 325 00:16:20,479 --> 00:16:24,850 And that's one of the reasons why polymers are so interesting 326 00:16:24,850 --> 00:16:27,586 and can be so useful. 327 00:16:27,586 --> 00:16:30,289 And so if you think about taking it longer, this isn't even-- 328 00:16:30,289 --> 00:16:32,057 we're not even close to how long-- 329 00:16:32,057 --> 00:16:34,626 this is still just a little longer, but what I'm showing 330 00:16:34,626 --> 00:16:35,761 you is something important. 331 00:16:35,761 --> 00:16:38,330 If I've got spaghetti that that's long, 332 00:16:38,330 --> 00:16:41,200 you better believe it can tangle up. 333 00:16:41,200 --> 00:16:43,202 And so when you think about one of these strands 334 00:16:43,202 --> 00:16:44,603 or maybe a couple of them, they're 335 00:16:44,603 --> 00:16:47,639 going to usually, often, not always-- 336 00:16:47,639 --> 00:16:50,576 you can make crystals out of polymers, but a lot of times 337 00:16:50,576 --> 00:16:55,347 they're going to tangle, because they're just so long. 338 00:16:55,347 --> 00:16:58,317 And the degree of the length, by the way, that's 339 00:16:58,317 --> 00:17:04,323 another thing, degree of polymerization. 340 00:17:04,323 --> 00:17:06,492 Ah, why was my O so big there? 341 00:17:06,492 --> 00:17:08,660 I don't know. 342 00:17:08,660 --> 00:17:10,429 It was a moment. 343 00:17:10,429 --> 00:17:16,335 I'm feeling it with the O. And that's the number of mer-- 344 00:17:16,335 --> 00:17:18,203 yeah, it's a polymer-- 345 00:17:18,203 --> 00:17:21,006 mer units. 346 00:17:21,006 --> 00:17:24,009 And that's per polymer. 347 00:17:24,009 --> 00:17:36,255 And this is average, because as you can imagine, it's very-- 348 00:17:36,255 --> 00:17:38,123 I'm going out to a million. 349 00:17:38,123 --> 00:17:42,761 Did I hit a million or did I get 990,000? 350 00:17:42,761 --> 00:17:46,799 Or did I get a million and 10? 351 00:17:46,799 --> 00:17:49,935 You don't control the length exactly. 352 00:17:49,935 --> 00:17:52,538 And so the degree of polymerization 353 00:17:52,538 --> 00:17:55,340 is the number that is the average. 354 00:17:55,340 --> 00:17:56,308 It's the average. 355 00:17:56,308 --> 00:17:58,444 It's the same as the molecular weight. 356 00:17:58,444 --> 00:18:01,280 It's an average, because the strands have a distribution. 357 00:18:01,280 --> 00:18:05,184 And we'll talk about that more on Wednesday. 358 00:18:05,184 --> 00:18:09,021 But now I just want to get down some polymer insights. 359 00:18:11,657 --> 00:18:13,292 So we got things like molecular weight, 360 00:18:13,292 --> 00:18:17,129 degree of polymerization. 361 00:18:17,129 --> 00:18:19,965 Now, these are very long. 362 00:18:19,965 --> 00:18:23,335 And so you can imagine that it's kind of like glasses 363 00:18:23,335 --> 00:18:24,269 when we did glasses. 364 00:18:24,269 --> 00:18:25,771 These are really long chains. 365 00:18:25,771 --> 00:18:29,174 You can imagine as a liquid that might be pretty viscous. 366 00:18:29,174 --> 00:18:31,343 That might be pretty viscous. 367 00:18:31,343 --> 00:18:33,445 You could also imagine that when you solidify it, 368 00:18:33,445 --> 00:18:36,949 it might be pretty disordered, or maybe crystalline. 369 00:18:36,949 --> 00:18:38,717 It might have some similarities with glass. 370 00:18:38,717 --> 00:18:40,652 Again, we'll talk about that more Wednesday. 371 00:18:40,652 --> 00:18:43,088 But the one thing I want to highlight now 372 00:18:43,088 --> 00:18:47,159 is that what can happen because it's so long 373 00:18:47,159 --> 00:18:49,695 is that you can literally get what? 374 00:18:49,695 --> 00:18:54,466 You can literally get like one polymer chain that 375 00:18:54,466 --> 00:18:58,403 finds itself wanting to form a crystal literally 376 00:18:58,403 --> 00:19:00,706 like in the middle of itself. 377 00:19:00,706 --> 00:19:03,609 And then it's like, OK, I can stack and form a nice crystal, 378 00:19:03,609 --> 00:19:05,344 but now I can't again. 379 00:19:05,344 --> 00:19:10,382 And now, oh, look, I think I can pack in nicely as a crystal. 380 00:19:10,382 --> 00:19:12,417 And now I can't again. 381 00:19:12,417 --> 00:19:14,520 And it just goes, I could-- 382 00:19:14,520 --> 00:19:16,622 I'm really enjoying this. 383 00:19:16,622 --> 00:19:18,190 I could just keep going. 384 00:19:18,190 --> 00:19:21,326 That's one polymer strand! 385 00:19:21,326 --> 00:19:22,761 And it would keep going. 386 00:19:22,761 --> 00:19:27,499 It literally would, because it's like 100,000 units long. 387 00:19:27,499 --> 00:19:30,235 So you can imagine that polymers, just one 388 00:19:30,235 --> 00:19:33,772 strand of a polymer can be incredibly complicated, 389 00:19:33,772 --> 00:19:37,442 because it might have some regions that are crystalline 390 00:19:37,442 --> 00:19:38,610 and some that are amorphous. 391 00:19:38,610 --> 00:19:42,114 And by the way, we know that the crystalline region 392 00:19:42,114 --> 00:19:43,882 will be very different. 393 00:19:43,882 --> 00:19:46,418 This is going to have the lowest volume per mole. 394 00:19:46,418 --> 00:19:48,554 So this will have-- maybe this will be the hardest. 395 00:19:48,554 --> 00:19:51,590 Maybe it will be the most brittle. 396 00:19:51,590 --> 00:19:53,392 So does it crystallize? 397 00:19:53,392 --> 00:19:54,293 Does it not? 398 00:19:54,293 --> 00:19:57,729 That's going to be something that's very important. 399 00:19:57,729 --> 00:20:00,632 How much of it crystallizes? 400 00:20:00,632 --> 00:20:03,602 A micron, by the way, the length is also important. 