ask our experts about
your home-made bioplastic project!

Giovanni writes in to ask:

I have studied organic chemics, I never thought about bio-plastics. Now that I do, after finding occasionally your site, I wonder if they may be used to create glues. It would be wonderful if I could just mix something together and refill my glue bottle once and then, rather than buying all the time small amounts and hoping they will not dry out too quickly.

As a hobby I construct model naval vessels and normally I use a glue called "Vinavil", which is somewhat bio, I guess, but not too much. The quality of this glue is however low (except for the strength) and anything else may be easily better. After reading most of the receipes and comments, I believe that adding more plasticizer will create a jelly-like plastic which eventually hardens. As I know from anorganic chemics, thermoplast is normally a very good glue, but it is difficult and somewhat dangerous to apply (heat). And, when it is dry, ususally it hasn't really penetrated and pieces break quickly apart.

The jelly-glue makes me think that the remains of water will soak into the wood and thus penetrate the glue into. Now, since it is only an idea ... do you think it may work? Or does the jelly-plastic never harden? I would like just to hear your opinion, before I start to transform my kitchen (and office) into a semi-professional chemistry laboratory with all the people staring at me

Thanks for writing in with your question, and I'm glad that you've been inspired to work with bioplastics.

Unfortunately, I don't think that bioplastic will be very effective as an adhesive.  Anything that you applied to other surfaces (the surfaces that you want to stick together) would probably not penetrate very deep, and have the same problem as thermoplastics.  Also, if you add too much plasticizer you have a good chance that it will stay "gooey" forever, rather than hardening.

You can always feel free to experiment, of course!  I would love to hear the results, if you do.  But my initial reaction is that bioplastics won't have the properties that you need for an effective adhesive.

Young Ju Do wrote in with a question:

Dear Green Plastics,
Do you have any data or researches about that how long bioplastic takes to be degraded in different environments/conditions?
I made bio plastic then put in compost bin. It degraded. But I also want to know different cases. Also want to know how long it will last in air.

Thank you for your great question! As I am sure you know, different types of bioplastic biodegrade at different rates, depending on what polymer they use, what additives they include in the formulation, and how it is processed.  Additionally, of course, the rate of biodegradation will depend on details of the environment as well: the temperature, exposure to moisture and microorganisms, the amount of initial physical degradation ("breaking apart") of the product, and so on, all play a role in determining the final timeline.

Unfortunately, to the best of my knowledge there is no comprehensive comparative study or meta-study out there: something that compares the rate of decomposition of different bioplastics in one Scenario A, then compares the rate of decomposition of those same bioplastic materials in another Scenatio B, and so on.  This kind of comparison grid would be very interesting, and very valuable. But I do not believe it exists.

To of our readers: If you know of such a study or report that provides such a comparison, please let us know so that we can post it for people here.

The closest thing available that I know about is the website bpiworld.org. You should take a look at that excellent website.  They have a list of products the have passed the ASTM standard tests for compostability and biodegradability; i.e., whether the products are compostable in municipal and industrial composting sites (ASTM D6400 and ASTM D6868).

The ASTM standards, like the international standards, simply answer the question: will the material degrade to the required extent in the specified period of time. It's a simple yes or no (pass or fail). The exact rates of degradation need not be displayed as long as they pass.  If they pass, manufacturers can then display a logo to show they passed.

Ploy Chidapa wrote in with a question and a video:

Dear Green Plastics,
Hello. I try to make bioplastic for my science project in my school by 16g. of cassava starch, 15 ml. of glycerin, 15 ml. of vinegar and 100 ml. of water.
but it's not flexible, easy to tear and a lot of bubble like this video http://youtu.be/HO1yjGghhoI.
Please give me some suggestion. I am waiting for your answer. Thank you

Thank you for your great question, and the video.  I can clearly see the problem that you are talking about: your end result is pretty stiff and inflexible, tears easily, and has a lot of bubbles and waves in it.

The easiest problem to solve will be the texture and bubbles.  The mixture can't be too thick when it's being made and heated. If it's too thick, air bubbles will get trapped in the mixture when it's heated and won't be able to get out. Try adding more water. It will take longer to dry, of course, but that will help to get rid of the bubbles. You should also make sure that it's heated long enough for the starch to get "dissolved" completely, and you should be able to skim any "foam" that might form during heating from the top.  The overall idea is to make sure that you take your time during the "cooking" phase, and make sure there are no lumps in the mixture before you pour it into whatever form it will be drying into.

The problem of the plastic being weak and inflexible may be more difficult to solve.  The most obvious way to increase the flexibility of a bioplastic is to increase the amount of glycerol (the plasticizer).  This will make the end result more bendable, but it will also make the plastic weaker. So this might aggravate the problem of the plastic tearing easily.

One of the reasons for this is just inherent in starch-only plastic. Starch, by itself, generally does not make a very strong film. I don't know the parameters of the project, but if you could add some gelatin to the mixture to provide a stronger polymer, that would help.

Either way, good luck with your next batch, and happy experimenting!

Recently Nerissa Haak wrote to us:

Thank you for your letter, Nerissa!

Some bioplastics are microwavable and others aren't. It will depend on the composition and how it was processed.

Unfortunately, if the bioplastic contains glycerol, as with all of the bioplastics that are "home made" that we talk about on the website, the plastic will blister and discolor if microwaved (for example, for one minute on high). So none of the home-made bioplastic projects that we describe on this site produce a result that is microwaveable.

However, there are a number of commercially-produced bioplastics that are microwaveable. Expanded starch foam (starch packaging peanuts, for example) is rather stable in the microwave. One commercial product that is currently on the market is the clam-shell fast-food tray, by Earthshell. This product is being marketed for use by fast-food burger restaurants, and can be microwaved. The Earthshell material is starch-based, but it goes through a complicated production process that isn't something that you can do as a home project.

There is likely going to be more research done in the area and more bioplastic packaging options will become available, at reasonable cost.

Hope that helps, and good luck with your project!

Recently Ankur Sharma wrote to us:

Hello, I really appreciate your effort to make these videos and information
But i was thinking of making corn plastic utensils (glass, plate, knife etc.).
I would really want some tips from u. do i need molds. If i put the materials in a mold after cooking to let it dry, is it going to work. will i have plastic in shape of the mold. what should be the proportion of glycerin:vinegar if i want my plastic to be hard and not very flexible.
Also can i use the process which is used in the youtube video - How to make bioplastic(extended version)
or do i need more materials
i am awaiting a reply eagerly.
Thanks and again really appreciative work. Well done!

Thank you for your letter, Ankur!

First, I want to start out talking about some basic definitions.

When you hear about commercially-produced "corn plastic" utensils and cups, generally you are hearing about bioplastic that is based on the polylactic acid (PLA) polymer.  Polylactic acid is polymer that is created by polymerizing lactic acid molecules. In simple English, PLA is a long chain molecule that is created by linking (polymerizing) a large number of lactic acid molecules together.  The lactic acid is created by fermenting starches and sugars, and most commonly corn starch is the source for these commercial products.  Thus, these products are called "corn plastic" or "corn starch plastic".

The sequence of events in the commercial creation of this kind of plastic is therefore as follows:

• Complex starch from potatoes, corn, fruits, or other starchy plants is broken down into sugars using enzymes
• The sugars are fermented into lactic acid using bacteria.
• The lactic acid is purified
• The pure lactic acid is polymerized; in other words, the individual lactic acid molecules are chained together to form polymer molecules that will form the basis of the bioplastic.
• The poly-lactic acid (PLA) is refined, combined with other ingredients such as plasticizers and additives to produce a bioplastic resin, or bulk plastic material.
• Finally, the bioplastic resin is processed so that it can be molded into the shapes of the final plastic products.

(Image to the right is from Toyota Corporation.)

All of this chemical processing is far beyond what you can achieve in your own home, although you can read and learn a great deal about this process on the web. For some of the basic chemistry of PLA polymerization, I would even recommend Wikipedia: Polylactic Acid.

So what can you make in your own home? You can make plastic from starch in your own home.  However, the polymer basis for the plastic will not be PLA, it will be the starch itself.

Yes! Starch is a polymer molecule. Specifically, it is a type of polysaccharide.  Whereas PLA is composed of a long chain of Lactic Acid molecules, starch is composed of a long chain of glucose molecules.   When you are making "starch plastic" using the instructions that we provide on this site, or in Brandon's video, you are using the actual starch molecule as the polymer chain in the material.

Q: If starch is already a polymer, why do commercial companies go through all of that trouble (the steps above) to convert starch to PLA? Why not just make starch utensils?

The problem is the starch, by itself, does not make a very sturdy plastic.  You can make thin flexible films that can be very useful, but it is generally too flexible and too weak to make solid objects like cups or utensils.  For the most part, starch plastic is good for making wrapping material, packaging, and coating films.  This is why "corn plastic utensils" means "PLA utensils" and not "starch utensils"... even though the PLA originally is made from starch to begin with!

Uh oh.  So where does that leave you?

