Bioplastics A Sustainable, Eco-friendly, and Economically Viable Future

William Loeffler - Nov. 2019

BIOPLASTICS - WILLIAM LOEFFLER

Executive Summary

Pollution - this can be caused by many things and can affect even more. Plastics are a common pollutant and in recent years, companies and researchers from all backgrounds have searched for ways to mitigate and lessen pollution due to plastics. Many of these measures involve recycling and other reactive approaches. While this is not a bad approach, it is not innovative and is slightly outdated. This is why in recent years the focus has shifted to a proactive approach. Some companies have tried to minimize the amount of plastic going into their products; however this does not solve the end problem of how long the plastic takes to decompose/ degrade when it gets out into the environment and animals ecosystems. This has caused recent research to shift to the idea of bioplastics. These plastics promise to be better for the environment because they will biodegrade many times faster than traditional petroleum based plastics, but also have the potential to be less expensive and stronger. Additionally, there are many different varieties of bioplastic, some which can decompose in water, while others get stronger in water. Some can be made from widely available production materials, and others can be made from previously unused by products such as rice straw and tomato skins. These plastics can be used across many industries from everything like packaging, to auto parts, and even sea turtle friendly straws.

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Table of Contents

1 - Introduction

1 - What are Bioplastics

2 - Initial Problems

2 - Solutions

3 - How They are Formed

5 - Benefits of Bioplastics

6 - Potential Uses

7 - Infographic

8 - About the Author

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Introduction

We are all familiar with the destruction pollution brings to the Earth’s - our - environment. Since the bronze age, carbon and other pollutants have been added to the atmosphere in ever increasing quantities. With the advent of the automobile, carbon dioxide emissions and other dangerous gases have been poured into our air like never before. These however, are not the only pollutants. Plastics are used every where - from cars, to toys, computers and more. “The production of plastics has increased substantially over the last 70 years from nearly 0.5 million tons in 1950 to over 365 million tons in 2016 worldwide” says Bilo5. A use of plastic was as a replacement to paper bags to help stem deforestation; however, now they have come full circle to become part of the very pollution they sought to destroy. Recycling is an option, but it is not a good one. It is reactive. Most plastics end up in landfills - regardless if you put them in the “recycling bin” or not. This is due to the selective nature of what “can” be recycled. In these landfills, they will spend at least 450 years decomposing into their respective petroleum base3. If recycling makes it past the landfill, it is likely shipped off to an Asian/ African country who has the complex technology and economic processes needed to support the recycling process - surely there are many of these? Also, if economic tensions rise between us and the countries we have paid to recycle, surely they wouldn’t send our plastic back and “recycle” it using their well developed recycling programs - not send it back to us, right? Because these problems exist, we need to examine a proactive approach to prevent plastic pollution. Bioplastics are a recent trend in research that promise to provide a proactive solution to the plastic pollution problem. In this white paper, we will examine the initial problems associated with bioplastic production, modern solutions to these problems, and finally briefly examine proposed processes to manufacture bioplastics. This will help you, the environmentally forward thinking and awoke member of society educate others and help save our planet from ourselves.

What Are Bioplastics?

Bioplastics are exactly what they sound like. They are plastics. The key difference between bioplastics and traditional plastics are the materials from which they are made. Traditional plastics are petroleum based, and consist of long polymers. Because of this, they do not

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3 -RYAN, C., BILLINGTON, S., & CRIDDLE, C. (2017). ASSESSMENT OF MODELS FOR ANAEROBIC BIODEGRADATION OF A MODEL BIOPLASTIC: POLY(HYDROXYBUTYRATE-CO-HYDROXYVALERATE). BIORESOURCE TECHNOLOGY, 227, 205–213. HTTPS://DOI.ORG/10.1016/J.BIORTECH.2016.11.1195 - BILO, F., PANDINI, S., SARTORE, L., DEPERO, L., GARGIULO, G., BONASSI, A., … BONTEMPI, E. (2018). A SUSTAINABLE BIOPLASTIC OBTAINED FROM RICE STRAW. JOURNAL OF CLEANER PRODUCTION, 200, 357–368. HTTPS://DOI.ORG/10.1016/J.JCLEPRO.2018.07.252