401 00:20:03,602 --> 00:20:06,538 That's like visible light, wavelength. 402 00:20:06,538 --> 00:20:10,542 So optical properties will depend on these things. 403 00:20:10,542 --> 00:20:16,048 And so what you have is this new form of matter 404 00:20:16,048 --> 00:20:18,917 that we have in the last 50 years 405 00:20:18,917 --> 00:20:22,688 engineered and understood more and more how to control. 406 00:20:22,688 --> 00:20:28,994 And so we're talking about this addition polymerization. 407 00:20:28,994 --> 00:20:34,666 This list goes on and on and on now today. 408 00:20:34,666 --> 00:20:36,134 So what is this list? 409 00:20:36,134 --> 00:20:37,569 Well, these are all-- 410 00:20:37,569 --> 00:20:39,204 I want you to notice here-- 411 00:20:39,204 --> 00:20:41,073 monomer. 412 00:20:41,073 --> 00:20:42,874 This is the polymer name. 413 00:20:42,874 --> 00:20:44,610 This is the monomer. 414 00:20:44,610 --> 00:20:45,444 Here's the polymer. 415 00:20:45,444 --> 00:20:46,845 They should have put parentheses there. 416 00:20:46,845 --> 00:20:48,347 We'll excuse that, because you can 417 00:20:48,347 --> 00:20:51,383 feel that those are going outside of the parentheses 418 00:20:51,383 --> 00:20:53,485 or brackets. 419 00:20:53,485 --> 00:20:55,087 And then here's the use. 420 00:20:55,087 --> 00:20:56,221 So what did we just do? 421 00:20:56,221 --> 00:20:58,023 We just did polyethylene. 422 00:20:58,023 --> 00:20:59,858 Polyethylene is right there. 423 00:20:59,858 --> 00:21:01,693 That's the polymer polyethylene. 424 00:21:01,693 --> 00:21:03,795 There is the monomer. 425 00:21:03,795 --> 00:21:04,896 There is the polymer. 426 00:21:04,896 --> 00:21:06,732 Now, notice something about every single one 427 00:21:06,732 --> 00:21:08,200 of these monomers. 428 00:21:08,200 --> 00:21:08,867 There it is. 429 00:21:08,867 --> 00:21:10,435 They've all got that double bond, 430 00:21:10,435 --> 00:21:12,904 that double-bonded carbon. 431 00:21:12,904 --> 00:21:15,641 So when I put a radical initiator 432 00:21:15,641 --> 00:21:22,514 in a soup of those monomers, I can form polymer chains. 433 00:21:22,514 --> 00:21:23,982 I can form polymer chains. 434 00:21:23,982 --> 00:21:25,817 And those are the polymers you make. 435 00:21:25,817 --> 00:21:27,419 And notice they all start-- 436 00:21:27,419 --> 00:21:29,521 these are the same unit repeating 437 00:21:29,521 --> 00:21:31,189 over and over and over again. 438 00:21:31,189 --> 00:21:35,093 And notice the flexibility here. 439 00:21:35,093 --> 00:21:38,096 So in polyethylene, which is one of the simplest cases 440 00:21:38,096 --> 00:21:41,967 and is the most common polymer, these are just a few uses. 441 00:21:41,967 --> 00:21:45,070 If I just take one of those hydrogens off 442 00:21:45,070 --> 00:21:47,939 of one of the two carbons-- 443 00:21:47,939 --> 00:21:50,108 there's polyethylene up there-- 444 00:21:50,108 --> 00:21:52,711 if I just take one of the hydrogens off, 445 00:21:52,711 --> 00:21:58,183 and instead I put a benzene ring. 446 00:21:58,183 --> 00:22:00,652 So now I've got this. 447 00:22:03,188 --> 00:22:03,922 Oh, boy. 448 00:22:03,922 --> 00:22:05,090 Did I draw that? 449 00:22:05,090 --> 00:22:05,957 Yeah, it's OK. 450 00:22:05,957 --> 00:22:08,460 Here's my hydrogens coming off of the benzene. 451 00:22:08,460 --> 00:22:09,728 There you go. 452 00:22:09,728 --> 00:22:10,929 There you go. 453 00:22:10,929 --> 00:22:15,467 And there, and there, and oh, good. 454 00:22:15,467 --> 00:22:19,838 I've drawn polystyrene, haven't I? 455 00:22:19,838 --> 00:22:23,241 No, I have not! 456 00:22:23,241 --> 00:22:24,676 Because you've got to come out! 457 00:22:27,779 --> 00:22:29,715 That's a polymer. 458 00:22:29,715 --> 00:22:30,982 Now it's a polymer. 459 00:22:30,982 --> 00:22:31,783 I came out. 460 00:22:35,954 --> 00:22:37,155 Well, that's pretty simple. 461 00:22:37,155 --> 00:22:40,659 All I did is I just took the polyethylene, 462 00:22:40,659 --> 00:22:42,361 and I put a benzene ring there. 463 00:22:42,361 --> 00:22:45,130 And I get Styrofoam if I put air through it 464 00:22:45,130 --> 00:22:47,065 as I make it processing. 465 00:22:47,065 --> 00:22:49,634 Or I can make all sorts of other things out of it. 466 00:22:49,634 --> 00:22:51,770 That's polystyrene. 467 00:22:51,770 --> 00:22:55,173 That's polystyrene. 468 00:22:55,173 --> 00:23:00,946 This is why polymers have become such an incredibly 469 00:23:00,946 --> 00:23:05,150 important and enormous part of our lives, 470 00:23:05,150 --> 00:23:08,920 because you can see if I just change the monomer, I just 471 00:23:08,920 --> 00:23:11,189 change one thing in one molecule, 472 00:23:11,189 --> 00:23:13,492 and then get a bucket of those. 473 00:23:13,492 --> 00:23:18,430 I might completely change the solid that comes out of it. 474 00:23:18,430 --> 00:23:20,265 But all sorts of things are going to change. 475 00:23:20,265 --> 00:23:22,667 You can imagine that just the way the chain folds up 476 00:23:22,667 --> 00:23:25,203 on itself like that, maybe the way the chain 477 00:23:25,203 --> 00:23:28,473 comes and talks to another chain, or maybe 478 00:23:28,473 --> 00:23:29,975 a part of itself. 479 00:23:29,975 --> 00:23:34,546 When I say talk and I'm talking about chemistry, I mean bond. 480 00:23:34,546 --> 00:23:36,581 Is it Van der Waals? 481 00:23:36,581 --> 00:23:40,018 The surface area is enormous here. 482 00:23:40,018 --> 00:23:41,653 The surface area of one mol-- 483 00:23:41,653 --> 00:23:42,487 we did this, right? 