DIY Bio-plastics

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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!

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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!

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    39 Discussions

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    banowaaati

    Question 20 days ago on Introduction

    I'm a bit confused between glycerin and glycerol.. Some articles said to use glycerol..
    Which one we have to use?

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    Hiya898

    Question 1 year ago on Step 2

    can you please share the measuremens of the ingredients?

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    CheckYourGages

    4 years ago on Step 6

    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?

    2 replies

    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

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    DevLochanjordan.stark.505

    Reply 2 years ago

    Jordan,

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

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    UtopianKing

    2 years ago

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

    Will post results, but it will take time.

    #Dear

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    Sammy A

    2 years ago

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

    1 reply
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    UtopianKingSammy A

    Reply 2 years ago

    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)

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    Na101

    3 years ago

    epicnessness

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    miked2001

    4 years ago on Introduction

    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

    2 replies
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    bar.spartanmiked2001

    Reply 4 years ago

    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..

    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.

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    Starsword7

    4 years ago on Introduction

    Wow!

    This is amazing, and so simple too.

    Is there a way to make waterproof bio-plastic?

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    kkiecke

    4 years ago on Introduction

    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!

    2 replies

    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!

    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.