decompose fast. Bioplastics can be made from a variety of sources other than petroleum - commonly simple commonly occurring organic compounds. These sources are more eco-friendly and can be designed to degrade much faster than traditional plastics - as short as the amount of time as a banana peel or apple core. Like their petroleum based brothers, bioplastics take many forms ranging from rigid structural pieces, to foams like polystyrene. Generally, the idea with bioplastics is that they will be made from materials which are byproducts of other reactions, readily available, or ones which would otherwise be discarded as trash.

Initial Problems

As with all new inventions and research topics, the first try is not perfect - similar to riding a bike. The most glaring issue with bioplastics was their cost. PLA is a commonly researched bioplastic, however it has not replaced current petroleum based plastics because of its cost to produce6. This is common with other bioplastics such as ones derived from dried rice and PHBV3,4. These costs can range from 3-10 times as much as a petroleum based plastic, which is major problem for those of us who which to stay on the bleeding edge of environmental safety-ness. It also presents yet another opportunity for those not inclined to be environmentally conscious to turn a blind eye. This stems partially from the need to research the new product, but mostly from the lack of equipment available to make them. This requires specialized equipment to be made.

Another problem holding back bioplastics was their strength. Shopping bags and PVC pipes are both plastic, however PVC pipes are much stronger than their bag counterparts. Until recently, bioplastics had not been developed to a tensile strength great enough to be used in many practical “real” world applications6.Additionally they can be too hard, too brittle, and not strong enough to be useful. Now that has changed, and we can begin to show the world how easy it is to be environmentally safe. Newly developed plastics made from rice flower, and corn byproducts have been tested to have a tensile strength close to that of traditional plastics such as PVC (polyvinyl chloride) and LDPE(low density polyethylene), making them much more usable in day-to-day life.

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6 - King, A. (2015). Plastics & polymers Cheaper, greener bioplastic. Chemistry & Industry, 79(8), 6–6.3 - Ryan, C., Billington, S., & Criddle, C. (2017). Assessment of models for anaerobic biodegradation of a model bioplastic:

Poly(hydroxybutyrate-co-hydroxyvalerate). Bioresource Technology, 227, 205–213. https://doi.org/10.1016/j.biortech.2016.11.1194 - Biochemistry: Bioplastic made from glucose. (2016). Nature, 532(7598), 151. https://doi.org/10.1038/532151d

Solutions

The world is always developing and changing, and luckily so is the world of bioplastics. Many college and university researchers are working on ways to reduce the cost of manufacturing these bioplastics. Since this problem is so well known, automakers like Ford, clothing companies such as Nike, and even condiment manufacturers such as Heinz are all chipping in and looking into ways to bring bioplastics to the mainstream. Their financial contributions help push the development along. Recently, researchers in Belgium devised a new process that helped greatly reduce the cost to produce PLA, a bioplastic that degrades quickly, and is commonly used in drinking cups and packaging. They modified a two step process that was previously used to manufacture PLA, and reduced it to one6. In doing so they not only achieved few steps and less energy consumed, but they managed to increase the yield of the process by 40%. Similarly, a bioplastic similar to polystyrene has recently come about, and is manufactured under the trade name Glycix2. This bioplastic is perhaps not new, but its revolutionary in its use. Scientists that “rediscovered” it stated that it might have been discarded as waste before. However, now that they have a way to separate it out, it shows great promise.