484 00:23:42,487 --> 00:23:43,655 We looked at boiling points. 485 00:23:43,655 --> 00:23:48,326 As you get a little longer, a little longer, to C12. 486 00:23:48,326 --> 00:23:51,630 This is C hundreds of thousands. 487 00:23:51,630 --> 00:23:57,536 So the amount of bonding, London dispersion, is enormous. 488 00:23:57,536 --> 00:23:59,671 That's one of the reasons these can be very strong. 489 00:23:59,671 --> 00:24:01,440 But the tunability is also enormous, 490 00:24:01,440 --> 00:24:03,942 because I can just swap in a different group 491 00:24:03,942 --> 00:24:05,744 here, and polymerize that. 492 00:24:09,815 --> 00:24:12,684 This is why this was so exciting when it was-- 493 00:24:12,684 --> 00:24:16,288 polymers were first made really in the '40s and '50s. 494 00:24:16,288 --> 00:24:21,126 They really started coming into the market in the '70s 495 00:24:21,126 --> 00:24:22,294 en masse. 496 00:24:22,294 --> 00:24:27,632 And now I want to tell you why this matters. 497 00:24:27,632 --> 00:24:30,268 We're going to start with a commercial. 498 00:24:30,268 --> 00:24:38,310 This is an ad on television by Pepsi in 1978. 499 00:24:38,310 --> 00:24:39,978 And I thought this would be a nice way 500 00:24:39,978 --> 00:24:41,646 to start my "Why This Matters." 501 00:24:41,646 --> 00:24:43,882 It's only 30 seconds. 502 00:24:43,882 --> 00:24:44,382 Uh-oh. 503 00:24:47,819 --> 00:24:48,820 [VIDEO PLAYBACK] 504 00:24:48,820 --> 00:24:51,456 Pepsi Cola's new 2 liter plastic bottle. 505 00:24:56,428 --> 00:24:57,429 It's tough. 506 00:25:03,435 --> 00:25:04,936 Really tough. 507 00:25:09,808 --> 00:25:13,111 And besides being touch, Pepsi Cola's new 2 liter 508 00:25:13,111 --> 00:25:16,414 plastic bottle is 25% lighter than glass. 509 00:25:16,414 --> 00:25:17,682 It's tough and light. 510 00:25:17,682 --> 00:25:18,250 [END PLAYBACK] 511 00:25:18,250 --> 00:25:19,017 Tough and light. 512 00:25:19,017 --> 00:25:22,821 Now, apart from some other potential differences 513 00:25:22,821 --> 00:25:26,558 you may have noticed with today's times, that 514 00:25:26,558 --> 00:25:27,225 was the key. 515 00:25:27,225 --> 00:25:29,661 That was one of the keys. 516 00:25:29,661 --> 00:25:31,396 So they could make-- 517 00:25:31,396 --> 00:25:34,199 Pepsi and Coke, Coca-Cola, could make 518 00:25:34,199 --> 00:25:38,169 bottles that were lighter than glass, but not break. 519 00:25:38,169 --> 00:25:39,971 That was a very big deal. 520 00:25:39,971 --> 00:25:42,674 That was a very big deal. 521 00:25:42,674 --> 00:25:44,776 And they really started-- 522 00:25:44,776 --> 00:25:48,079 in a lot of ways, they started the revolution 523 00:25:48,079 --> 00:25:52,517 of plastics and polymers in commercial products. 524 00:25:56,221 --> 00:25:59,658 Now, if you fast forward to today, 525 00:25:59,658 --> 00:26:01,560 I just want to show you how bottles are made. 526 00:26:01,560 --> 00:26:02,894 That's a 2 liter bottle. 527 00:26:02,894 --> 00:26:05,463 Here is a 2 liter bottle making plant. 528 00:26:05,463 --> 00:26:07,799 And I think it's always interesting to see how what 529 00:26:07,799 --> 00:26:09,334 you're buying is actually made. 530 00:26:09,334 --> 00:26:11,236 So here's just a little short video. 531 00:26:11,236 --> 00:26:11,903 [VIDEO PLAYBACK] 532 00:26:11,903 --> 00:26:14,973 Harden almost instantly thanks to a built-in cooling system. 533 00:26:17,609 --> 00:26:19,644 These preforms are now on their way 534 00:26:19,644 --> 00:26:21,646 to becoming single-serving juice bottles. 535 00:26:27,052 --> 00:26:30,188 This is another plastic injection molding machine. 536 00:26:30,188 --> 00:26:32,657 It uses the same method to make preforms 537 00:26:32,657 --> 00:26:35,594 for a different model, 1 and 1/2 to 2 liter bottles. 538 00:26:47,205 --> 00:26:50,842 The preform's next stop is a machine called a reheat stretch 539 00:26:50,842 --> 00:26:51,343 blow molder. 540 00:26:53,945 --> 00:26:57,882 In a matter of seconds, it heats each preform just enough 541 00:26:57,882 --> 00:27:01,486 to make the plastic malleable, then inserts a rod 542 00:27:01,486 --> 00:27:04,155 to stretch the preform lengthwise, 543 00:27:04,155 --> 00:27:07,392 while at the same time blowing in air at extremely 544 00:27:07,392 --> 00:27:09,361 high pressure. 545 00:27:09,361 --> 00:27:13,031 This forces the preform into a bottle-shaped mold. 546 00:27:13,031 --> 00:27:15,667 Cold water circulates within the mold to cool. 547 00:27:15,667 --> 00:27:16,635 [END PLAYBACK] 548 00:27:16,635 --> 00:27:18,069 So the reason I wanted to show you 549 00:27:18,069 --> 00:27:23,008 this is it just gives you a sense of the pace, the pace. 550 00:27:23,008 --> 00:27:27,412 Now, the pace is connected to the material and the chemistry. 551 00:27:27,412 --> 00:27:31,282 And it's things that you already know. 552 00:27:31,282 --> 00:27:33,885 When we did stress strain curves, 553 00:27:33,885 --> 00:27:38,056 one of the whole regions of it is called plastic deformation. 554 00:27:38,056 --> 00:27:40,892 These are plastics. 555 00:27:40,892 --> 00:27:42,961 So one of the big advantages of these things 556 00:27:42,961 --> 00:27:46,031 is you can make like a small mold like you do first, 557 00:27:46,031 --> 00:27:49,634 and then that can be doled out to different processes. 