Cup o'Joe-Stretching the Science of "Stretch Armstrong"

[00:00:00]Today, we're going to continue my exploration of firsts.

[00:00:05]You know, I like to introduce you to to things that I do for the first time.

[00:00:10]Well, back in 1976, the Kenner toy company introduced a toy called Stretch Armstrong. You could stretch this guy and it would bounce back to his original shape.

[00:00:21]I didn't know about it back then, but when I started lecturing about polymers, I became interested in applications in diverse areas, including toys.

[00:00:34]And just recently, I started to look into this again and I thought it would be interesting to actually have a Stretch Armstrong to see what he was like and so that I could talk about his interesting chemistry.

[00:00:50]So, I explored eBay and eventually I found someone who was willing to sell me a vintage one.

[00:00:58]And I've not opened it yet.

[00:01:01]So, let's do this. Here's my first look at Stretch Armstrong.

[00:01:12]Okay, ready? Here we go.

[00:01:15]Ah!

[00:01:17]Here he is, just like I've seen in the pictures.

[00:01:22]And uh looks like a wrestler and indeed he does stretch.

[00:01:31]Just like he is said to be able to to do.

[00:01:39]Oh, so that's Stretch Armstrong. Quite happy with this guy. He's just what I expected.

[00:01:45]Now, what is he made of? That's where interesting chemistry comes in because really we can only guess. Toy manufacturers do not have to disclose exactly what their products are made of.

[00:01:58]So, I've done some searching. I've looked at patents, and I think I have a a pretty good idea.

[00:02:03]Uh his inside is made of um uh corn uh syrup.

[00:02:10]Uh probably with some little plastic beads as as well. But, corn syrup is interesting. Uh it's uh made from corn starch. You use an enzyme that breaks it down into glucose and small polymers of glucose.

[00:02:25]And uh a a viscous solution of this uh will flow, and that's what's happening. The solution inside is flowing when when I stretch.

[00:02:35]And [snorts] uh being uh what we say viscoelastic, it will go back to its original uh position. But, that of course is dependent on the outside skin.

[00:02:47]Uh which uh I think is made of a uh thermal elastic material. Uh this is a a mix of a plastic and an elastomer. So, rubber, for example, would be an elastomer that stretches, and plastics are substances that could be molded and will retain their their shape. Uh I think most likely we're looking at polyurethane as the elastomer uh part uh of this, but I can't really be absolutely sure. It's probably uh uh a polyurethane that is mixed with uh actual rubber.

[00:03:23]Uh and his head is made of a solid plastic. I would think that that is probably PVC, polyvinyl chloride. So, uh there is uh our friend uh Stretch Armstrong. And uh I think I'm quite happy with uh with him. Now, he is not the only stretchy kind of uh of toy. I do have uh some others, and uh especially like this guy.

[00:03:54]Uh he is sold as sort of a stress relief uh guy, and you can stretch him, and he bounces back to his original shape.

[00:04:07]Gorilla.

[00:04:08]Now, this uh is not made with uh corn syrup inside. This is made with sand.

[00:04:15]Very fine particle sand, probably coated with a polysiloxane material, a polymer, a silicone.

[00:04:23]Uh again, I'm just guessing based on uh having worked with some uh polymers uh that coat coat sand.

[00:04:33]And the outside layer, again, I think is a thermoelastic material. It's a mixture of some kind of of of rubber, uh maybe um styrene butadiene uh mixed with uh some other plastic, but again, it's it's hard to say. But, you can feel on the inside that that he is kind of sandy, and he stretches.

[00:04:59]And he will eventually go back to his uh or original uh shape uh thanks to the uh elastomeric property and the sand that is uh inside. And uh yeah, he does relieve some stretch when you play with him.

[00:05:18]And as you might expect, I of course also have to have a stretchy duck. In fact, I have two different ones.

[00:05:28]And uh this is uh really quite different because inside is is a gel.

[00:05:34]Now, gels are materials that are are made with water and some chemical that thickens the water. Uh things like agar, which is extracted from seaweed, or pectin that you use in in in jams uh or polyacrylates.

[00:05:52]These are substances that can gel water. And there are many others.

[00:05:58]Collagen, of course, is something that can be used when you make make Jell-O.

[00:06:03]So, inside of this, I I think probably is a polyacrylate type of gel. And the skin, once again, is made of an elastomer.

[00:06:15]And as you can see, this duck stretches and I'm I don't want to overdo it.

[00:06:22]And I have this little guy as well.

[00:06:26]Again, made of a thermal plastic elastomer. And inside, I suspect is is a gel that is made of poly polyacrylate or or maybe a different kind of acrylamide.

[00:06:43]>> [snorts] >> So, anyway, pretty interesting chemistry in in all of these. I'm not exactly sure what is inside, but I don't want to do autopsies on my poor stretchy guys to look more deeply into it. But anyway, it gives you a bit of an idea of what is involved. And it's it's unfortunate that toy manufacturers don't have to disclose exactly what is in there. I I wish they did because then we could talk about the specific chemistry. But in case, I'm pretty happy with my uh new Stretch Armstrong and my gorilla that uh really can stretch. And kind of gives you exercise and uh also reduces stress. And then, of course, I have my duckies. And uh I would love to know what inside of them. But I'm certainly not going to uh make any kind of incision in my little friend.

[00:07:51]And uh that for today is our cup of Joe and uh what we've learned from uh stretching uh the science of Stretch Armstrong.