How They Are Formed

There are many processes to form bioplastics, some are similar to ways that traditional petroleum plastics are formed, and others use completely new - even revolutionary - methods. For example, polymerization is a common method to make plastics. Glycix uses this method2. In this method, glycerol and critic acid (common in orange juice and other fruits) are mixed in a chamber. Before this material has cured, it is very sticky. It will stick to metal, glass, and pretty much everything except for silicone and other rubbers. However, once it is cured, it is no longer sticky and can be used in place of styrofoam. Another bioplastic seeing coverage lately is one made from rice straw5. Rice straw is a byproduct of agricultural production and is generally not saved. Instead, it is left to biodegrade into the soil. The rice straw is put into a Naviglio extractor (a solid-liquid extractor) first. Then it is dissolved by tri- fluoroacetic acid. This process can yield a plastic which is either wet or dry. The wet version has a strength comparable to that of PVC, while the dry version is comparable to that of polystyrene.

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2 - Alberts, A., & Rothenberg, G. (2017). Plantics-GX: a biodegradable and cost-effective thermoset plastic that is 100% plant-based. Faraday Discussions, 202, 111–120. https://doi.org/10.1039/c7fd00054e5 - Bilo, F., Pandini, S., Sartore, L., Depero, L., Gargiulo, G., Bonassi, A., … Bontempi, E. (2018). A sustainable bioplastic obtained from rice straw. Journal of Cleaner Production, 200, 357–368. https://doi.org/10.1016/j.jclepro.2018.07.2524 - Biochemistry: Bioplastic made from glucose. (2016). Nature, 532(7598), 151. https://doi.org/10.1038/532151d6 - King, A. (2015). Plastics & polymers Cheaper, greener bioplastic. Chemistry & Industry, 79(8), 6–6.

A different approach to make bioplastics involves using microorganisms4. Scientists have been able to produce PHB (a bioplastic) from various microorganisms by changing their metabolic systems to these plastics from glucose - a naturally occurring sugar. This can lead to lower production costs, which will aid in making the plastic more marketable. All of this is done with ethical treatment in mind and does not harm the organisms.

Other bioplstics, such as PLA and related ones, are made using a fermentation process6. This process involves the fermentation of sugars, such as glucose at high temperatures, which forms lactic acid. This lactic acid is then fed into a reactor where is is put under a vacuum, and mixed with a catalyst, to remove the lactide, and leave unwanted oligomers. This lactide can later be repolymerized to form the PLA bioplastic. This is a long process, and has made it not cost effective for main stream use - as mentioned before. Recently, this process has been modified from a two step one, with poor yield rates of 50% - the aforementioned process, to a single step, faster fermentation process with yield rates ranging from 80-90%. This new process “… tackles a real-life problem [of plastic pollution]. People do not want to pay a lot for [plastics], so the cheaper you can make the [PLA] the more people will use it.” says Cole-

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5 - Bilo, F., Pandini, S., Sartore, L., Depero, L., Gargiulo, G., Bonassi, A., … Bontempi, E. (2018). A sustainable bioplastic obtained from rice straw. Journal of Cleaner Production, 200, 357–368. https://doi.org/10.1016/j.jclepro.2018.07.2523 - Ryan, C., Billington, S., & Criddle, C. (2017). Assessment of models for anaerobic biodegradation of a model bioplastic: Poly(hydroxybutyrate-co-hydroxyvalerate). Bioresource Technology, 227, 205–213. https://doi.org/10.1016/j.biortech.2016.11.119

Production capability estimates of bioplastics in tons per year 7

Hamilton, a professor of chemistry who has been working on this project6. This reduction has been accomplished through the use of zeolites. Zeolites act as catalysts, and are small crystalline materials. Zeolites not only allow for a reduction in time of lactic acid formation, but also reduce the heat required to ferment the sugars, which is a “significant advantage in a commercial process”6.

Benefits of Bioplastics

The benefits of bioplastics are many. Most notably, is their ability to biodegrade faster than that of their petroleum based counterparts, which take at least 450 years to decompose. Different bioplastics can be engineered to take different amounts of time to decompose, but their times are fractional compared to petroleum plastics. Bioplastics have different environments in which they will decompose better, and they can be chosen for their use. For example, it makes little sense to package water in a bioplastic bottle that decomposes in the presence of water, and it makes little sense to make a plastic shovel that decomposes upon contact of dirt.

