Instructables

Making BioPlastics, Environmentally Friendly Plastics

This is my first instructable so please try not to criticize to harshly.

BioPlastics are plastics that can be made out of common household products.
These are to the environment in that they contain no petroleum unlike usual plastics such as tupperware etc. Also instead of taking about 100 years to fully decompose it only takes about 7.

There are probably other instructables about BioPlastics out there, but I made some for a school project so I decided to make an Instructable



 
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Step 1: Ingredients

Here are the ingredients that I used...

-Corn starch
-Water
-vegetable/Canola (Optional)
-Wax Paper (optional)

You will also need a microwave.
And measuring tools

Step 2: Mixture

The Ratio I mixed with was 1 part corn starch and 1 part water. Feel free to change this based on the use of your plastic.

For a more rigid plastic, add more corn starch.
For a more flexible/ squishy plastic add more water.

I mixed them in a sandwich bag.

If you want to add in some vegetable or canola oil (I used canola) and it will help keep it together a little bit
for every 2 cups of MIXED water and corn starch I added 1 tablespoon of oil. But of course you can change this based on your intended use of the plastic.

Make sure to get all the bumps of corn starch out you want it to be completely dissolved
It should look a bit like milk.
Fredfly1 month ago

thanks! I'm going to use this for my quad copter base

first, This looks AWESOME, also, what would the substitute time be for a convection oven (regular oven) (i don't have a microwave, sad, I know). BTW, how hard is the plastic when cooked (comparisons).
I wouldn't use a conventional oven... The transfer of heat in an oven heats the outside much quicker than the inside. This will cause all sorts of mayhem with the shape and can cause it to basically rip itself in two :(
lyka112 years ago
I really need to know if there would be side effects when i add shrimp shells, please do help me.
Did you ever try it? My guess is that the chitin in the shells would make it harder but probably more brittle... Please let me know if you tried this, I'm curious now
amozer1 year ago
Great idea for my 1st year students (secondary school, age 15). Majbe we could use aslo food dyes for more attractive products?
jbaker222 years ago
I made a bio plastic similar but with vinigar and gluconate it stayed a gel. For a day and I through it away. Did I just need to wait longer?
Geli125 years ago
I Want to make small billiard balls. This plastic is good for that idea? Geli
I would have to say no. This stuff is pretty soft, and the balls bashing each other would warp them pretty badly before too long.
sharlston4 years ago
if it decomposes in 7 year does that mean we cant keep them for more than 7 year?
Decomp usually only occurs when things are exposed to high levels of unfriendly conditions. Basically, keep it indoors. Should be fine for a while. 7 years is a pretty long time to be used consistently for a lot of plastic products.
lyka112 years ago
Do you think it would come out right if i add shrimp shells in the ingredients?
lyka112 years ago
Good day. I'm a junior highschool student and in our Research subject, every one should pass his/o r her own proposal. My proposal was using shrimp shells as an additive in making plastics. As i browse through the internet, i noticed that your methods are easy so i decided that i will used them and just add the shrimp shells. Do you think it would still come out right? is my proposal possible? what could be the side effects of adding shrimp shells? Thank you. May you reply quickly for i really need your help.
gregstevens2 years ago
Hi! Great instructable.

It might also be worth mentioning that there is an entire website dedicated to providing current news and answering student's questions about making bioplastic. It's at

http://green-plastics.net/

It has recent articles on everything from why certain ingredients matter (e.g. why some recipes call for vinegar and water) to how to get certain types of results (e.g. how to make a hard, water-proof bioplastic in your home). It would be great if you could let your readers know about this resource in your instructable!
What do you think about using vinegar? I saw a recipe that uses vinegar to break up the shorter amylopectin polymers, leaving the much longer amylose polymers and making the plastic less brittle. The process is apparently called "acid hydrolysis". He also uses glycerin for a similar purpose.
Here's the video.
By the way, I'm really new to this subject. I only started researching it today.
thanks for the rep
how flexible is this stuff, exactly? i've seen recipes for producing this stuff on the stove, but there have been so many different results.... depending on the amount of oil added, would this material be appropriate for making something like, say, a mold tray? or does it come nicely out of molds?
JohnJY4 years ago
I put my batch in the microwave,  it turned hard instantly, and I couldn't pour it into my mold, I can get around that, but when I make large batches, It likes to break open, like airs trapped inside, how do I get the air out?
ebenalart4 years ago
try to add some wood glue that get more strenghth use   to make wings for rc plains  
garrett104 years ago
Omg, i did this before this instructable was made and it didnt work. thanks for adding oil to the mix. mine was too brittle at first
robokid4 years ago
cool,great,descriptive all you could want in an Instructable! I'm using this to make brackets for a robot . do you think it could hold up 40oz or so?
nrepak (author)  robokid4 years ago
thanks And im sure that if your bracket was built right that it could support the weight
jtobako5 years ago
How do you control shrinkage? Mine always drys at the surface, then the interior opens up like Carlsbad Cavern...
nrepak (author)  jtobako5 years ago
to keep it from drying on the outside too fast you could probably just put a damp paper towel over it.
jtobako nrepak5 years ago
The problem is that the surface drys and sets up while the center is still wet. When the water in the center drys out, it pulls the still soft materiel away from itself, creating a huge hole. What has to be slowed isn't the evaporation rate, it's the setup rate...but then you couldn't use it...
nrepak (author)  jtobako5 years ago
Are you heating it in a microwave? because I don't think you wouldn't have this problem if you were, considering that they heat from the inside out.
you could put it in the oven put lower temprature
CafeT nrepak5 years ago
I don't believe that's correct. The mixture is high in water content, I'm guessing the starches might absorb the microwaves, too, and there's two cups of liquid in the microwave. Outside regions would probably heat up first.

http://www.straightdope.com/columns/read/2118/do-microwave-ovens-cook-from-the-inside-out
jtobako CafeT5 years ago
The outside still drys first-evaporation is faster than the water can get out, and the steam that forms inside still forms bubbles.
AACRJimbo5 years ago
This sounds really awesome and useful, could you be more descriptive possibly of the end result material? I am making large pieces of a game board and would like to use something like this. The way you described it, they are not very heat resistant? Can they be milled, sanded, shaved, drilled ect after they are dried?
nrepak (author)  AACRJimbo5 years ago
Of course I let one dry for a week and it was not to brittle and I could easily drill it and cut it. Just make sure to make it bigger then you want it because the outside will crack a little
Browncoat5 years ago
Any problem if you added a few drops of food coloring?
nrepak (author)  Browncoat5 years ago
I dont think it would matter that would be pretty cool to
jtobako nrepak5 years ago
Regular food coloring looks very pale, you need the industrial strength ones for cake decorating to get good, dark color.