Unfortunately, it means that you may have to alter your plans slightly if you want to make your own bioplastic utensils.  That is, you probably don't want to start using starch as your biopolymer.

Fortunately, however,there are other biopolymers that you can use in order to make stronger, harder bioplastics in your own home.  My recommendation would be to start with gelatin as your polymer, and to follow our ingredients and instructions in these articles:

Home-made bioplastics sword (gelatin biopolymer)
Bioplastic by Da Vinci (gelatin biopolymer)

Both of these articles provide specific formulations for hard, inflexible plastic objects, which should be good for your goal of making utensils. In either case, you will want to make sure that you make the mold first, and that you leave enough time for the plastic material to try once you have poured it into the mold.

If you are not satisfied with your results using gelatin as a polymer, you can also use agar. The recipe and instructions are here:

How to: make algae bioplastic (agar biopolymer)

This is a very popular formulation that produces very good results, and by manipulating the amount of sorbitol that you include you can make it harder or more flexible, depending on your needs.

Good luck with your project, and happy experimenting!

Remember, if you have successfully made bioplastics using our recipes or suggestions please send photos or video to This e-mail address is being protected from spambots. You need JavaScript enabled to view it This e-mail address is being protected from spambots. You need JavaScript enabled to view it This e-mail address is being protected from spambots. You need JavaScript enabled to view it and we will post it on the website and help give you some publicity!

zia ur rehman wrote in with this question:

I am a student of biotechnology in University of Peshawar,
Pakistan. Now a days i am working on a project to make bioplastic
(PLA polylactic acid specially) from starch (CORN/ Sugarcane). I
wants to ask you the exact procedure and materials I require. I will
also add some of the ingredients to increase its stiffness, and also
will work to make it better.

Zia, thank you so much for your email! I think it's great that you are going to work with bioplastics for your school project. Projects that involve making your own bioplastic are a great way to learn, first hand, about how different materials and of ingredients affect the properties of a plastic. As you will learn, including different ratios of polymer and plasticizer, as well as other additives, can vastly alter when strength, flexibility, stiffness, and other properties of the end result.

My first suggestion is that you should buy, if you are able, the book Green Plastics: An Introduction to the New Science of Biodegradable Plastics by E.S. Stevens. This book will get you started with a wide variety of recipes and step-by-step instructions on making bioplastics with different properties, ranging from hard inflexible plastics to thin flexible sheets and laminates. In addition, the book carefully explains the theory behind bioplastics, with in-depth discussions of chemistry concepts as well as environmental concepts related to biodegradability and renewability.  This book can be ordered online from Princeton University Press or from Amazon.com; however, I honestly do not know if it can be purchased from and shipped to Pakistan.

In case you cannot buy the book online from where you are located, we have a number of articles and references for you on this website.

The first reference that I would recommend is Brandon's Video.  He talks through the actual process that he uses.  If you have difficulty understanding exactly what he is saying, there is a transcript available on that page if you scroll down below the video itself.

Some people have had difficulty with his recipe, however, so I will provide you with two other pure starch-based bioplastic recipes.  I would still encourage you to look at his video so that you can see the procedure to use, in action.

Recipe 1: starch + salt + glycerol

• 3.0 grams (1 tsp) starch
• 45 mg salt
• 160 ml (2/3 cup) of 1% glycerol solution

Recipe 2: starch + salt + glycerol + sorbitol

• 3.0 grams (1 tsp) starch
• 45 mg salt
• 120 ml (1/2 cup) of 1% glycerol solution
• 0.75 grams (1/4 tsp) sorbitol
• 40 ml (1/6 cup) water

How do I make a 1% glycerol solution?

Sometimes when you buy glycerol, you can buy it already in a 1% solution. When you do purchase your glycerol, make sure you read exactly what you have so that you know whether you have a diluted solution or pure glycerol. If you have purchased pure, undiluted glycerol, you can create a 1% solution by mixing up a solution that has 10 ml of glycerol for every liter of water. This will give you a solution that is "1% by volume."

How do I get exactly 45 mg of salt in the mixture?

You can use simple table salt (sodium chloride) for this. If you put 9 grams of salt in a liter of water, then 5 ml of the solution will contain 45 milligrams of salt.  You can then use this 5 ml of salt solution added to regular water in order to mix up your glycerol solution, according to the instructions above.

(If you are curious what the salt is for, chemically-speaking, we talk about it in this article: Why water and vinegar?)

What do I do when I have all of the ingredients?

Mix all of the ingredients together in the amounts above, and stir.  Keep mixing until there are no clumps, and heat the mixture to 95 C or to when it starts to froth (whichever comes first). Stir the mixture while you are heating it, and once it is at the right temperature (or starts to froth), remove the heat and keep stirring.  Scoop out excess froth with a spoon, and make sure there are no clumps.  The mixture will start to froth a great deal if it is overheated, so be sure to remove it from the heat and stir, scooping out excess froth if necessary.

You will want to carefully pour the mixture directly into the mold that you are using. How long it will take to dry will depend on the temperature and humidity in the room, and how thick the final product is. It may take several days, so be patient! Sometimes people find that it helps to blow it with a blow-dryer for a period of time.  If your first batch turns out too sticky or slimy, you can try it again with slightly less plasticizer (glycerol).

These two recipes are for pure starch-based plastics.  If you are interested in looking at alternatives that use other polymers, such as agar or gelatin, there are a number of articles on this website with recipes for non-starch bioplastics, including:

• How to: make algae bioplastic (agar biopolymer)
• Vegan Bioplastic (agar biopolymer)
• Home-made bioplastics sword (gelatin biopolymer)
• Bioplastic by Da Vinci (gelatin biopolymer)

Starch does not produce a very strong bioplastic, and it is not very good for making hard plastic objects.  If you want to try to make the starch plastic stronger or harder, I would recommend that you try blending the starch polymer with one of these other polymers.  Remember, the recipes that we give you here are the starting point, not the finishing point! From here, try changing the ingredients and proportions and see what happens!

Good luck with your project, and happy experimenting!

Remember, if you have successfully made bioplastics using our recipes or suggestions please send photos or video to This e-mail address is being protected from spambots. You need JavaScript enabled to view it This e-mail address is being protected from spambots. You need JavaScript enabled to view it and we will post it on the website and help give you some publicity!

Paula wrote in with this question:

we're making bioplastic using pectin extracted from fruit peels. but our product just looks like jelly. i learned from watching the video that amylopectin is not enough. can you please suggest any additive?

Paula, I think that bioplastic made from fruit peels is a fantastic idea for a home project! On this website, we have had discussions and recipes for home-made plastic made from everything from algae to gelatin, but we haven't actually talked about fruit peels yet.  I've never actually tried using pectin (the polymer from fruit peels), but it should produce a good product. Plus, it follows a general topic of interest that is popular these days, and that is: how can we actually produce plastic from materials that otherwise would be considered waste?  (I'm excited to see what you can come up with.

However, as you experiment, there are a few things that you need to keep in mind.  One is the most basic equation that describes all plastic:

plastic = polymer + plasticizer + additives

Sometimes you can do without additives, but if a material doesn't contain at least a polymer and a plasticizer, then it's simply not plastic.

Amylopectin is a polymer that should be able to produce a good bioplastic. Unfortunately, I cannot tell from your question what you are using as a plasticizer, or if you are using one at all. You refer to "the video", and if you are referring to our home-made bioplastic video online, then you may have tried using glycerin as a plasticizer, since that is the plasticizer that Brandon uses in his demonstration.  If you have not tried this, and your recipe did not have any plasticizer, then it will not produce plastic.  The substance that you get will gradually dry over time, passing through a gel stage (much like jello) and eventually hardening into a brittle sheet that will break up into small pieces.

On the other hand, if you tried adding glycerin (or some other plasticizer) and added too much, then the final product will remain sticky and weak and may have a consistency much like jelly, like you described.  If it remains like this after a number of days, the most likely cause is too much plasticizer.  This is actually a very common mistake that people make, and unfortunately it is because of people mis-reading the way recipes for bioplastic are often written.  For example, in another post we have provided a recipe for a agar-and-glycerin plastic that looks like this:

3.0 g (1 tsp) agar
240 ml (1 cup) of 1% glycerol solution
180 ml (3/4 cup) water

This means that you have to use 240 ml of a solution that contains one part glycerin for every 99 parts water.  That is actually a very, very diluted form of glycerin. If you do not measure this accurately, so that you have a glycerin solution that is too strong, then you will end up with jelly instead of plastic.

Generally speaking, when you are casting biopolymer films, this is what should happen.  You will first see a thickening of the mixture. When you pour the mixture it will pass through a gel stage (much like Jello). After that you have to let the gel dry, a process that may take several days (depending on the humidity). After the gel dries completely it will be a flexible film. Too much plasticizer and the film will be sticky and weak; too little plasticizer and the film will be very brittle, but tough. You have to find the right amount of plasticizer.  And often this is something that you can only figure out by trying different things and experimenting... especially when you are experimenting with a new polymer!