558 00:27:49,634 --> 00:27:53,304 And in a matter of less than a second with a little heat, 559 00:27:53,304 --> 00:27:56,374 a little pressure, it can be made into any bottle you want, 560 00:27:56,374 --> 00:27:58,043 and then the next one, and the next one. 561 00:28:00,879 --> 00:28:02,981 Well, let's see. 562 00:28:02,981 --> 00:28:06,117 We buy-- I'm going to write a couple of things here-- 563 00:28:06,117 --> 00:28:06,618 let's see. 564 00:28:06,618 --> 00:28:14,659 We buy as humans 1 million of those bottles, 565 00:28:14,659 --> 00:28:15,360 plastic bottles-- 566 00:28:19,664 --> 00:28:21,032 anybody want to give me a unit? 567 00:28:21,032 --> 00:28:22,400 Day. 568 00:28:22,400 --> 00:28:24,202 It's per minute. 569 00:28:24,202 --> 00:28:26,371 [GASPING] 570 00:28:26,371 --> 00:28:28,106 We buy a million globally per minute. 571 00:28:30,108 --> 00:28:32,544 And the thing is, if you're talking about plastic bottles, 572 00:28:32,544 --> 00:28:35,346 91% of them are not recycled. 573 00:28:35,346 --> 00:28:38,683 91% of them are not recycled. 574 00:28:38,683 --> 00:28:42,721 And so my "Why This Matters," it's 575 00:28:42,721 --> 00:28:44,322 going to turn a little dark right now, 576 00:28:44,322 --> 00:28:52,297 because the thing is, if you compare with what nature does, 577 00:28:52,297 --> 00:28:53,531 these are nature's polymers. 578 00:28:53,531 --> 00:28:56,835 And I will talk about them on Friday a little bit more. 579 00:28:56,835 --> 00:28:58,670 And you can say, well, nature's had millions 580 00:28:58,670 --> 00:29:00,004 of years to work on this, sure. 581 00:29:00,004 --> 00:29:04,676 Nature is the world's greatest polymer engineer. 582 00:29:04,676 --> 00:29:06,678 We are all polymers. 583 00:29:06,678 --> 00:29:10,281 We are all polymers of different types. 584 00:29:10,281 --> 00:29:15,553 Amino acids, sugars, cellulose, keratin. 585 00:29:15,553 --> 00:29:18,223 Nature does this in so many ways. 586 00:29:18,223 --> 00:29:23,128 And of course, by definition, these are biodegradable. 587 00:29:23,128 --> 00:29:24,362 Now, that's what nature makes. 588 00:29:24,362 --> 00:29:27,365 Here's what we make. 589 00:29:27,365 --> 00:29:30,001 Now, this is a beach. 590 00:29:30,001 --> 00:29:30,869 That's a coastline. 591 00:29:30,869 --> 00:29:33,204 And there's a lot of places where you can get some data. 592 00:29:33,204 --> 00:29:34,939 I like Our World in Data. 593 00:29:34,939 --> 00:29:37,709 You guys can take a look at that and many other resources. 594 00:29:37,709 --> 00:29:38,376 Here's a beach. 595 00:29:38,376 --> 00:29:39,644 Here is a guy. 596 00:29:39,644 --> 00:29:41,813 It's hard to see, but he's actually in a boat. 597 00:29:41,813 --> 00:29:43,581 That's a boat. 598 00:29:43,581 --> 00:29:46,451 So that's all water. 599 00:29:46,451 --> 00:29:51,656 And of course, there's a lot of information 600 00:29:51,656 --> 00:29:55,860 lately on things like how much of this stuff 601 00:29:55,860 --> 00:29:57,829 animals are eating. 602 00:29:57,829 --> 00:30:00,431 And there's also a lot of pictures 603 00:30:00,431 --> 00:30:01,900 that are sometimes difficult to see, 604 00:30:01,900 --> 00:30:05,537 where animals get stuck in a piece of plastic, for example. 605 00:30:05,537 --> 00:30:09,340 And that can lead to death, or deformity, as in this case. 606 00:30:09,340 --> 00:30:16,648 And the thing is that we have to think very carefully 607 00:30:16,648 --> 00:30:17,949 about what we're doing. 608 00:30:17,949 --> 00:30:21,019 And we have not done that with regard to polymers. 609 00:30:21,019 --> 00:30:23,288 We have not done that at all. 610 00:30:26,291 --> 00:30:29,460 And just to give you a couple more numbers, here's a chart. 611 00:30:29,460 --> 00:30:34,532 This is how polymers are used today. 612 00:30:34,532 --> 00:30:36,367 Packaging is 40%. 613 00:30:36,367 --> 00:30:40,405 40% of plastic produced today is in packaging. 614 00:30:40,405 --> 00:30:41,739 And the thing is-- 615 00:30:41,739 --> 00:30:42,240 sorry. 616 00:30:42,240 --> 00:30:46,044 40% of the plastics are used only once, 617 00:30:46,044 --> 00:30:47,011 and then thrown away. 618 00:30:47,011 --> 00:30:48,012 We all know that. 619 00:30:48,012 --> 00:30:53,785 We drink a bottle of water out of plastic, or all the way back 620 00:30:53,785 --> 00:30:58,156 to the '70s, the Pepsi and the Coke, and we throw it away. 621 00:31:00,758 --> 00:31:02,994 But the thing is that most of that, 622 00:31:02,994 --> 00:31:05,930 a lot of that, most of that winds up in the oceans. 623 00:31:05,930 --> 00:31:09,200 And it takes about a half a thousand years, 500 years, 624 00:31:09,200 --> 00:31:11,102 to decompose. 625 00:31:11,102 --> 00:31:13,571 So let's see. 626 00:31:13,571 --> 00:31:15,106 A couple more numbers. 627 00:31:15,106 --> 00:31:22,881 So first of all, only 7% of all plastic is recycled. 628 00:31:28,086 --> 00:31:32,357 Now, Coca-Cola and Pepsi could use 629 00:31:32,357 --> 00:31:34,292 a lot more recycled plastic. 630 00:31:34,292 --> 00:31:36,527 One of the main reasons they don't is the containers 631 00:31:36,527 --> 00:31:37,795 wouldn't be see through. 632 00:31:37,795 --> 00:31:39,030 And we can't have that, right? 633 00:31:39,030 --> 00:31:41,733 As consumers, we've got to see it. 634 00:31:41,733 --> 00:31:46,371 It's got to be this beautiful, clear container. 635 00:31:46,371 --> 00:31:49,674 But as I said, most of what's not recycled winds up 636 00:31:49,674 --> 00:31:51,042 in the oceans. 