Introduction: DIY Bio-plastics

Bio-plastics are a great alternative to traditional plastics, which are often composed of petroleum products. As years pass, we have less and less petroleum available to us, so it is important to find a suitable alternative. You can't beat the light-weight, low-cost applications of plastic products, so many companies are experimenting with making a similar product out of a more renewable product. Starch plastics are a good alternative, because corn is readily available, and when the plastic is done being used, it can be broken down rather than sent to a landfill.

This is a simple recipe that can be made in any kitchen, with common items often found in the average pantry. It can be a fun experiment for the classroom, as well as at home. The main purpose of this is to garner interest in the subject, so that future scientists will be able to develop more sustainable ways to make plastic products.

This experiment is quick, simple, and won't make a big mess!

Step 1: Step 1: Supplies

Bio-plastic ingredients:

1. 1 tbl cornstarch

2. 1 tsp vinegar

3. 1 tsp glycerin

4. 4 tbl water

Helpful tools:

1. Spatula

2. Small pot

3. Cookie sheet

4. Aluminum foil (optional)

5. Measuring cups

6. Stove top (or hot plate)

These are all ingredients that can be found in most kitchens, aside from the glycerin. Glycerin is used as a plasticizer in this application, but is often an important additive in lotions and other skin care products because of it's hydrating properties.

Different ingredients will affect the final outcome in different ways. For instance, glycerin will make the plastic more flexible. The acetic acid in vinegar helps the starch to dissolve easily, because it adds ions to the mixture. Vinegar is a much more readily available ingredient than ammonium acetate, which would be used in a larger scale commercial bio-plastics operation. Water is used as a solvent, also to denature the starch. That way, a thin film can be created as a final product.

Step 2: Step 2: Add All Ingredients to Pot

The order does not matter. Simply measure all ingredients (this is not rocket science, so it doesn't need to be exact) and mix them together in the pot. Stir until combined, then turn on stove to low/medium heat.

Step 3: Step 3: Heat Up the Mixture

After the heat is turned on, the mixture should be stirred regularly to avoid clumping. It will be a milky color at first, but will soon get thicker and turn slightly translucent. It is important to keep the heat low so that the heat is equally distributed throughout. This process happens fairly quickly (the pictures above were taken ~30 seconds apart), so keep stirring until the mixture thickens!

Step 4: Step 4: Turn Off the Heat!

Once the mixture is easily scoopable, turn off the heat! Stir a few more times, then pour/scoop the mixture onto an aluminum foil lined cookie sheet. The foil is optional, but it will be easier to remove later when the plastic is dry.

Step 5: Step 5: Form the Plastic

The mixture will feel similar to hair gel when it is first on the pan, and will need to cool a bit before it can be formed. Let it sit for a minute or so, then spread with a spatula on the foil. Over the next 15 minutes, the plastic will begin to harden and not stick to fingers when touched, but it will still be soft. The plastic should be left alone for several hours, until completely set.

If you wish to form the plastic into a small bowl or other simple shape, it can be left on the foil for about an hour, then formed almost like playdoh. After forming, set it back on the foil and allow to dry for several hours or overnight. Resist the urge to touch the finished product throughout the drying process, as it will still be soft.

Step 6: Bio-plastics Experiment

The great thing about this particular project is that it will dissolve in hot water and is made from materials that will not harm the environment further. If a small child or pet were to chew on your home made bio-plastic, they would not be harmed in any way (aside from it being a possible choking hazard). This is because all of the ingredients are completely safe for consumption. There are a great deal of positive aspects to these environmentally friendly plastics, and I encourage you to continue researching or trying other plastic recipes.

Thanks for reading!

Comments

author
CheckYourGages (author)2015-04-21

This is really cool, and I love how environmentally friendly it is! Once it's set, how hard is it? Could I form a phone case out of this that wouldn't deform in my pocket?

author

This particular recipe would definitely deform in your pocket, since it is susceptible to moisture, there are other recipes that can be heat treated for stronger, harder plastics. Try to find a recipe that doesn't use glycerin, which will create a more durable and less flexible plastic

author

Jordan,

I know its been 2 years, but would you still happen to know those heat treated and stronger plastics?

author
UtopianKing (author)2017-06-14

I'll definitely try this the first chance I get.