Best luck with your bioplastic project!

Remember, if you have successfully made bioplastics using our recipes or suggestions please send photos or video to This e-mail address is being protected from spambots. You need JavaScript enabled to view it and we will post it on the website and help give you some publicity!

Akhilesh has written in with this question:

Hello everyone
I have prepared starch-based bio-plastic at home.I want to increase its tensile strength.How can that be done?Please help me

Akhilesh, I have to tell you that you have hit on one of the top research questions now going on in the area of bioplastics. Unfortunately, that means that there is no simple answer for your home bioplastic project, although you do have a few options.

First, I want to make sure that we understand what you are really asking for.  The tensile strength of a strip of plastic is technically the force it can bear, under tension, per unit cross sectional area of the film, without breaking.  The "cross sectional area" is measured as the width times the thickness. If all you want to do is increase the strength of your piece of plastic, the simplest thing to do is make it thicker:  this would allow the piece of plastic to bear a greater load under tension without breaking.  However, it would not increase the tensile strength, which is a technical property of a plastic that doesn't change with the size and shape of the piece of plastic you are considering.

Tensile strength is a very important property in the plastics industry. It determines what types of applications the plastic can be used for, and in many cases is even highly regulated in certain industries.  For example, all plastics used in automobiles must meet specifications to ensure that the particular part performs satisfactorily, and these include specific values that must be met for tensile strength, as well as other properties like impact strength and flexural modulus.  As a result, coming up with a bioplastic that will have satisfactory tensile strength for various industrial applications is absolutely one of the top business questions on the minds of bioplastics producers.

So what about home-made starch plastic?

When you are working on a home or school project, the easiest way to get a bioplastic with a better tensile strength is to use a different polymer. Starch cast films are simply not that strong, so in order to make them stronger you have to change the chemical composition.  Instead of using starch, you could use agar, which is the biopolymer component found in algae plastic or bioplastic made from seaweed.  Agar films have a much higher tensile strength than starch films, so the more agar in the film, the larger the tensile strength. You can also combine starch with agar to make plastics with intermediate tensile strengths.  By making starch-agar films with increasing amounts to agar, you can get increasing tensile strength from your plastic.  We have an earlier article, HOW TO make algae bioplastic, that describes the specific ingredients and measurements for both pure agar bioplastic and starch-agar blends, as well as information about buying agar.

Larger companies, of course, have other more high-tech options that they can pursue for increasing tensile strength in bioplastics.  This is part of the reason that some companies specialize in producing blends that are part bioplastic and part traditional plastic: they claim that the end result is still more "environmentally friendly" because of the bioplastic element, but the traditinal plastic mixed in can make it stronger or more flexible.  Of course, the end result is not biodegradable, so how "environmentally friendly" this option is may be debatable.

There is also some very current research going on with using cellulose particles (either cellulose fibers or nanoparticles) added to bioplastics to add strength. For example, there is work being done to add cellulose fibers to starch foams to increase the (compressive) strength of starch packaging peanuts. The cellulose does increase the strength but it also increases the density of the peanuts, so there's a trade-off.  However, these products are made with extrusion, which is not what you are doing with your home project.  You are making a cast film.  In homemade cast films, the addition of cellulose may not work.  Cellulose is completely insoluble in water so the cellulose may not interact with the starch enough to affect the properties; the cellulose might even prevent the formation of the films. However, this is a very promising line of inquiry in the industrial manufacture of bioplastics, because if the plastic can be made stronger using cellulose, the end result will still be 100% biodegradable and made from renewable resources.

Best luck with your bioplastic project!

Remember, if you have successfully made bioplastics using our recipes or suggestions please send photos or video to This e-mail address is being protected from spambots. You need JavaScript enabled to view it and we will post it on the website and help give you some publicity!

Here is an example of one of the most common types of emails that we receive here at Green Plastics:

I am a student and just beginning to learn about chemistry. Is there a good simple website that I can go to find out the basics about bioplastics? Every site that I find online either doesn't have any chemistry information at all, or it's way too technical or advanced.  Is there anything out there for people who want to learn about what bioplastics are really about, but aren't "industry insiders" already?

This is a great question, and in fact this is exactly what we are all about: being an information resource for students and people who are just beginning to learn about the science of bioplastics.

If you are looking online, my first recommendation would be the website Green Plastics: Definitions, concepts and explanations about bioplastics. This is set up basically like Wikipedia, with a lot of introductory articles about basic concepts, defining (for example) things like what plastics are, what a biopolymer is, and how bioplastics are different from regular plastics, and so on.  It also has some good discussions of background terms that are important to understand like biodegradation and renewable resource.  The website is deliberately written to give you some science, but to not be overwhelming for beginners.

If you want a little more, and are willing to go beyond the internet, I would recommend the book, Green Plastics: An Introduction to the New Science of Biodegradable Plastics written by E. S. Stevens. It has some chemical formulas, some recipes for making bioplastics at home, and a lot of very basic chemistry information so that you can learn about things like degradability, composting, and the basic chemical make-up of bioplastics.

Finally, of course it would be wrong of me not to recommend this site! Browse through our discussion section, and you will see a lot of basic questions that we have answered over the years. A lot of them are written exactly at the level for introductory students (highschool and college) who want to learn more about the chemistry of bioplastics, including things like what is the chemical formula for bioplastic and what is the role of vinegar in making bioplastic?

And of course, if you don't see your question answered on here already, don't be too shy to ask! That's what we're here for.

Good luck in your research!

Today I read an article called Cheese byproducts and bioplastic film packaging about a new packaging material that is biodegradable and made from whey protein. I want to commend this effort, and I think it is a fantastic advance in bioplastics and the materials industry. The fact that it is water-proof enough to be used in food containers, but that the material breaks down in water with the simple addition of enzymes, is especially promising. This material deserves serious attention and kudos.

But...There is something wrong with the article.

There is a sentence, right at the center of it, that is misleading (at best) or incorrect (at worst).

As a student of bioplastics, and if you have been reading this website, you should be able to spot it. Can you?

The sentence in question is this: "This new plastic is made using whey protein, which means it is biodegradable."

.

In an earlier article, Shades of Green, we talked about a product called "green polypropylene" which is made from sugar cane, but after the manufacturing process is complete the final polymer molecule is identical to traditional plastics in every way.  As a result, it is not biodegradable.  It is made from sugar cane, but because of the way that it is processed, the way it reacts in the environment is just as "unnatural" as traditional plastics.

By contrast, one of our featured articles, What's in the word Biodegradable?,talked about a technology used by ENSO bottles: an additive that can be added to traditional plastics to make them biodegradable. The plastic used by ENSO bottles is biodegradable, but is not made from renewable resources.  It is, in some ways, the opposite of "green polypropylene": non-renewable resources, but it does biodegrade.

This distinction between degradability and renewability is important: these are two components of being "green" that are completely independent of one another. And yet a lot of advertisers, promoters, and people in the media would like us to believe that because a product is one, it therefore must be the other.  Or they will simply call it "bioplastic" because it is biodegradable, and keep hush-hush and let you assume that it is made from renewable resources whether it is or not. (Or they may do the reverse.)

In the case of the cheesy bi-product plastic described in the main article, it is honestly both: it is biodegradable, and it is made from renewable resources.  But by leaving in the cheesy claim "...is it made from whey protein, which means it's biodegradable" they are just re-enforcing this mistaken belief, and making it easier for other groups to mislead consumers in the future.

Recently we have received a number of comments asking us how people can make their own home-made bioplastics that are waterproof (or at least, water-resistant).

Everyone has seen that there are waterproof biodegradable products out in the world. There are bioplastic coffee cups, there are bioplastic bowls, and there are bioplastic soup spoons.  There are even bioplastic wrappers that (one imagines) must be at least a little water resistant to work properly. So you think to yourself: "How can I do this at home?"

Unfortunately, although it is not impossible, the answer is not as easy as you might think.

Let's start by looking at the basic chemical properties of bioplastic, and why the question of waterproofing is difficult.  Most of the bioplastics that you can make at home, like the recipes described in the book Green Plastics: An Introduction to the New Science of Biodegradable Plastics, use starch, gelatin and agar as their main polymer bases.  We've talked about these recipes a lot on this website. ("Agar," remember, is the technical name for the polymer found in algae plastic.) These biopolymers are hydrophilic, meaning that they interact strongly with water; on their own, and when made into plastic, they are not water resistant.

Some biopolymers are intrinsically more water-resistant, and the most well-known example of this is polylactic acid (PLA).  This material is a polyester, is made by the fermentation of sugar feedstocks to produce lactic acid, followed by the polymerization of lactic acid into PLA.This is the type of plastic that is found in most bowls and cutlery that are biodegradable, often referred to as "corn cutlery" because the sugars that they use to create the PLA are taken from corn.  Natureworks LLC is a major manufacturer of PLA plastic, and has used it to create not only cups and spoons, but water-proof fibers for clothing, rugs, and other cloth coverings.

