Step 3: Mix it Up !
Now that you have gathered all the necessary materials and ingredients, its time to mix up a batch of potato plastic. A note to younger viewers: be sure to have a parent with you when using the stove, I don't want you to burn down your house because of this instructable! Also, beware of the starch plastic resin when you are pouring it into a mold, it is very hot and will burn you if it gets on your skin, you can never be too cautious with boiling hot substances.
1) Measure out 60 ml (4 tablespoons) of cold water and pour it into the beaker or container your heating the mixture in.
2) Measure out 10 grams (or about 1 tablespoon) of starch ( the potato / corn starch you made or bought) and add that to the water.
3) Add 5 ml or about 1 teaspoon of acid (vinegar) to the mixture.
4) Add 5 ml or about 1 teaspoon of glycerin to the mixture, more glycerin will make it softer and more flexible, less will make it harder and stiffer but more brittle.
5) If a colored plastic is desired, add in the food coloring now. About 5 drops is good enough.
6) Turn the burner on low and constantly stir the mixture. When it starts to thicken up turn the heat up to medium and stir even more. When it starts to boil, keep boiling it for 5 minutes. You want it to be very clear and sticky (not like toothpaste though, think flubber)
7) You should now have a "gooey" substance that you can pour into a mold, or you can pour it onto a sheet of aluminum foil/silicone heat pad to dry.
8) Depending on humidity, it should take about 1 day to dry in a sunny place. You can dry it faster by putting it in an oven set to 150 F for 1-2 hours.
1) Measure out 60 ml (4 tablespoons) of cold water and pour it into the beaker or container your heating the mixture in.
2) Measure out 10 grams (or about 1 tablespoon) of starch ( the potato / corn starch you made or bought) and add that to the water.
3) Add 5 ml or about 1 teaspoon of acid (vinegar) to the mixture.
4) Add 5 ml or about 1 teaspoon of glycerin to the mixture, more glycerin will make it softer and more flexible, less will make it harder and stiffer but more brittle.
5) If a colored plastic is desired, add in the food coloring now. About 5 drops is good enough.
6) Turn the burner on low and constantly stir the mixture. When it starts to thicken up turn the heat up to medium and stir even more. When it starts to boil, keep boiling it for 5 minutes. You want it to be very clear and sticky (not like toothpaste though, think flubber)
7) You should now have a "gooey" substance that you can pour into a mold, or you can pour it onto a sheet of aluminum foil/silicone heat pad to dry.
8) Depending on humidity, it should take about 1 day to dry in a sunny place. You can dry it faster by putting it in an oven set to 150 F for 1-2 hours.
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This is interesting and I really need your help. Can i get a copy of the research paper of this ? mermaidsandpixiedusts@gmail.com
Thanks.
I am wondering if you could send me your research paper as well. I am trying to reinforce my potato plastic as well, so far in vain.
isabell.mysyk@gmail.com
Thank you so much and keep up the awesome work!
I really like the idea of your project. I really want to make that as our project too; however, we don't have tensile tester in our school. My plan originally is to make a plastic bag ( which I don't know how to accomplish) Next I will test the strength of the plastic bag in carrying things. I don't know how to logically do the testing in testing the strength. Can we do that without the tensile tester? I mean is testing the tensile the same with testing the ultimate strenth the plastic can handle? What can you suggest as the best step that we could take? and about the fiber thing that you add to your plastics.. what are they for? What are fibers? As I understand it they can help strengthen the plastic. Would the existence of the fiber somehow affect the biodegradability of the plastics? Cause you see, aside from the strength of the plastics, * durability* , *practicability* we also aim to test its biodegradability by burying it in soil and observing it. Do you think it can really be decomposed. I have read in the net a certain study claiming that after two weeks, she had seen her plastics decompose by fifty percent. I don't what that fifty percent mean. Could that really possibly happen? I would really appreciate if you can answer all my questions and offer my advice. I really want to succeed on this project. What makes this project hard for me is the fact that it's a group project. (whew...)
Natural fibers are the individual strands that make up cotton clothing (the filaments on the threads that tear off your shirts) or that make up different types of strings. In nature, they make up plants stalks, etc. When amylose & amylopectin fuse, natural fibers will strengthen that bond. As you see in my study, the thickest, most tangled fiber did the best job of reinforcing the plastic.
I worked at a plastics company for this project, so I had access to a tensile tester. Get in touch with a nearby company or university, no doubt they will have a tester that you can use. They are easy to operate. As for the fibers, I also used a grinder at the company lab to grind my fibers down, but you can try a coffee grinder... not sure if it'll work though.
Addressing the testing if you cannot find a tensile tester-- I think that you could make bags by coating two glass plates and then connecting the bottoms of the plates? Experiment with this. I did not try making plastic bags, it is probably more difficult. You could always try a less exact method of measuring strength/durability by placing small weights inside the bags and seeing how many the bag can hold. Definitely less exact and the chance of scientific error will increase, but make do with what you have.
I have sent you the paper, let me know if you have other questions. I encourage you to seek out local plastic companies or contact professors universities. Most labs have tensile testers. Good luck.
please, please, please!
i dont know how i could use or extract the fibers for my potato plastic
it seems to have worked for you so could you tell me?
thanks
You may be adding too much plasticizer, or you may just need to spread the plastic thicker. Experiment with types of plasticizer, because that will dictate those kinds of properties. I use cotton, jute, and hemp fibers in my study, and hemp performed the highest in resisting water degradation as well as in strength tests. I will share my methods with you here, feel free to ask if you have more questions.
"Phase I of the experiment involved the creation of samples for testing. A slurry of 2 tablespoons of starch and 8 teaspoons of water was created. If applicable, 6g of fiber was added and mixed into the slurry until it became relatively homogenized. Then 1 teaspoon each of glycerin and vinegar were added to the slurry. The slurry was heated at low on an electric stove, then when it began to steam, turned up to high and allowed to boil. Then the slurry was poured and spread onto two glass plates with non-stick surfaces. The plates were then pressed together to create a flat layer of plastic. This process was repeated for each fiber, and for the control plastic without fiber. After the plastic had partially solidified, one glass plate was removed and the plastic allowed to air dry until completely solidified."
"The results of the tensile testing supported the hypothesis that the hemp fiber reinforced plastic would demonstrate the greatest tensile strength. The reinforced plastic had an average tensile stress at break of 2138.63 psi. A Kruskal-Wallis test, which compares the differences among medians, conducted on the tensile strengths of hemp, jute, and cotton, and non-reinforced (control) plastics showed that the differences are statistically significant (k=10.3846, p.= 0.016). As shown in Figure 5, the hemp-reinforced plastic was significantly stronger than the other plastics. The fiber-reinforced plastics were also significantly stronger than the non-reinforced control. As shown in Figure 6, though the hemp plastic failed quickly under tensile stress, it was a brittle failure, and the plastic held a large load."
So since the plastics suffered brittle failure, the problem was the plasticizer, and I suspect that you are having the same problems. Following these methods you should be able to create plastics that stay together and are strong.
could you use sorbitol chewing gum? Maybe chew the gum 10-15 seconds and spit out the juice?
Are there soap brands that are almost pure glycerine? Dish detergent?
Other recipes here use a lot more starch, but with vegetable oil. Is the main reason that: Glycerine saves money if you are making a lot? Or its a lot better quality?