Will post results, but it will take time.

#Dear

author
Sammy A (author)2016-10-23

When you say a tsp of glycerin, is it pure 100% glycerin or a 1% solution?

author
UtopianKing (author)Sammy A2017-06-14

The bottle on the picture says 100% pure, so probably a tsp of whatever is in that bottle. Which would be 100% if you can trust the label on the bottle (Which is not always something you can do)

author
dominicpaul21 (author)2016-07-06

its very useful

author
Na101 (author)2015-12-26

epicnessness

author
miked2001 (author)2015-04-23

Despite all the "This is not new" I must laud you for this information and simple methodology. I had never seen this before, probably because I never thought about it, so I loved reading this. I actually thought of a use for this at work until I read about the "Not Water Proof".

I make electrical harnesses that need to be potted and often I just use hot glue. If this were a little better I could pour it into my molds and I would look like a hero. (I work for an environmentally friendly transportation company).

You have piqued my interest and will look a little deeper into this idea.

Thank you

author
bar.spartan (author)miked20012015-05-10

Hi mate, what about mixing in a super hydrophobic solution? or spraying/dipping your bio plastic with a super hydrophobic spray. I know there are a lot of products on the market and new ones coming all the time. Not sure about cost though..

author

This is a very simple recipe, there are many others that will bind much like a glue, and stay less flexible after a period of setting! I'm not sure how feasible it would be for a harness, but there are definitely ways of making it waterproof. If you find a way, please update me, I'd love to see what you come up with.

I'm glad you enjoyed it, thanks for reading! I am hoping to work for a more environmentally friendly company as a career.

author
Starsword7 (author)2015-04-30

Wow!

This is amazing, and so simple too.

Is there a way to make waterproof bio-plastic?

author
kkiecke (author)2015-04-24

You have really sparked the imagination of some folks. You definitely sparked mine! It seems our kids keep getting smarter and smarter (as a tv show has made clear!) so, this really would make a great school science experiment. You never know what wiz kid will pick up on it to create a new future for plastic. Wouldn't that be nice! I'm sure going to play around with this to see what I can come up with on my own.

Oh and it really is a shame that there always seems to be "those" types of people who feel they're smarter than everyone else and feel it is perfectly fine and appropriate to tear others thoughts and ideas down! Seen any app reviews lately? Good grief! What has happened to us as a society?

Apologies for the social rant on your instructable! Thank you for posting this. It sounds like a lot of fun to play around with!

author
jordan.stark.505 (author)kkiecke2015-04-25

Rant away! I totally agree. I always welcome criticism, as I am far from knowing everything. I appreciate all of the feedback I have gotten based on this project!

Right now, I am still in college, but I hope to make a career out of the subject of bio-plastics one day, whether it is by improving composting procedures or creating an all new material to be used for packaging. It's great to see I am not the only one passionate about creating a better future for my children!

author
kkiecke (author)jordan.stark.5052015-04-26

I sure wish there were a way to get this out to middle school science teachers!

author
smalcolm (author)2015-04-24

To what use could this be put?

author
gregfisk25 (author)2015-04-21

Hi,

Is there anything you can use this for, or is it just a demo?

author

This particular recipe is mostly a demo, showing how you can make a simple plastic from household ingredients. There are some larger companies that have packaging products used the same as traditional (petroleum) plastics, but I do not have the equipment or the expertise to make corn plastics at that skill. I did a project on sustainable plastics for one of my classes at university, and I thought a little experiment would be a fun addition to my final presentation.

author
callhow (author)2015-04-19

Looks like an awesome idea. I'm guessing the next idea(s) to come forth would

be an ingredient to make it hard enough to be fabrication. Cut-drill-etc.

- AHNauss

author
jordan.stark.505 (author)callhow2015-04-20

Yes! This technology is not new. There are several companies that make plastic using corn, rice, potatoes, plant matter, and even one that uses the protein from chicken feathers! Basically all of the same things can be done with corn as petroleum, but there are issues with cost, sustainability, and the fact that there aren't a lot of facilities equipped to handle vegetable based plastics like these, so they end up at a recycling facility. At that facility, they have to sort the plastics before they can be processed, but there are few composting facilities that can handle large volumes. It's a big mess really, the whole system will need to change in a big way before those products will be used on a larger scale.

author

isn't there a way to use milk proteins? I thought they were hard but somewhat fragile. Can't remember where I have seen it done however.