Polyhydroxyalkanoates (PHA's) are another naturally produced material, created by microorganisms. The microorganisms are fed with sugar feedstocks, and the PHA is extracted and purified.  Both PLA and PHA's are used to produce biodegradable water-proof bottles, bowls, eating utensils, and dishes. However, both materials are relatively expensive, so it is also common to find bioplastic products that blend PLA and PHA's with starch. The PLA or PHA improves water resistance, while the starch lowers the cost. PHA's have also been used to as a coating over pure starch bioplastic foam cups and trays.  The coating makes the product more water resistant, while still having the majority of the product made from the (cheaper) starch plastic.

Large manufacturing companies use other strategies, as well.  With specialized processes and machinery they can chemically modify even a starch biopolymer to make it more water resistant. For example, starch-based packaging "peanuts" are made water-resistant by acetylating the starch: the hydroxyl (OH) groups on the starch are chemically converted to acetyl (OCOCH₃) groups. This process produces packing peanuts that have a higher water resistance, but are still biodegradable. Commercial manufacturers also sometimes blend their polymers: for example, a combination of starch with polycaprolactone has used to make sturdy garbage bags.

However, Natureworks LLC and other large-scale industrial companies have access to processing and machinery that you do not have.  You will not be able to manufacture PLA or PHA's in your kitchen, and you will not be able to acetylate your starch polymers.  So what can you do?

One strategy used by the "big companies" that you can mimic is using the idea of a coating.  Commercial products are often made water resistant with very simple coatings, such as waxes, oils, and even shellac. For example, cellophane, still sometimes used for candy wrappers, cigarette packages, and cigar wrappers, has a base cellulose sheet that absorbs water, but is made moisture proof with a very thin wax coating. Ordinary brown kraft paper can be made water resistant with a thin wax coating and used as an agricultural ground cover.  Water-proofing coatings can also be applied through lamination, in which two or more layers of material are bonded together. For example, a starch sheet can be laminated with a water resistant coating of polycaprolactone, a biodegradable polymer made from nonrenewable petroleum-based feedstocks. Unfortunately, this would make the end product biodegradable but less "green" because it is made from non-renewable resources.

So, making water-proof home project bioplastics will require some experimentation. But whether you want to water-proof a solid object, like a gelatin viscose bowl, or a flexible sheet product, the best starting point would be to figure out how to apply a thin water-proof coating onto the surface. If you are working with a porous thin sheet, you may be able to use oil. Otherwise, you may want to experiment with wax or a wax-like substance.  If you find even better ideas for ways to coat your bioplastic projects... make sure to leave us a comment here and let us know.

Happy experimenting!

A couple of students have recently been trying to understand why certain ingredients are used in the creation of bioplastic.

Eliza Sham asks:

I am interested with your recipe to make bioplastic. What is the use of the water in adding to the starch to make bioplastic?

Please answer me.

Thanks a lot!:-)

Hi,
I want to ask what is the principle of the bioplastic and the use of water and vinegar
Thank you !

I think we can answer both of these questions at the same time!

Water: Water is used as a solvent to get the biopolymer (starch) into solution. When the solution is heated, the water helps the starch molecules to become disrupted and disordered (denatured). When dried, the disordered polymer chains become entangled and a neat film is formed. The process is called film-casting.

Vinegar: Starch dissolves better if a small amount of ions (electrically charged particles) are present in the mixture; the polymer molecules become disordered more easily, and the resulting cast films are somewhat improved. These added ions interact with both the starch and the small amounts of other polymers (lipoproteins) that are present in commercial starch. One way to add ions into the mixture is to use ammonium acetate. Ammonium acetate works very well in this respect because it forms ammonium ions and acetate ions in solution. However, ammonium acetate is not readily available. Vinegar is a practical alternative that you can use when making your own bioplastic. Vinegar contains acetic acid which forms hydrogen ions and acetate ions, and (importantly) it is readily available. This is why adding a little bit of vinegar is recommended specifically when making home-made bioplastic films from starch.

If you can't (or don't want to) use vinegar, ordinary table salt (sodium chloride) is a reasonable substitute; it forms sodium ions and cloride ions. Whatever is added, the ions that are formed in solution help to dissolve the starch and to denature the starch when the mixture is heated, so that when the mixture is dried, somewhat better films are formed.

Hope this helps! Happy experimenting.

In a comment to our article Home-made bioplastic sword!, Larry asks this:

I have been experimenting with bioplastic. In this article are you saying the only way to achieve a hard bioplastic is to use Gelatin. I don't want to use an starch from animal hooves. Is there a recipe to get a hard plastic by using Agar, Tapioca, corn, and/or potato starch? I noticed in "Brandons Remix" video he had made a hard disk like piece but does not say the recipe. Thanks.

This is a great question! Starch is very good for certain types of bioplastic, like thin flexible films or the type of bioplastic that is now commercially used for cups and utensils.  But starch does not produce a very good plastic for hard solid objects like buttons, decorations, cup coasters, and so on.  In the Green Plastics book, there are a number of recipes for hard solid plastic objects, but most of them use gelatin as the main or secondary polymer. 

But some people don't want to use animal products or bi-products in their projects.  They want to go a step beyond bioplastic and have vegan bioplastic: biopolastic that does not involve the harm or use of animals!

How can we do it?  There is a simple answer: algae!

Yes, agar (the main compound in algae that is used as a polymer to make bioplastic) produces a pretty good hard, inflexible plastic.... as long as you use a very small amount of plasticizer.  In our earlier article on algae plastic, HOW TO: make algae bioplastic, we give several recipes along with detailed instructions on how to do it.  (Make sure you check out that article.)   However, those recipes will generally produce a thin flexible film.

The recipe for pure agar bioplastic in that article is this:

3.0 g (1 tsp) agar
240 ml (1 cup) of 1% glycerol solution
180 ml (3/4 cup) water

Mix all of the ingredients together in the amounts above, and stir.  Keep mixing until there are no clumps and it is as dispersed as it's gong to get.  Then heat the mixture to 95 C or to when it starts to froth (whichever comes first). Stir the mixture while you are heating it, and once it is at the right temperature (or starts to froth), remove the heat and keep stirring.  Scoop out excess froth with a spoon, and make sure there are no clumps.  Carefully pour the mixture into a drying pan, and make sure to spread it out to let it dry.

NOTE: The above recipe will not produce a hard, inflexible piece of plastic!  It has way too much glycerol, which is the ingredient that is the plasticizer.  Remember the general formulation for all bioplastics is Polymer + Plasticizer + Additives.  In this case, the polymer is the agar and the plasticizer is the glycerol.

So how much glycerol should you use?  It depends on exactly how hard and inflexible you want the plastic to be.  I would recommend trying a few different ratios: this is like cooking, you'll probably have to do it a few times before it comes out "right".  But start with a ratio of 1/2 cup of 1% glycerol solution to 1 tsp of agar, to begin with, and see how that turns out.  You can then decrease or increase the amount of plasticizer depending on whether you want the end result to be harder or less brittle.

So have fun experimenting!  As always, if you end up with a successful project please send in photos or video of it and we will feature it here.

SOME FINAL TIPS AND TRICKS:

• Where can I buy agar?  If you're in school, your school's chemistry lab may have it or may be able to order it for you.  If not, you can actually order it yourself: just google "buy agar" and you will get some links.  I think they actually sell it on Amazon.com now, amazingly enough.
• How long will it take to dry?  You may have to be very patient, especially with a thicker mold for a thicker final product.  It may take a day or two to dry, and it helps if you keep it in a warm, dry environment while it is drying.  If it takes longer than a week, you probably want to scrap it and try again with less water or even less plasticizer.
• Are you using the right amount of glycerol?  Please remember that the recipe calls for a 1% glycerol solution.  If you measure out 1/2 cup of pure glycerol then you will be using 100 times the recommended amount!   You can buy glycerol in a solution form, but if it is more than 1% then you need to dilute it. For example, this product advertises itself as a 50% Glycerol Solution.  You need to cut that with a lot of water (do the math!) to bring it down to 1%.

Good luck!

Hello greenplastisnet,

I know that burning plastic has some very bad outcomes and should be avoided.  I was wondering if there has been any study on what happens to the bioplastics (any of them) when they are burned.  Do they still release harmful chemicals?  If they are burned will it speed up the process of them degrading?  I am looking to design a product that will be an ecological upgrade to a current widely used item, and this product will more than likely be burned.  Thank you for any information that you do have and if not could you maybe point me to someone that I could talk to about this.
Nate

RESPONSE FROM GREEN-PLASTICS.NET:

This is a very good question, and I'm glad that you asked.

The harmful results of incinerating, or burning, plastics are mainly associated with the release into the atmosphere of dioxins and heavy metals. Dioxins are chlorine-containing organic molecules, and are very toxic.  Some polymers inherently give off chlorine when they are burnt; for example, polyvinylchloride (PVC) is especially harmful because of the high levels of dioxins released into the atmosphere.  Other plastics, like polypropylene, give off only water vapor and carbon dioxide, and so are not inherently toxic when they are burned.  However, plastics can also have additives that are toxic, such as heavy-metals. These will be released as poison into the atmosphere when the plastic is burned, even if the polymer itself does not produce dioxins.  This is the reason that commercial incinerators have such strict guidelines regulating the way that they handle the disposal of plastics.