637 00:31:51,042 --> 00:31:56,114 And let's see, in 2050-- 638 00:31:56,114 --> 00:31:57,415 here's one. 639 00:31:57,415 --> 00:32:04,889 In 2050, the plastic in the ocean 640 00:32:04,889 --> 00:32:11,596 will equal the weight of all fish. 641 00:32:16,801 --> 00:32:22,073 That includes whales and large sea animals, everyone. 642 00:32:22,073 --> 00:32:25,209 Now, the thing is that-- 643 00:32:25,209 --> 00:32:26,110 let's see. 644 00:32:26,110 --> 00:32:28,780 Many of these plastics, like polystyrene, there 645 00:32:28,780 --> 00:32:32,283 is an example, they decompose. 646 00:32:32,283 --> 00:32:35,887 And so when they're large, large, 647 00:32:35,887 --> 00:32:37,789 there is a chance to collect them. 648 00:32:37,789 --> 00:32:41,326 But the sunlight out in the ocean, they float up to the top 649 00:32:41,326 --> 00:32:43,428 or they get currents that mix them, 650 00:32:43,428 --> 00:32:47,632 and the sunlight, the UV energy from the sun, decomposes them. 651 00:32:47,632 --> 00:32:50,568 Eventually they get smaller and smaller and smaller. 652 00:32:50,568 --> 00:32:53,004 And eventually, they get really tiny. 653 00:32:53,004 --> 00:32:54,305 Those are called microplastics. 654 00:32:54,305 --> 00:32:55,606 You say, well, why is that bad? 655 00:32:55,606 --> 00:32:58,242 Because it's toxic, for one thing. 656 00:32:58,242 --> 00:33:01,179 Polystyrene is toxic. 657 00:33:01,179 --> 00:33:03,948 The styrene molecule is toxic. 658 00:33:03,948 --> 00:33:07,618 It's a carcinogen. It's a carcinogen. 659 00:33:07,618 --> 00:33:10,321 People who eat seafood in some studies 660 00:33:10,321 --> 00:33:14,192 are estimated to be eating 11,000 pieces of microplastic 661 00:33:14,192 --> 00:33:15,727 a year. 662 00:33:15,727 --> 00:33:19,330 That's what they're ingesting today. 663 00:33:19,330 --> 00:33:22,567 So this is the problem. 664 00:33:22,567 --> 00:33:26,838 We're making these single-use products, single-use, put it 665 00:33:26,838 --> 00:33:31,709 in recycling because I'm a good citizen, but 9 out of 10 times 666 00:33:31,709 --> 00:33:34,278 it doesn't matter, because it's not getting recycled. 667 00:33:34,278 --> 00:33:35,680 Oh, and then it goes in the ocean 668 00:33:35,680 --> 00:33:37,749 where it stays for 500 years. 669 00:33:37,749 --> 00:33:39,650 There's a plastic bottle. 670 00:33:39,650 --> 00:33:42,120 There's fishing lines. 671 00:33:42,120 --> 00:33:43,721 So this is the problem. 672 00:33:43,721 --> 00:33:48,826 We should not be using things on the minute timescale that 673 00:33:48,826 --> 00:33:52,030 then take a half thousand years to decompose 674 00:33:52,030 --> 00:33:55,500 and are extremely toxic when they do. 675 00:33:55,500 --> 00:33:58,603 This is clearly a problem. 676 00:33:58,603 --> 00:34:02,607 Now, there are a lot of people working on this 677 00:34:02,607 --> 00:34:04,208 and thinking about this. 678 00:34:04,208 --> 00:34:04,942 Not enough. 679 00:34:04,942 --> 00:34:07,111 And I want to tell you about a book 680 00:34:07,111 --> 00:34:10,581 that I read when it came out a long time ago. 681 00:34:10,581 --> 00:34:11,549 It's a wonderful book. 682 00:34:11,549 --> 00:34:16,587 And I got reintroduced to it last week. 683 00:34:16,587 --> 00:34:18,556 By David McKay, who unfortunately passed away 684 00:34:18,556 --> 00:34:21,192 recently, but he wrote this book called Sustainable Energy 685 00:34:21,192 --> 00:34:23,161 Without the Hot Air. 686 00:34:23,161 --> 00:34:27,231 And I highly recommend you read this if you haven't. 687 00:34:27,231 --> 00:34:27,799 It's free. 688 00:34:27,799 --> 00:34:28,866 It's a free download. 689 00:34:28,866 --> 00:34:30,368 WithoutHotAir.com. 690 00:34:30,368 --> 00:34:35,440 Because he just goes through sort of simply the math. 691 00:34:35,440 --> 00:34:37,608 And the reason I'm bringing this to your attention-- 692 00:34:37,608 --> 00:34:39,177 he doesn't really talk about plastics. 693 00:34:39,177 --> 00:34:40,244 He talks about energy-- 694 00:34:40,244 --> 00:34:43,514 is I love this discussion in chapter 19. 695 00:34:43,514 --> 00:34:47,685 Chapter 19 is titled "Every BIG helps." 696 00:34:47,685 --> 00:34:49,954 He says, if everyone does a little, 697 00:34:49,954 --> 00:34:53,224 we'll achieve only a little. 698 00:34:53,224 --> 00:34:54,058 That is true. 699 00:34:54,058 --> 00:34:58,629 We have this way of talking about these crises 700 00:34:58,629 --> 00:35:00,631 in little bits, because it makes us feel better, 701 00:35:00,631 --> 00:35:03,000 and it makes companies feel better. 702 00:35:03,000 --> 00:35:05,303 You talk about this with the plastics in straws 703 00:35:05,303 --> 00:35:08,439 has gotten a lot of press. 704 00:35:08,439 --> 00:35:12,343 And companies kind of do their part. 705 00:35:12,343 --> 00:35:13,878 Although, Starbucks is kind of funny, 706 00:35:13,878 --> 00:35:18,182 because they replaced all plastic straws with paper 707 00:35:18,182 --> 00:35:20,585 straws encased in plastic. 708 00:35:20,585 --> 00:35:24,622 That's actually more than the plastic straws to begin with. 709 00:35:24,622 --> 00:35:26,924 Single-use plastic again. 710 00:35:26,924 --> 00:35:28,059 But anyway, they're trying. 711 00:35:28,059 --> 00:35:28,693 They walk away. 712 00:35:28,693 --> 00:35:29,827 They say, we tried. 713 00:35:29,827 --> 00:35:31,762 No! 714 00:35:31,762 --> 00:35:33,998 Because that's doing a little. 715 00:35:33,998 --> 00:35:39,704 The plastic in the ocean is 0.03% from straws. 716 00:35:39,704 --> 00:35:42,106 There's so much more we have to do. 717 00:35:42,106 --> 00:35:44,675 We can't think little about problems like this. 718 00:35:44,675 --> 00:35:47,678 We can't. 719 00:35:47,678 --> 00:35:49,981 We can't do that. 720 00:35:49,981 --> 00:35:51,682 Now, there are some big projects. 