They use corn to make a wool roving/silk substitute. It is super soft. Difficult to felt and I don't know how to spin yarn so I do not know how easy it is to use to spin.

author

What you are looking for is called "Galalith" or "Erinoid".
Lots of recipes can be found around the Net, the original would use formaldehyde (like in the industrial process), which you (really) want to replace with a weak acid like vinegar or lemon juice (I prefer the latter).
Note it's completely fireproof, but you can make that even better by adding some baking soda (it's gonna make CO2 bubbles), but will then take months to dry to the core (I even tried microwave oven!). This is my very own version of "Starlite" (see http://en.wikipedia.org/wiki/Starlite), I must say it works very well to reproduce the eggs-under-blowtorch experiment ;-) but I didn't try the laser-blow yet (this was my 10-billion-pounds comment, a bit better than 2 cents).

Note that "corn starch" is also known as "corn flour" and "baking soda" is actually "sodium bicarbonate", corns starch burns pretty easily. Avoid salt, it makes sparkles.

author
bpark1000 (author)2015-04-21

To get ammonium acetate, mix vinegar and ammonia. I would add a little excess vinegar (vinegar odor versus ammonia odor).

author
gadsden (author)2015-04-21

Good ideas! Another bio oil that is nontoxic and fast drying is tung oil.
It is used for wooden bowls, utensils, etc. (as well as furniture...).
Though I haven't conducted research comparing their drying speeds I do know it is faster drying than the veg oils with which I'm familiar, which stay gummy for a long time.

author
gadsden (author)2015-04-21

For water resistance try painting your bioplastic object with beaten egg and then heating it. When egg is cooked, or just heated in the sun, its protein is very durable and water resistant. Think of how hard it is to clean egg off your car or house when someone has egged them. And remember that back in the day master artists mixed egg with pigment to make paint - and their paintings are still around, hundreds of years later.

author
farticus (author)gadsden2015-04-21

Just the yolk http://en.wikipedia.org/wiki/Tempera

Or milk http://en.wikipedia.org/wiki/Casein_paint

And or a final coat of a drying vegetable oil, such as linseed, http://en.wikipedia.org/wiki/Drying_oil

author
jordan.stark.505 (author)gadsden2015-04-21

That is brilliant! Thanks for the suggestion, I definitely would not have thought of that.

author
The Rambler (author)2015-04-21

This is really awesome and definitely makes me want to try it.

author
M4n0v3y (author)2015-04-21

Hi!

congratulations! It's nice!

Now I am going to try the real application for shopping bag at supermarket.

author
dmadam (author)2015-04-21

If I a bowl as a form would it stick to it and not come off?

author
jordan.stark.505 (author)dmadam2015-04-21

it is fairly flexible, so it should come off easily, if you are worried about sticking, I would form some aluminum foil over the bowl, and smooth it as much as possible!

author
NathanSellers (author)2015-04-19

This could be cool. Is there a coating to put on it that would prevent it from breaking down in water?

author

Absolutely! I'm not sure about a coating that can be created with simple kitchen materials. Check out NatureWorks, their company has plastics that are used with liquids (disposable cups, etc.). Not breaking down in water becomes an issue with disposal though, since it is much more difficult to break a product down it requires prolonged periods of heat and processing.

author
seamster (author)2015-04-19

Fascinating idea! I'm quite intrigued by this. Any photos of anything you've made with this?

How durable is it? . . . For instance, is it easily breakable by hand?

author

This particular type is sort of squishy, even after drying. It is mostly an idea of what can be done with these simple ingredients. There are a few companies in the US (mainly NatureWorks) that make corn based plastics on a large scale for packaging materials. With less glycerin, the simple plastic would be harder and less flexible, thus easier to form specific shapes, like bowls and the like.

author
vonronge (author)2015-04-20

Great for kids!

author
Nelly43 (author)2015-04-19

Very well written. I commend you on the thoroughness and volume of information.

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