So what about bioplastics?  True bioplastics—biodegradabe plastics made from renewable resources, such as PLA—generally contain only carbon, oxygen, and hydrogen atoms, and specifically do not contain chlorine atoms. Because they do not contain chlorine atoms, they do not produce dioxins during burning/incineration. Traditionally, bioplastics also do not have heavy-metal additives. So in general they can be safely incinerated, with no danger of releasing dioxins or heavy metals.

However, it is still important to consider the details of the particular plastic you are working with. If a plastic is made from traditional (petroleum-based) polymers and has simply been made "degradable" through the inclusion of additives, it will still produce dioxins when it is incinerated.  If a plastic that is made from renewable plant materials has been processed in a way that involves the addition of heavy metal additives, then it will release those toxins into the atmosphere when it is incinerated.  These are the questions you will have to ask when considering how to dispose of whatever type of bioplastic material you work with.

Good luck with you project!

Hello greenplastisnet,

I am looking for a ratio of ingredients for a durable plastic that Is not as flexible, but still, wont break when I hit something with it. Would I use no Glycerin at all? or do you need at least some Glycerin for it to work? I am experimenting different materials for a cheap plastic katana.

RESPONSE FROM GREEN-PLASTICS.NET:

This sounds like a fun project, but I will tell you from the outset... getting the right formulation for a katana will probably take some time, trial and error!

Your best bet will be to use a gelatin-glycerol bioplastic with a very low level of glycerol.  This produces a hard, inflexible plastic that is good for creating solid objects.  I've made buttons and coasters and ornaments before, but never anything as large as a plastic sword.  It shouldn't be too brittle, but you may want to try adjusting the amounts a little bit over several trials: remember that less glycerol means it is more brittle.

We have posted the formulation for this kind of plastic before, but in case you missed it:

Combine 3.0 grams (1/2 tsp) glycerol and 12.0 g gelatin (4 tsp) with 60 ml (1/4 cup) hot water.

Depending on how large the sword is, you may need to increase these amounts.  Just remember to keep them in the same proportions (i.e. either double everything, or quadruple everything, etc).

Mix all of the ingredients together in the amounts above, and stir.  Keep mixing until there are no clumps and it is as dispersed as it's going to get.  Then heat the mixture to 95 C or to when it starts to froth (whichever comes first). Stir the mixture while you are heating it, and once it is at the right temperature (or starts to froth), remove the heat and keep stirring.  Scoop out excess froth with a spoon, and make sure there are no clumps.

You will want to carefully pour the mixture directly into the mold that you are using to create the shape of the sword.  I assume you have already created a mold.  If not, then of course that step has to come first!

How long it takes to dry will depend on the temperature and humidity in the room, and how thick the final product is. It may take several days, and sometimes people find that it helps to blow it with a blow-dryer for a period of time.  If your first batch turns out too sticky or slimy, you can try it again with slightly less plasticizer.

One final comment: We assume that the plastic sword is meant for all fun and games and that you don't intend to do any harm with it.  But please remember: just because it's bioplastic doesn't mean it won't hurt!  You can absolutely hurt yourself or others, even if you are just playing around, by whacking eachother with plastic swords.  So please be very careful.  The plastic formulation describe here is solid and hard: you may want to wrap your final product with padding, if you intend to use it in "mock combat."

Good luck!  Let us know how it turns out.

Dear Green Plastics,

Thank you for the great video! I will use it for my school project. But... do you know the chemical formula for the bioplastic it makes? I want to make sure I get it right.

RESPONSE FROM GREEN-PLASTICS.NET:

Hello!  Thank you for your question, and I'm glad you would like to use this for your school project.

The plastic in the video is made from combining a polymer -- starch -- with a plasticizer -- glycerin -- and each of these has its own chemical formula which you can find fairly easily by doing research online.

Starch

(C₆H₁₀O₅)_n

Glycerin

C₃H₅(OH)₃

It is generally true that a particular "type of bioplastic" will not have a single molecular formula, because each type of bioplastic is made up a combination of polymer, plasticizer and additives in different possible ratios.

In the case of this home-made bioplastic, it is still fairly simply because you have a small number of ingredients.  But when you are talking about professionally produced bioplastics—like the materials produced by NatureWorks LLC—they usually combine different types of polymers together, mixed with plasticizers and multiple types of additives as well, in different ratios.  Each one of these ingredients will have its own molecular formula.

Let's start with the basics.  What makes green plastics green?

According to the definition on the Green Plastics wiki:

What makes green plastics "green" is one or more of the following properties:

1. they are biodegradable
2. they are made from renewable ingredients
3. they have environmentally friendly processing

Because different compounds can satisfy some or all of these criteria to different degrees, there are different "degrees of green" in green plastics. To evaluate how "green" a plastic material is, you need to ask three questions:

1. how quickly can the plastic be re-integrated into the environment after it is no longer being used?
2. how quickly are the ingredients that go into making the plastic created in the environment?
3. how much pollution or waste is created during the process of actually making the plastic?

Most of the publicity surrounding green plastics centers on the first two points. ENSO Bottles uses an additive in their plastic so that it satisfies #1 but not #2.  Braskem's "green propylene" satisfies #2 but not #1.  The most informative articles circulating around on bioplastics recently have been trying to educate the public about the differences between "renewability" and "degradability".... that is, the difference between points #1 and #2.

While this distinction is important, it leaves out the less popular "third side" of "green" in "green plastics": #3, the production process.

This "third side" was launched into the headlines recently by NatureWorks.  According to the new press release,

The manufacture of NatureWorks' Ingeo™ plastic... emits fewer greenhouse gasses (GHGs) than the comparable manufacture of every other common petrochemical-based plastic, according to a peer-reviewed article published in the August 2010 edition of Industrial Biotechnology. The article, "The eco-profile for current Ingeo™ polylactide production," was peer reviewed and approved for publication in Industrial Biotechnology by an independent panel of experts. The article documents the energy and GHG inputs and outputs of Ingeo™ production, including planting, harvesting, fermenting plant sugars, and resin production.

This places NatureWorks' Ingeo™ plastic squarely ahead of most of the competition in the "green credentials" arena, satisfying all three of the points above.

Could NatureWorks' Ingeo be even greener?  There are always ways to be better.  Some company could find a way to make production even more environmentally friendly, or could produce a plastic with even better properties than Ingeo while retaining its bio-based content and biodegradability.

But for now, Ingeo sets a standard that demonstrates that we don't necesarily need the "trade-offs" between different aspects of green.  It is a standard that the rest of the bioplastics world should aspire to.

In the news today, Braskem Announces a Green Polypropylene Plant: the largest thermoplastic resin producer in the Americas will build the world's first manufacturing plant to produce "green propylene", a form of polypropylene made from renewable resources like sugar cane.  From their press-release: "The green polypropylene will have the same technical, processability and performance properties as polypropylene made using petroleum."

How is that?

One of the most well-known and often-discussed criticisms of bioplastics (for example, PLA) is that the properties of the final product do not quite match up with those of traditional plastics: it's not as strong, or not as heat-resistant, until you mix it in with other (usually non-green) chemicals and additives and binders.  At a fundamental level, the chemical structure of biopolymers is different from the chemical structure of artificial polymers... and so their resulting properties are different.

Here is the source of the success of "green polypropylene":

The chemical structure of "green polypropylene" is NOT different from the chemical structure of traditional, synthetic oil-based plastics.  There is not a single atom's worth of difference in the chemical structure.

The only difference is in how the polymer was created: in traditional plastics, the molecule is "built" from a process that starts with petroleum, in "green polypropylene" the molecule is "built" from a process that starts with sugar cane.  Once that molecule has been created, though, it is identical in every way to traditional plastics. 

To quote from the article in the most recent issue of bioplastics magazine: "Biobased polyethylene (and, once available, polypropylene) are NOT biodegradable. On the contrary, biobased PE and PP do not at all differ from petroleum based polyolefins. They have the same chemical structure and can be polymerized in the same way The same grades (film, injection, blow moulding, etc) can be created, and so on. The only difference is in the origin of the carbon.  Biobased polyolefins consist of renewable carbon."

Is that good or bad?

On the good side:

• It can be processed by existing plastics processing plants, so you don't have to build special new ones.
• It has the good properties of traditional plastics, like strength and heat and water resistence
• Creating it does not rely on oil, an unsafe and scarce non-renewable resource
• It can be safely recycled along with traditional plastics

On the bad side:

• Just like traditional plastic, it is not biodegradable

At first glance, of course, it seems like the good outweighs the bad.  When you look at the "two dimensions of green" -- renewability and degradability -- green polypropylene succeeds at one and fails at the other.  Isn't that a step in the right direction?  Isn't it a good thing, overall, to pursue every avenue for making plastics more environmentally friendly, even those that aren't environmentally "perfect"?  (We so often hear slogans these days like "pursue every option" or "don't let the perfect become the enemy of the good" and so on.)