721 00:35:51,682 --> 00:35:54,752 This is one that's gotten some attention. 722 00:35:54,752 --> 00:35:56,387 This is called Ocean Cleanup. 723 00:35:56,387 --> 00:35:58,022 Now, they've gotten a lot of attention. 724 00:35:58,022 --> 00:36:01,359 They've got these rigs out there that could collect some 725 00:36:01,359 --> 00:36:04,262 of this plastic in the ocean. 726 00:36:04,262 --> 00:36:07,031 And it's at least thinking big. 727 00:36:07,031 --> 00:36:09,400 There's a lot of bold claims that they're making. 728 00:36:09,400 --> 00:36:12,703 A lot of bold claims, a lot of hype. 729 00:36:12,703 --> 00:36:15,740 But at least it's an attempt to do something big. 730 00:36:15,740 --> 00:36:17,408 One of the limitations here though 731 00:36:17,408 --> 00:36:22,446 is this technology can't go below a centimeter. 732 00:36:22,446 --> 00:36:23,414 It can't go below that. 733 00:36:23,414 --> 00:36:26,284 It's not going to collect below a centimeter. 734 00:36:26,284 --> 00:36:28,219 But there are some studies that estimate 735 00:36:28,219 --> 00:36:30,154 that 90% of the plastic in the ocean 736 00:36:30,154 --> 00:36:33,558 already is below a centimeter, and 60%, 737 00:36:33,558 --> 00:36:37,929 70% of that has already sunk. 738 00:36:37,929 --> 00:36:41,098 Talk about the need to think about this in a big way. 739 00:36:41,098 --> 00:36:44,168 This is a very big problem. 740 00:36:44,168 --> 00:36:46,504 And I hope that more and more people 741 00:36:46,504 --> 00:36:48,873 get excited about trying to tackle it 742 00:36:48,873 --> 00:36:52,310 in big ways, not little ways. 743 00:36:52,310 --> 00:36:56,280 That was my "Why This Matters," nice and happy. 744 00:36:56,280 --> 00:36:57,882 Nice and happy, why? 745 00:36:57,882 --> 00:37:00,885 Because we're going to solve these problems. 746 00:37:00,885 --> 00:37:01,385 That's why. 747 00:37:01,385 --> 00:37:02,220 We have to. 748 00:37:02,220 --> 00:37:05,056 We have no choice. 749 00:37:05,056 --> 00:37:07,058 I mentioned there were two ways to make plastics 750 00:37:07,058 --> 00:37:08,192 that I want to talk about. 751 00:37:08,192 --> 00:37:09,994 I want to talk about the second way now. 752 00:37:14,198 --> 00:37:18,002 So the first way is called radical polymerization, 753 00:37:18,002 --> 00:37:21,872 because I take one mer, and then I make it 754 00:37:21,872 --> 00:37:24,041 into a really long chain. 755 00:37:24,041 --> 00:37:29,080 The second way-- and that right there is nylon, by the way. 756 00:37:29,080 --> 00:37:31,582 Nylon can't be made that way. 757 00:37:31,582 --> 00:37:33,417 Nylon can't be made that way. 758 00:37:33,417 --> 00:37:34,819 And here's the reason. 759 00:37:34,819 --> 00:37:38,356 Because in the second way of making polymers, 760 00:37:38,356 --> 00:37:41,158 we take two different types of mers. 761 00:37:41,158 --> 00:37:48,699 And this way is called condensation polymerization. 762 00:37:59,310 --> 00:38:03,848 It's a different way of forming very, very long chains. 763 00:38:03,848 --> 00:38:05,750 So on Wednesday, we'll talk about what 764 00:38:05,750 --> 00:38:07,118 you can do with these chains, how 765 00:38:07,118 --> 00:38:09,086 you can modify the properties, kind like we do with glass. 766 00:38:09,086 --> 00:38:10,655 We talked about the fundamentals of glass, 767 00:38:10,655 --> 00:38:12,390 and then we talked about engineering it. 768 00:38:12,390 --> 00:38:13,791 On Wednesday, we'll talk about how 769 00:38:13,791 --> 00:38:17,695 to engineer the properties of these polymers. 770 00:38:17,695 --> 00:38:20,564 But right now, I want to just focus on how to make them. 771 00:38:20,564 --> 00:38:22,733 And so in condensation polymerization, 772 00:38:22,733 --> 00:38:25,703 the goal is also to make these super long strands, 773 00:38:25,703 --> 00:38:28,239 but you do it with two different starting molecules 774 00:38:28,239 --> 00:38:30,508 and no initiator. 775 00:38:30,508 --> 00:38:32,043 So how does that work? 776 00:38:32,043 --> 00:38:34,278 Well, I'll take a-- 777 00:38:34,278 --> 00:38:36,681 I'll get to nylon in a sec. 778 00:38:36,681 --> 00:38:38,182 But first, let's just take something 779 00:38:38,182 --> 00:38:40,384 called the dicarboxylic acid. 780 00:38:40,384 --> 00:38:43,587 And what I'm going to do is I'm going to leave a box inside. 781 00:38:43,587 --> 00:38:45,756 And I'm going to say that could be something. 782 00:38:45,756 --> 00:38:46,924 That could be something. 783 00:38:46,924 --> 00:38:50,328 But I know that on that something, I've got this. 784 00:38:50,328 --> 00:38:57,401 I've got a carbon, oxygen, and hydrogen, and on this side 785 00:38:57,401 --> 00:38:58,536 I've got the same thing. 786 00:39:03,407 --> 00:39:05,109 OH. 787 00:39:05,109 --> 00:39:08,479 So I've got the same thing on both sides. 788 00:39:08,479 --> 00:39:10,147 That's a dicarboxylic acid. 789 00:39:10,147 --> 00:39:12,616 It's carboxylic acid. 790 00:39:12,616 --> 00:39:17,488 Now, on this side, I'm going to have another mer, 791 00:39:17,488 --> 00:39:19,156 and it's going to be different. 792 00:39:19,156 --> 00:39:22,560 And this one, I'm also going to have a box. 793 00:39:22,560 --> 00:39:23,627 And over here. 794 00:39:23,627 --> 00:39:24,195 [SNEEZING] 795 00:39:24,195 --> 00:39:25,930 Gesundheit. 796 00:39:25,930 --> 00:39:27,932 I've got NH2. 