Picture of Starch Plastic 2.0- Pressure Cooker Hacking
So you have done or were interested in my first instructable on potato plastic and now your looking for something that will yield better results and a little more danger, well here it is. First and foremost I strongly recommend that you approach this project only if you are willing to accept some safety rules, and I will go over those in another step. The basic premise behind making a starch based plastic is to get a starch crammed full of polymers and nothing else, as impurities would detract from the strength properties we want. To do this we are going to have to enter into the realm of modified food starches. For this instructable we will be using a starch that has been modified to have an amylose content of 70% as opposed to the normal 20% found in most starches. The product is called Hylon VII from National Starch Food Innovation. The reason we want a high amylose content is because amylose is "is a planar polymer of glucose linked mainly by hydrogen bonds. It can be made of several thousand glucose units. It is one of the two components of starch, the other being amylopectin". So basically it makes really long polymer chains (good), and if you don't fully understand this go check out my first instructable on Potato Plastic. There is a catch 22 however that puts us in quite a pickle metaphorically speaking, go to step 1 to discover this conundrum.

Heres a video of me doing some strength tests of thick and film-like pieces of my awesome plastic


Thinking about possibly a checkvalve steam system, continuous feed. Think your coffee maker. Tank of precursor, checkvalve (brass rated at 120psi!), short iron or brass steam pipe (again 120psi rated) and then a mechanical or solenoid driven valve, apply heat to center via propane. I suppose you could have a mechanical valve on the outflow, so when the temp rises above 154 or so (or pressure), you bleed out some of the newly formed plastic, close the valve, cut the temp briefly and let it suck in a new batch... you could automate it to generate as much as you want without the hour long wait times for it to come up to pressure.

seamonkey52 years ago
is it possible to use adhesive to bind the potato plastic to material/fabric? and if it would hold?
Brandon121233 (author)  seamonkey52 years ago
This starch polymer behaves as an adhesive already. You can impregnate the fabric with the gel and let it dry to produce a reinforced polymer composite. I did this in my video with gauze to produce a very strong and flexible composite material. Let me know if you have further questions.
I am curious how you got to buy Hylon VII, ive searched through the net but i can't find the way to get to it. Any help?
legionlabs6 years ago
I was researching an unrelated process when I stumbled upon this, I thought you might find it interesting:

Given only potatoes, you might be able to increase the purity of the starch for your process by removing cellulose using this reagent, which can be made from commonly available materials:


You can reuse the reagent by precipitating the cellulose out by acidifying the mixture, filtering out the cellulose, and making the reagent basic again.

You can make other plastics out of the extracted cellulose, though I don't know enough to say exactly how.
You can make plastic from the cellulose by nitrating it. Nitrocellulose is soluble in acetone and the first films used in movies were printed on nitrocellulose.
Cellulose nanocrystals can be used to make plastic 3,000 times stronger, apparently. www.newswise.com/articles/cellulose-makes-plastic-3000-times-stronger
Brandon121233 (author)  duct tape5 years ago
problem #1, nitrocellulose also happens to be rather flammable if not explosive, as seen in Tarentino's Inglorious Bastards.

problem #2 crap like that gets leaked to the techie press all the time, and I don't buy it for a second. First because there is no research paper associated with that story, thus no supporting evidence. Secondly because its from a college that has little or no know research coming out of it. Finally simply because the story was first reported three years ago, and three years later not even a peep has been mentioned about a start up company or patent being produced from this "breakthrough".
For future reference, don't believe everything you see in the movies. But I suppose I shouldn't believe everything on the 'net. Yes, nitrocellulose is very flammable as I have made it before. It's being flammable is why it was phased out ultimately for acetate or safety film.
Brandon121233 (author)  duct tape5 years ago
I don't believe everything I see in movies, but in this case I myself have had experience burning old nitro film, and from first hand seeing it rapidly go up in flames, I can say that the scene is rather accurate...
Another fun fact: Nitrocellulose is also the main component of modern smokeless gunpowder, and can be mixed with nitroglycerin to form a gelatin dynamite.

"Flammable" is potentially a major understatement, depending on what form it is in.
Nitrocellulose plastics are used to make ping pong balls, which are in fact highly flammable. The process was invented ~1850, or so claims Wikipedia.

As for the tech press, you're probably right. I bet you can get them to publish anything of the form "Nano(noun) (noun)". Wacky news libs!

In my opinion, small colleges don't get good publications even if they do produce good research; and large colleges get away with producing crap all the time (not that they don't produce good stuff too). MIT ran a study of this effect; while I don't have a link handy this is more or less the same thing (and hilarious): http://pdos.csail.mit.edu/scigen/    (Warning: Not thesis supervisor safe)

But yeah, no research paper = no science and makes baby Newton cry.
Brandon121233 (author)  legionlabs6 years ago
thanks for the suggestion, I'll add that to the optional section on my first instructable for making your own starch with potatoes
Brandon121233 (author)  Brandon1212336 years ago
Added it to step two here http://www.instructables.com/id/S2DICE5F46WOFIN/
thanks again
Have you tried this with store bough corn starch?
DaboJones6 years ago
Good job, interesting product! How well does it age? Does it noticeably fall apart within a month/year? Any progress on removing bubbles? This really could save me some cash for getting things pre-fabbed.
vanmankline6 years ago
I'm hoping you may be able to supply more info on the plastic you demonstrate and its uses. How thick is the sheet of plastic pictured over the word "clear"? To what thickness does the product keep that level of clarity? Have you found any transparent dyes for the plastic? Can it easily be cast? If so, do you have any suggestions on mold materials? does it degrade quickly in UV light? Does it weather well? Thank you for any info you may have.
robobadger6 years ago
have you tried making an aluminum oxide ceramic with this? You can use sand blasting Aluminum Oxide with it to increase the strength possibly. Lawrence Berkeley National Laboratory in California scientists found that by freeze drying the aluminum oxide resin mixture then heating it under pressure they got an extremely strong ceramic. Might be worth a try with your potato plastic.
darksparc6 years ago
You should be able to get rid of the bubbles by pulling a vacuum on the container. You will need a vacuum pump as a shop vac will not take the atmosphere down enough. As the pressure in the container reduces the bubbles will expand and pop. All the smaller bubbles will be pulled to the surface.
yokozuna6 years ago
This is very good instructable. If the mold was heated and/or pressurized, would that get rid of the bubbling problem? Have you used this for any practical applications?
wingbatwu6 years ago
I'm not an explosives specialist, but in the event of an explosion, steam and shrapnel are not your only concerns... the pressure wave could hurt you pretty badly as well
mweston6 years ago
Haha,I love mythbusters! By the way this is pretty cool :-)