I'm not saying I disagree. However, I think it is worthwhile to at least understand and think about the arguments from the other side.  Consider these questions:

What about the tonnes and tonnes of waste building up from discarded plastic?  Won't this simply continue to contribute to that problem?  Even though the carbon comes from renewable resources, once it's put into the "green propylene" it is trapped and will not be returned to the biosphere, because the product doesn't biodegrade.  Doesn't that do even more damage to the environment, by trapping what once was "free" carbon into these plastic products?

Some people will argue that green polypropylene is a "first step" technology, a way that we can be "more green right now" while we wait for the technology on biodegradable bioplastics to improve.  But if all of our industry starts getting geared up to this solution, will it simply delay our progress with plastics that are both based on renewable resources and biodegradable?

What do you think?

Dear Green Plastics,

Is there anything we can substitute for glycerin?

See, my group in school is building a parachute to hold an egg safely to ground... and we get parked up for making plastic. however we have to use materials from da vinci's time... so is there any alternative to glycerin that was around in da vinci's time? thanks!

RESPONSE FROM GREEN-PLASTICS.NET:

Hello!  Thank you for your question, and it sounds like an interesting challenge for your project.

Leonardo da Vinci was alive in the late 1400's and early 1500's.  Technology was fairly simple back then, but they did make soap!

This is important for you, because glycerol is actually a by-product of soap-making.  For a somewhat technical discussion of this relationship, check out the Wikipedia article on Soap.  The basic idea is that you take some kind of oil and mix it with a chemical called lye (both of these have been around for centuries), and the chemical reaction that results (called saponification) converts the triglycerides in the fat into fatty acid salt and glycerol.

I don't recommend that you actually try to make your own glycerol with this process.  Lye is very toxic and the whole thing can be quite messy.  However, I would recommend you approach your teacher and ask whether you can use store-bought glycerol, since chemically it is the same substance that could easily be found in the 1400's as a by-product of soap-making.

Then, I would recommend that you make your bioplastic using gelatin as the polymer and glycerol as the plasticizer. Gelatin is actually easier to work with than starch and will produce some nice, strong pieces of solid plastic.  In da Vinci's time, they would get gelatin by boiling pigs' feet for several hours.  (Again, instead of boiling pigs feet, I would suggest buying the gelatin from the store.)

What is the actual recipe?

Unfortunately, you were a little vague about what you want the plastic to be used for in your device, so I don't really know what kind of plastic you want.  I will give you two recipes for a gelatin-glycerol plastic: one will produce a thin flexible sheet that can be folded and cut with scissors, and the other will produce hard solid pieces of plastic that can be molded into buttons or other inflexible solid shapes.

THIN SHEET RECIPE

Combine 6.0 grams (2 tsp) gelatin with 320 ml (1 1/3 cup) of 1% glycerol solution and 160 ml (2/3 cup) water.

THICK SOLID OBJECT RECIPE

Combine 3.0 grams (1/2 tsp) glycerol and 12.0 g gelatin (4 tsp) with 60 ml (1/4 cup) hot water.

You will notice that the big difference in the recipes is simply the proportions of each part: the thin sheet needs more plasticizer, the hard pieces need much less.

For both recipes, mix all of the ingredients together in the amounts above, and stir.  Keep mixing until there are no clumps and it is as dispersed as it's going to get.  Then heat the mixture to 95 C or to when it starts to froth (whichever comes first). Stir the mixture while you are heating it, and once it is at the right temperature (or starts to froth), remove the heat and keep stirring.  Scoop out excess froth with a spoon, and make sure there are no clumps.  Carefully pour the mixture into a drying pan, and make sure to spread it out to let it dry. How long it takes will depend on the temperature and humidity in the room, and it may take several days (depending on your formulation). You won't be able to remove the plastic from the drying sheet easily until it is completely dry, so be patient!  If your first batch turns out too sticky or slimy, you can try it again with slightly less plasticizer.

Finally, one word of caution: These recipes are good for flexible sheets or solid parts, but if you are planning on making a mechanical object with moving parts, you are probably better off using traditional old-fashioned wood.

Good luck, and let us know how it turns out!

Today's big news:

SunChips not-so-quietly buries its noisy compostable bags
SunChips Sacks Its Line of Noisy Biodegradable Bags
Frito-Lay sends noisy, 'green' SunChips bag to the dump
Is Noise Really Why SunChips Should Ditch Bioplastic Packaging?

Here are the facts:

• 18 months ago Frito-Lay launched a biodegradable SunChips bag made from plant material that was billed as 100% compostable 
• Many people complained that the bags were too noisy, and specifically much noisier than the original packaging
• SunChips sales have declined more than 11% over the past 52 weeks, as reported by SymphonyIRI Group, the market research specialist.
• SunChips presumably makes the link: sales are down because people don't like the new bags
• SunChips decides to pull the new bags from production, while still looking for a "quieter" version of a compostable bag.

I'm sorry, but am I the only person who thinks that the data (points 1 - 3) do not support the conclusion (point 4)?

We live in an age where obsessed whiners can shout very loudly.  Facebook pages take no effort to create and even less effort to "like".  And the continual thrill-seeking media is anxious to report the funny (or thrilling, or stupid, or shocking) story that will pull viewers.  So the fact that some whiny people complained about noisy bags, some bored people thought it was funny and so "liked" a facebook page, and hystrionic media reported it as if it were news, suddenly leads some media consultant somewhere to conclude that the noisey bags actually drove consumer behavior. 

In other words: the bags get the blame for the 11% decrease in sales.

Is that a logical conclusion?

Let's be scientists for a moment. What is an alternative hypothesis? What other things do we know about our society, our economy, and our world that could possibly explain a decrease in (of all things) "SunChips" sales?

In a world where every day the headline is about unemployment, foreclosures, and debt, let's imagine that maybe people are spending less on expensive snack foods.  Let's put forward the hypothesis that when people are broke and hurting for money, they will want to spend less on food that has absolutely no nutritional value.

Now, with that hypothesis in mind, let's do a comparison of the price per ounce of some common snack foods:

The only snack food on the list that is more expensive per ounce than SunChips is Funyuns. (I wonder how their sales are doing?)

I'm sorry, SunChips, but I think we have a simpler explanation for why your sales might be declining in the last year.  And it's not your bags.

In the words of an oft-quoted politician: it's the economy, stupid.

Hi,

I tried out your procedure for making plastic from starch as my chem project, and I got an excellent thin blue plastic film. I haven't peeled off all of it from the aluminum foil yet..
I need to store the film at home for a few months so I can show it to the folks who are going to be grading the project later, so what would be the best way to store it?
I'm thinking of sandwiching the foil with the plastic between butter paper.. Is it a good idea?

Thanks for your great videos..
 

RESPONSE FROM GREEN-PLASTICS.NET:

Hello!  Thank you for your question.

I'd like to start by saying congratulations on your project!  It is great to hear about a success story.  If you would like to take photos or video of your end result and send them to us, we will post them here on the website, along with any comments or thoughts you might have about your experience making it.  Let us know!

To answer your question: Your best bet is to simply store it in a cool, dry place.  A cool air-conditioned room is best, although you can also keep it in the refrigerator if that is what you need to do to make sure it doesn't become to warm or too moist.  Your idea of sandwiching the plastic between butter paper is good, although the most important thing is to control the temperature.

Thank you for your email!

Recently I was listening to a local Dallas radio talk show that was discussing the recent Paris Motor Show 2010.  The woman who was the "on site reporter" was telling the host of the show that the one overwhelming theme of the show was: electric cars.  Every single manufacturer had at least one (but often several) new models of car that ranged from hybrid to fully electric.

But the reaction of the Dallas talk show host was stereotypical almost to the point of being cartoonish: complete with thick Texan drawl, he focuses on what obviously really matters: "How did they look?" and "But how do they expect these cars to get into the American market, when we don't have the infrastructure for electric yet?"

This second objection he felt was important enough to repeat several times, and he even ended his show with that commentary: It doesn't seem like a smart decision to be pushing all of these electric cars out, when here in the United States we don't have the infrastructure yet for them. 

Our friendly Dallas talk show host isn't alone in this mind-set, either.  According to one report, Ford Europe boss Stephen Odell expressed the same concern: "Frankly the technology needs to get better, with a longer range ... and the cost has got to come down. And there's the infrastructure -- where are you going to charge your car?"

I call this the "Chicken and Egg" argument against adopting new technology:

"It's stupid to build electric cars when there is no infrastructure to support them!" and "Why should we waste money on building an electric car infrastructure when nobody has electric cars?"

This argument got my attention, because it is the exact same argument that people in the United States use against moving toward bioplastics.