797 00:39:27,932 --> 00:39:31,435 And over here I've got NH2. 798 00:39:31,435 --> 00:39:31,936 NH2. 799 00:39:35,139 --> 00:39:38,209 Emphasizing the N is what's connected to the box there. 800 00:39:38,209 --> 00:39:39,844 That's why I drew it that way. 801 00:39:39,844 --> 00:39:40,978 And that's called an amine. 802 00:39:40,978 --> 00:39:42,546 This is an amine. 803 00:39:42,546 --> 00:39:44,682 And this is called a diamine. 804 00:39:44,682 --> 00:39:47,051 So this is a diamine dicarboxylic acid. 805 00:39:49,720 --> 00:39:52,623 And what happens is when those two molecules-- so the box 806 00:39:52,623 --> 00:39:53,424 can be anything. 807 00:39:55,993 --> 00:40:01,899 The box can be whatever for now. 808 00:40:05,736 --> 00:40:08,672 If it's got those ends to it, if it's got 809 00:40:08,672 --> 00:40:11,242 the carboxylic acid and amine-- 810 00:40:11,242 --> 00:40:12,643 so on the one hand, the molecule's 811 00:40:12,643 --> 00:40:15,479 got these groups on the end, and on the other hand, 812 00:40:15,479 --> 00:40:18,449 it's got these, then what happens when I put them 813 00:40:18,449 --> 00:40:20,418 in solution together? 814 00:40:20,418 --> 00:40:24,188 Well, what happens is these two pieces react. 815 00:40:24,188 --> 00:40:25,656 These two pieces react. 816 00:40:25,656 --> 00:40:29,960 And so what you get is-- 817 00:40:29,960 --> 00:40:30,828 let's see. 818 00:40:30,828 --> 00:40:35,099 You've got C. Here's my box there. 819 00:40:35,099 --> 00:40:38,135 There's the O down there. 820 00:40:38,135 --> 00:40:42,173 And let's see. 821 00:40:42,173 --> 00:40:44,642 Now here's the carbon on this side. 822 00:40:44,642 --> 00:40:46,076 Oh, boy. 823 00:40:46,076 --> 00:40:48,412 I'm going to run out of room, and I don't want to. 824 00:40:48,412 --> 00:40:52,616 So I'm going to move over here. 825 00:40:52,616 --> 00:40:59,657 And recycle these boards so that I can draw it nice and big. 826 00:41:02,993 --> 00:41:07,798 So now what happens? 827 00:41:07,798 --> 00:41:08,732 So these are reacting. 828 00:41:15,105 --> 00:41:16,240 And so now what do I have? 829 00:41:16,240 --> 00:41:22,713 So I have C, double bond O. There's my carboxylic acid. 830 00:41:22,713 --> 00:41:24,548 There's the box from the left-hand molecule, 831 00:41:24,548 --> 00:41:25,749 the one on the left there. 832 00:41:25,749 --> 00:41:28,953 Here's another C, double bond O. 833 00:41:28,953 --> 00:41:30,120 But look at what's happened. 834 00:41:30,120 --> 00:41:33,657 I've formed a carbon-nitrogen link. 835 00:41:33,657 --> 00:41:35,092 We'll talk about that in a second. 836 00:41:35,092 --> 00:41:38,729 And then here's another box that came from the amine. 837 00:41:38,729 --> 00:41:42,933 And this is an NH. 838 00:41:42,933 --> 00:41:45,402 And then there'd be like another H there. 839 00:41:45,402 --> 00:41:47,137 And there'd be another H-- 840 00:41:47,137 --> 00:41:48,506 yes, another OH here. 841 00:41:54,211 --> 00:41:56,313 Yeah. 842 00:41:56,313 --> 00:41:57,214 Yeah. 843 00:41:57,214 --> 00:41:57,882 NH2. 844 00:41:57,882 --> 00:41:59,283 So I got that back. 845 00:41:59,283 --> 00:42:00,251 And what's happened? 846 00:42:00,251 --> 00:42:03,187 What's happened is I've made water. 847 00:42:03,187 --> 00:42:06,657 I've made water, plus I've connected these two molecules 848 00:42:06,657 --> 00:42:07,157 together. 849 00:42:09,994 --> 00:42:12,663 So if I want to be complete about it, 850 00:42:12,663 --> 00:42:14,031 I've got to add a water molecule, 851 00:42:14,031 --> 00:42:16,734 because that's what had happened in the middle here. 852 00:42:16,734 --> 00:42:21,071 The OH group saw the H on the NH2 group, 853 00:42:21,071 --> 00:42:23,107 and it said, hey, I want to make water. 854 00:42:23,107 --> 00:42:24,008 Can I do that? 855 00:42:24,008 --> 00:42:26,477 And then the carbon and the nitrogen 856 00:42:26,477 --> 00:42:27,511 were like, you know what? 857 00:42:27,511 --> 00:42:29,780 Let me check it out, internally. 858 00:42:29,780 --> 00:42:31,615 Let me check out my Lewis structure. 859 00:42:31,615 --> 00:42:34,385 And it's like, yeah, you can take the OH and the H 860 00:42:34,385 --> 00:42:38,222 and make water, because then we could connect and form 861 00:42:38,222 --> 00:42:39,990 this bond here. 862 00:42:39,990 --> 00:42:43,727 And that bond is called an amide link. 863 00:42:48,599 --> 00:42:49,366 That's that kind. 864 00:42:49,366 --> 00:42:51,635 And so I've formed a kind of bond between these two 865 00:42:51,635 --> 00:42:54,271 molecules that's a covalent bond. 866 00:42:54,271 --> 00:42:58,275 And this polymer is a class of polymers called polyamide. 867 00:43:02,513 --> 00:43:05,049 Because you can see now, OK, I've 868 00:43:05,049 --> 00:43:09,219 given off some water, condensation polarization, 869 00:43:09,219 --> 00:43:10,754 but I'm also now ready. 870 00:43:10,754 --> 00:43:13,123 I've got my carboxylic acid, and my NH, 871 00:43:13,123 --> 00:43:18,062 my amine groups there ready to go again. 872 00:43:18,062 --> 00:43:21,432 So if this side finds another one of these, 873 00:43:21,432 --> 00:43:23,701 it can attach and react. 874 00:43:23,701 --> 00:43:25,936 And if this side finds another one of those, 875 00:43:25,936 --> 00:43:26,937 it can attach and react. 876 00:43:26,937 --> 00:43:31,609 And it keeps going and going and going. 877 00:43:31,609 --> 00:43:34,478 In much the same way, it's just now instead of a radical, 878 00:43:34,478 --> 00:43:39,149 instead of initiating it by tearing an electron out, 879 00:43:39,149 --> 00:43:41,151 I simply have brought together two types 880 00:43:41,151 --> 00:43:45,155 of molecules that want to, in giving up water, 881 00:43:45,155 --> 00:43:46,590 react and form a bond. 882 00:43:46,590 --> 00:43:48,459 That's very powerful. 883 00:43:48,459 --> 00:43:52,062 It's very powerful, because I can do-- 884 00:43:52,062 --> 00:43:58,469 I can now, like I said, this can have whatever inside. 885 00:43:58,469 --> 00:44:01,305 So now it's a different way of thinking about it. 886 00:44:01,305 --> 00:44:02,906 Before we had the mer. 887 00:44:02,906 --> 00:44:04,608 And I could make the mer whatever I want. 888 00:44:04,608 --> 00:44:06,276 Just keep a double bond somewhere, 889 00:44:06,276 --> 00:44:08,112 and I can make a polymer. 890 00:44:08,112 --> 00:44:09,713 That's a lot of flexibility. 891 00:44:09,713 --> 00:44:12,816 Now, instead of keeping a double bond, 892 00:44:12,816 --> 00:44:15,786 just keep these amine and carboxylic acid groups there, 893 00:44:15,786 --> 00:44:18,122 and I can put anything inside the boxes that I want. 894 00:44:18,122 --> 00:44:21,558 Again, massive tunability. 895 00:44:21,558 --> 00:44:24,895 And one of the funnest things to do is the nylon rope pull. 896 00:44:24,895 --> 00:44:25,829 We couldn't do it. 897 00:44:25,829 --> 00:44:29,833 Apparently, it's a little dangerous. 898 00:44:29,833 --> 00:44:36,273 Nylon is when the box winds up having a carbon chain in it. 899 00:44:36,273 --> 00:44:40,077 Six carbon atoms. 900 00:44:40,077 --> 00:44:42,379 And when this has six carbon atoms 901 00:44:42,379 --> 00:44:46,850 and this has six carbon atoms, that's 902 00:44:46,850 --> 00:44:51,989 called nylon 6,6, which some of you may have seen. 903 00:44:51,989 --> 00:44:57,695 So you get nylon 6,6, or sometimes it's just called 66. 904 00:44:57,695 --> 00:45:04,501 It's six carbon atoms in the boxes. 905 00:45:04,501 --> 00:45:06,937 You can imagine you can make 6,8, 4,6. 906 00:45:06,937 --> 00:45:07,771 You can play around. 907 00:45:07,771 --> 00:45:10,207 You can put lots of things in those boxes. 908 00:45:10,207 --> 00:45:11,942 The nylon rope pull is such a cool thing. 909 00:45:11,942 --> 00:45:13,377 I had to show you a video. 910 00:45:13,377 --> 00:45:14,578 Here's what you've got. 911 00:45:14,578 --> 00:45:17,581 You've got one molecule in solution on the top. 912 00:45:17,581 --> 00:45:18,115 You can tell. 913 00:45:18,115 --> 00:45:19,683 It's the slightly lighter liquid. 914 00:45:19,683 --> 00:45:21,618 And the other one on the bottom. 915 00:45:21,618 --> 00:45:25,923 The amines on one side, these carboxylic acid on the other. 916 00:45:25,923 --> 00:45:26,724 This is nylon. 917 00:45:26,724 --> 00:45:29,059 So the box is six carbon atoms. 918 00:45:29,059 --> 00:45:30,561 Now, what's happening? 919 00:45:30,561 --> 00:45:37,434 At the interface, this reaction is occurring. 920 00:45:37,434 --> 00:45:40,270 So what I can do, and I'll play this. 921 00:45:40,270 --> 00:45:45,409 Or what this person can do is put a little piece of glass 922 00:45:45,409 --> 00:45:50,481 stir in there and pull nylon out. 923 00:45:50,481 --> 00:45:52,916 So watch how he does this. 924 00:45:52,916 --> 00:45:54,384 So you get it started. 925 00:45:54,384 --> 00:45:59,123 There is a piece of solid coming out of two liquids. 926 00:45:59,123 --> 00:45:59,823 What's happening? 927 00:45:59,823 --> 00:46:02,359 As he pulls it, more is reacting and forming 928 00:46:02,359 --> 00:46:04,795 more of these chains. 929 00:46:04,795 --> 00:46:09,266 And you can just keep going and going and going. 930 00:46:09,266 --> 00:46:10,734 What's so cool about this is you're 931 00:46:10,734 --> 00:46:13,237 literally creating this solid with functionality 932 00:46:13,237 --> 00:46:15,506 that's tunable out of these two liquid baths. 933 00:46:15,506 --> 00:46:17,941 It's all happening at the interface 934 00:46:17,941 --> 00:46:21,044 where the two molecules, the amine and the carboxylic acid 935 00:46:21,044 --> 00:46:21,812 can see each other. 936 00:46:21,812 --> 00:46:22,446 And there you can see it. 937 00:46:22,446 --> 00:46:24,782 I wish you didn't have the text there, but look at that. 938 00:46:24,782 --> 00:46:27,084 You're pulling a polymer right out of the interface 939 00:46:27,084 --> 00:46:28,685 between two liquids. 940 00:46:28,685 --> 00:46:30,988 That's how nylon is made. 941 00:46:30,988 --> 00:46:34,858 And again, this had an incredible impact 942 00:46:34,858 --> 00:46:36,493 on so many applications. 943 00:46:36,493 --> 00:46:37,928 I thought I'd show you this one. 944 00:46:37,928 --> 00:46:40,964 That's the first line in New York 945 00:46:40,964 --> 00:46:43,634 to buy stockings, nylon stockings. 946 00:46:43,634 --> 00:46:45,169 And it's going on and on and on. 947 00:46:45,169 --> 00:46:47,504 Of course, then there are a few other applications, too, 948 00:46:47,504 --> 00:46:51,241 like parachutes, and many, many, many more, because again, it's 949 00:46:51,241 --> 00:46:53,710 a whole other way of making polymers. 950 00:46:53,710 --> 00:46:56,213 Now, I'll talk more about this on Wednesday. 951 00:46:56,213 --> 00:47:01,819 But in your goody bag, you've got old school fun. 952 00:47:01,819 --> 00:47:04,321 And we'll talk about this in the context of the things we're 953 00:47:04,321 --> 00:47:06,323 going to learn more about polymers and polymer 954 00:47:06,323 --> 00:47:07,758 engineering. 955 00:47:07,758 --> 00:47:09,560 See you guys on Wednesday.