In Europe, in the world of bioplastics, just like in the world of electric cars, the outlook is progressive and forward-looking.  According to Steve Davies, director for corporate communications and public affairs at NatureWorks, the European market is upbeat. In July, the US-based biopolymer manufacturer boosted its presence in Europe by linking up with Trevira, a German polyester fibre specialist. "The European market is performing very well in some applications and solidly in others," explains Davies.

But just like in the electric car industry, the United States is falling behind.  Recent reports on technologies and global markets related to bioplastics say it outright:

Use of bioplastics got off to a faster start in Europe than in the United States. European usage is now reported at 175,320 metric tons in 2010 and is expected to increase at a 33.9% compound annual growth rate (CAGR) to reach 753,760 metric tons in 2015.

Even the most positive spin describes the United States as a places of "untapped opportunity":

Biome’s Mines also notes that in the US, there is an opportunity for growth. "The US market is starting to become aware of the issues and the potential of biomaterials although is still behind Europe," he observes.

Why is the United States chronically behind?  Based on what I've heard, it is the same chicken-and-egg mindset.  When you have been reading blogs and opinion pieces critical of bioplastics, what are the main objections you have heard?

• We can't start pushing compostable plastics, most people don't have "compost" bins, only "trash" and "recycle" bins
• We can't start pushing compostable plastics, because there aren't as many composting facilities as there are landfills
• We can't start pushing compostable plastics, because there are so few manufacturing facilities for it that it is too expensive to make in bulk.

How many of these sound familiar? Every single one of these arguments has the same format: the Chicken-and-Egg format.

From now on, every time you read or hear this type of argument against bioplastics, please remember to point this out:  This is a Chicken-and-Egg argument.  This is a "I won't do it until the other guy goes first!" argument.  It is not an argument against bioplastics in particular.  It is simply an argument against any kind of change.

download PDF

(The characters Achilles and the Tortoise are taken from Douglas Hofstadter's Goedel, Escher, Back: an Eternal Golden Braid.)

Achilles (a Greek warrior, fleetest of foot of all mortals)
comes across a Tortoise in a forest. The Tortoise is
smashing a plastic box with a hammer.

Achilles: Good afternoon, Tortoise. What on earth are you doing?

Tortoise: I am finished with this plastic packaging, so I am returning it to the earth.

Achilles: But all you are doing is hitting it with a hammer.

Tortoise: Actually, if you must know, I am degrading it.

Achilles: Degrading it? Well, hitting something with a hammer is rather insulting…

Tortoise: No, no. It just means that I'm breaking it down. You've heard of things being "biodegradable," right?

Achilles: Yes…

Tortoise: Well, biodegrading is just one kind of degrading, you know. Things can degrade in different ways. I am choosing to degrade this plastic… (heaves the hammer over his head, and brings it down one more time on the box)… in this way.

Achilles: Now wait, but that's hardly the same thing.

Tortoise: Why? I mean, suppose I break it down small enough…

Achilles: You'll never do it with a hammer.

Tortoise: Well, I could use a grinder of some sort.

Achilles: That wouldn't… look. You know what plastic is, right? It is made up of these big long molecules called polymers. Even if you use the hammer to separate it into little chunks, it's still made of these big long polymer molecules.

Tortoise: Aha, well now I've got you! I happen to know that there are things you can add to the plastic, that can break those polymer molecules!

Achilles: Something you can add now?

Tortoise: No, no. You have to add it when you are making the plastic. But work with me for a moment, ok?

Achilles: OK.

Tortoise: So when they make this plastic box, they can add things that make it sensitive to natural things in the environment. Like light. Leave it out in the sun, and the sun will actually act like scissors, snipping those long molecules into shorter bits. This makes the plastic very brittle, and eventually it will just fall apart on its own. That is called photodegradation. It's another kind of degradation.

Achilles: You wouldn't even have to hit it with a hammer?

Tortoise: No! Eventually, it would just crumble away naturally with erosion. You can also add things to the plastic so that water will do the same thing: scissor the molecules so that the plastic becomes brittle. That's called hydrolytic degradation. And, you can add chemicals to the plastic so that it will react with oxygen to become brittle. And that is called…

Achilles: Oxydolic-degradation?

Tortoise: Close. Oxidative degradation.

Achilles: But so what? It is brittle and it crumbles. And in the end you get plastic dust. Plastic powder. But it still isn't dirt. It's plastic sand.

Tortoise: So what? Same difference.

Achilles: It is not the same!

Tortoise: Why? When you are walking on the beach and stepping in a fine powdered sand, who cares if it is itsy-bitsy pieces of rock or itsy-bitsy pieces of plastic? Sand is sand. It's part of the earth. It's…

Achilles: Don't say it!

Tortoise: … it's natural!

Achilles: It is not natural. It's still plastic, no matter how small the pieces.

Tortoise: Why does it make a difference?

Achilles: Well, for one thing, it doesn't just end up on the beaches for you to walk on. It ends up building up in the oceans. I read somewhere¹ that marine animals eat these microscopic bits of plastic, and you can see it building up in their digestive systems.

Tortoise: Well, is it toxic?

Achilles: As far as we know, it's not toxic…

Tortoise: Aha!

Achilles: …but it can attract toxic materials. There was a study² that showed that degraded plastic residues can attract and hold toxins like PCB and DDT up to one million times normal levels. The PCB’s and DDT’s are already in the environment, but are usually so diluted that they are not a significant risk. However, plastic residues concentrate these chemicals, until they can build up to toxic levels.

Tortoise: OK, fine. But tell me how biodegradation is any different. Doesn't "biodegradable" just mean that something is broken into teeny-tiny bits by microbes and fungus and stuff, instead of by light or water?

Achilles: Well, no. When something biodegrades, the molecules are converted into a form that can actually be used by the cells of living organisms.

Tortoise: (blank stare) I don't know what that means.

Achilles: OK, let's start at the beginning again, then. These polymers I told you about, these long molecules?

Tortoise: Yes?

Achilles: They are long chains that are made up of carbon atoms. Cells like carbon atoms. They use carbon atoms to make energy.

Tortoise: Really? How?

Achilles: There is a biochemical process involving the participation of three metabolically interrelated processes… look, it's all very complicated, I'll lend you something to read³ about it some time.

Tortoise: Ok.

Achilles: Anyway, when the carbon atoms are in the long chain, they can't get inside the cells to be used for energy. Even when the polymers are broken down very short, they have to be in a particular form that can be brought inside the cells so that the cells can use them. When something is broken down into small pieces by biodegradation, it always is able to pass into the cells of the organism to get used. When something is broken down into small pieces by other types of degradation… who knows? The cells might be able to use it, they might not.

Tortoise: So you are saying, these other ways of degrading plastic might be the same as biodegradation, we just aren't sure…

Achilles: I'm saying that these other ways of degrading plastic might be the same as biodegradation under some circumstances, depending on the plastic and depending on the method, but even that we don't know for sure yet. It's a big question-mark.

Tortoise: If I just make sure that I hit the plastic really hard with the hammer…

Achilles: No! It's not enough. Whether the cells can get the carbon from the molecule depends on the chemical structure of the original polymer, not just on how small the pieces are. That's why it's better to use plastic that is made from plants instead of oil, because the chemical structure of those polymers is much easier for cells to work with.

Tortoise: So if the plastic is made from plant polymers, and then I hit it with the hammer…

Achilles: Hitting it with a hammer can help make biodegradation faster. But it doesn't biodegrade until the organisms actually use their own enzymes and stuff to break down the polymer so that the cells can use the carbon. That is biodegradation.

Tortoise: And anything that breaks down polymers in a way where the pieces can't be used by living cells?

Achilles: Anything that does that is not biodegradation. Which means it can build up inside organisms and attract toxins and who knows what else.

Tortoise: So the moral of the story is…

Achilles: The moral of the story is, biodegradation really matters, not just degradation!

Tortoise: … and hitting things with hammers always helps!

Achilles: (rolls his eyes)

NOTES:

1) Ramani Narayan, “Biodegradability…” Bioplastics Magazine, Jan. 2009. Narayan is a professor from the Department of Chemical Engineering and Materials Science at Michigan State University.

2) www.algalita.org/pelagic_plastic.html

3) Ramani Narayan, “Biodegradability…” Bioplastics Magazine, Jan. 2009. Narayan is a professor from the Department of Chemical Engineering and Materials Science at Michigan State University.

Hi,

I am a student in Hong Kong. Now, I have a school project about eco-protection. I am thinking to recycle leftovers to bioplastics, and I want to use coffee residue as the raw material.

However, my first question is: is it possible make use of coffee residue to produce bioplastic?

Anyone tried that before?

Thanks a lot.

Regards,

Franky

RESPONSE FROM GREEN-PLASTICS.NET:

Hello, Franky!  Thank you for your question.

The term "coffee residue" can refer to the husks of coffee plants and also to used coffee grounds.

The husks are very rich in cellulose, but (unfortunately) you can't extract it simply by boiling it in water, because it will not dissolve. Dissolving the cellulose has to be done by trained chemists using special conditions, and the solvents are quite hazardous. So this is not something you can readily do as a home project.

The coffee grounds are not a good source of cellulose.  It is possible to use them in the creation of plastic, but the process is very complex and, once again, can only really be done by trained chemists under certain conditions.  What they would have to do is grind the residue, extract some of the organic components with solvents, pyrolyze the remainder to carbon, and blend the pyrolyzed carbon with a polymer to produce a plastic. If the polymer is a thermosetting polymer like polyurethane, the carbon from the coffee residue acts as a filler and the material can be compression molded.

So if the intent behind your question is simply, "Is it possible to use coffee residue in the creation of plastic?" then the simple answer is "yes!"  Unfortunately, if the intent behind your question is, "Is coffee-residue plastic something that I can experiment with at home?" the answer is "probably not."

The Bankok Post reports that NatureWorks LLC, the world's number one bioplastic company, has been in talks with potential partners to jointly invest in a large-scale bioplastic plant in Thailand worth about $400 million.

This would be only the second large-scale polylactic acid (PLA) plant ever built: the first opened in 2003 in Nebraska.  According to the article:

NatureWorks is currently in the process of selecting the location of the 150,000-tonne facility. Brazil is among the candidates while other potential locations are Thailand, Malaysia and Singapore...  Three basic factors in the final decision are local availability of raw materials including tapioca and sugarcane, markets of the product, and incentive programmes.

This is fantastic news, of course: one of the biggest obstacles to the wide-spread use of PLA is the price, and a big component of the price of PLA is the fact that there simple isn't the same level of industrial infrastructure (such as manufacturing plants) that there is for regular plastics.

But in addition to the general "hurrah!" and promise of this article, one other thing caught my eye: "Three basic factors in the final decision are local availability of raw materials including tapioca and sugarcane, markets of the product, and incentive programmes."

In the United States, President Obama gets a lot of criticism in some circles for wanting to spend money to incentivize green energy and green industry more generally.  Some people say that the government shouldn't be trying to influence private businesses or the free market.

The problem with this mindset is that in other countries, the government is getting involved, is creating incentives for green businesses, and as a result these other countries could emerge as centers of leadership in important new industries.  According to recent reports, China is so dead set on incentivizing green industry that it is breaking international law to do so.  But their motivation is simple and obvious: the short-term cost of pouring government money into an infrastructure of green industry is easily outweighed by the long-term benefits of being the global leader in that industry.  The government is participating in the "free market" by making a very straight-forward market calculation.

And so is Natureworks, by the way.  They are also participating in the free market, and have calculated that they can maximize their profit and productivity by building their plants in locations where there are incentive programs to do so.  This isn't very complicated, from a business perspective.

So from a purely "free market" perspective, it is important to realize that a mindset dedicated to "smaller governments" and "keep the government out of business" is also a mindset that will be crippling the United States' ability to be a leader in the global Green Industry market.  Ultimately, it's a decision that is bad for the "free market" and bad for the United States.... not to mention, bad for the environment.

Our recent news article about algae as a source for bioplastic has received a lot of attention.  But there is something very important that it didn't tell you:

You can make your own bioplastic from algae.  And we will give you step-by-step instructions on how to do it.

It's a fun little science project.  You can do it in your kitchen, with stuff you buy at the grocery store.  And you can see what "algae bioplastic" really looks and feels like...

Hi, I wanted to know if you could send me detailed information about the generation of bio plastic, since I am a student of industrial design and I like that my thesis is about this subject.

Very good video!

My project is about generation of clothing.

I send a big greeting from Mar del Plata, Argentina!

RESPONSE FROM GREEN-PLASTICS.NET:

Hello, and thank you for your question!

I hate to sound like an advertisement, but honestly the best way to get a lot of detailed information about bioplastics, both the science behind it and the practice of making it, is to buy the book:

Green Plastics: An Introduction to the New Science of Biodegradable Plastics

It's under $40 on Amazon.com, and it has everything from a history of bioplastics to its use in different industries to specific "how to" recipes in the back that you can use to make different kinds. If you are really interested in this topic as your thesis, it is worthwhile to get and read this book as a reference.

The book is comprehensive.  Of course, there are also articles on this site that can help you, as well. We regularly post recipes and instructions on how to make your own bioplastic, and information about do-it-yourself projects.

If you watch the media for news of bioplastics (the way that we do, here at Green Plastics), you will have noticed that for the last few days the Big News has been cashew-based plastics.

The Independent announces:

A unique plastic made from cashew nut shells could be used in consumer electronics by 2013.

Japanese company NEC Corporation has announced the development of a first-of-its kind biomass-based plastic -- bio-plastic - produced using non-edible plant resources such as cashew nut shells. The plastic is durable enough to be used in electronic equipment and NEC expects that with continued research bio-plastic could be used in a range of electronic devices by 2014.

Everyone is applauding from every side. The plastic is durable, heat-resistant, and water-resistant, so it would be safe to use in all kinds of electronic equipment from cell phones to laptops. It would make the creation of electronic devices more environmentally friendly. And because it is based on cashew shells, we can make as much of it as we want to without endangering our own food supply.

But with all of the publicity surrounding this breakthrough, you might want to know a little more about the science behind it...

hi! im a freshmen student and I am inspired to do bioplastic as my investigatory project.

Can you help me by siting two hypothesis? (null and alternative) :)

Hi
Congratulations on the how to make bioplastics video
I was wondering if you could send me the list of materials
thank you

lasc

I am design art student and have tried your recipe for bioplastic
for a school project. However, the plastic never completely dried.

It either stayed spongy and wet or it cracked and became very thin.

I have used tapioca corn starch and vegetable glycernin with
pure white vinegar and tap water.

sSyreNe21 asks in a comment on our YouTube Video:

what kind of glycerin is that?
crude glycerin?...pls reply..anyone..
im begging u!!!

Reply from Green Plastics:

Glyercin (also called glycerol) is something you should be able to get at drugstores, or even online (use google to search for "buy glycerin" and you should get a lot of hits).  Glycerol is produced by the fermentation of sugar, or from vegetable and animal oils and fats, as a by-product of the manufacture of soaps and fatty acids.

The purpose of glycerin in the bioplastic recipe is that it acts as a plasticizer.  If you are a student, you may have access to a wider range of supplies through school.  If you do, you might want to get you hands on sorbitol, which also works as a plasticizer.

Glycerin and other small molecules, like sorbitol, increase the plasticity of cast films and sheets.  You can add them to some form of polymer --- in the case of the video, use plain starch like cornstarch.

To make bioplastic, you always want at least one polymer and at least one plasticizer, but remember you can play around with different amounts of each--and when you have access to more than one type of polymer or plasticizer, you can try them in different combinations, as well.

Experiment until you get it right: the more plasticizer you use, the more flexible the end result will be; but use too much, and the end result will be tacky and will never dry.

Comment here if you have more questions, and happy experimenting!

Hi!

I’m a senior student in a science high school in the Philippines. We are required to make an investigatory project, and my group mates and I thought of making bioplastic from cassava (Manihot esculenta) sap and chitin from leftover crab shells. We gathered lots of information from different materials, mostly from the Internet. Just two weeks ago, we came across a video in YouTube and we thought that we can pattern our methodology from the one used in the video. That video was the one featured in your website.

Here is one of the procedures, as well as the materials we used in our experiment. By the way, we used crushed crab shells.

Methodologies:

- Extraction of Chitin (from Crab shells)

1. Dilute solution of sodium hydroxide (1-10%) at high temperature (85-100°C)

2. Demineralization (treating in a dilute solution of hydrochloric acid (1-10%) at room temperature)

3. Decolorizing process – obtaining white chitin (organic solvents/very dilute solution of sodium hypochlorite)

Depending on the severity of these treatments such as temperature, duration, concentration of the chemicals, concentration and size of the crushed shells, the physico-chemical characteristics of the extracted chitin will vary. For instance, the three most important characteristics of the chitin i.e., degree of polymerization, acetylation and purity, will be affected.

We tried doing it, but didn’t get any good results. We expected to also see the clear paste we saw in the video, but all we got was a yellowish, sort-of viscous liquid. After the experiment, we tried weighing things down, and came up with the following:

1. We have read what chitin is, but we’re not sure what it really looks like.

2. And since we don’t really have a clear idea on what chitin is, we weren’t able to make the bioplastic.

Now, we thought of asking help from you and the other guys featured on the site. We really want to be successful in this, because this project was chosen along with a few others to represent our school in an upcoming local science fair. Do you have anything to say about our methodology or materials that made our trial a failure?

We would really appreciate it if you would help us. If we did it right, we’ll let you know what the results are. Thank you very much! :)

Little problem here...

I just made a batch and after 24 hours it is as wet as the moment I poured it.

Will it ever dry?

You claim that you can make it as thin or thick as you want.   I just poured it on tinfoil and did not spread it at all. It all evened out and it is a puddle only a couple of millimeters thick.

Has anyone else who has followed the instructions in the video had the same problem?