PHB, another bioplastic does not decompose in soil nor water. It is interesting in that it can be decomposed by anaerobic digestion. This is the process by which microorganisms

breakdown a substance in the absence of oxygen3. This is a chemical process with an interesting benefit. As the bioplastic is anaerobically decomposed, the microorganisms emit methane gas. While some may consider this detrimental, it is a positive outcome. This gas can easily be collected if done in a controlled environment, and used to power methane powered products, without the need for fossil fuels from

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2 - Alberts, A., & Rothenberg, G. (2017). Plantics-GX: a biodegradable and cost-effective thermoset plastic that is 100% plant-based. Faraday Discussions, 202, 111–120. https://doi.org/10.1039/c7fd00054e

1 - Tom-auto: car-ketchup collaboration enables plant-based plastic.(of material interest). (2014). Advanced Materials & Processes, 172(11).

Rice straw bioplastic (top) and PET plastic (bottom) decomposition at day intervals while emerged in soil5

the earth. PHB typically takes 42 days to decompose in this method3. In the referenced study, the scientists noticed that as particle size decreed and surface area increased, the peak methane production and decomposition rate was achieved quicker. This is due to the higher surface area allowing more microorganisms to attach to the substance. This leads to the idea that “preprocessing” of bioplastics for recycling might aid in the speed of which they can be degraded.

The aforementioned rice straw bioplastic shows excellent decomposing times in soil. This makes is suitable for uses in non-soil contact applications. It was compared to typical PET plastic (polyethylene terephthalate), which is commonly used for food and water packaging, and a few others. PET plastic takes a very long time to decompose. Studied in a lab, rice straw bioplastic was “fully decomposed” in soil in the short time span of 105 days5. On the converse, the PET plastic had not changed shape, nor shown any signs of decomposing.

The most widely available bioplastic to date - Glycix - decomposes is yet another way. Glycix is a plastic like polystyrene and is a solid foam. Glycix and its related bioplastics decompose and degrade in the presence of water unlike most all petroleum based plastics to date. Petroleum based plastics are hydrophobic, meaning they repel water. This is due to the nature of their polymer chains having very few open oxygen atoms to bond. This is mostly a positive thing though, as it makes plastics like PVC - commonly used in water and sewer applications - very durable. Glycix has different applications and therefore does not need the same amount of water durability. It has many more open oxygen atoms in the form of -OH and -COOH subgroups2. This allows for this bioplastic to readily decompose in the presence of water, or other moist substances like soil. The water bonds to the open subgroups, and the bioplastic returns to its original substances of citric acid and glycerol through a process known as hydrolysis.

Potential Uses

There are about as many uses for bioplastics as there are for traditional plastics; however due to the nature of how bioplastics decompose, their use case must be more carefully selected - as eluded to in previous sections. Glycix is well suited for uses where its inherent stickiness can be utilized. This makes it a good candidate for insulation in buildings or between two sheets of glass or metal, and other similar industrial applications that rarely see water. Additionally, it could be made to use for temporary straws that quickly decompose. PHB based bioplastics can be used in applications that must see water, so they are a potential replacement for plastic pipes and other tubing. Ford Motor Co. and Heinz Co. have partnered, along with others to research tomato fibers for use in automobile applications1.

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Heinz has noted that most of the tomato skins go to waste, and this is an interesting avenue to explore to not only reduce waste, but to make something useful out of it. This is a common theme within bioplastic research - to reuse and repurpose what has generally been thought of as waste. This is similar to the bioplastics evolved from rice straw - which has an estimated 100 million tons generated and unused each year5.

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5 - Bilo, F., Pandini, S., Sartore, L., Depero, L., Gargiulo, G., Bonassi, A., … Bontempi, E. (2018). A sustainable bioplastic obtained from rice straw. Journal of Cleaner Production, 200, 357–368. https://doi.org/10.1016/j.jclepro.2018.07.252

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About the Author

William Loeffler is a Computer Science student at George Mason University. He has many interests in the computing realm including data science and low level programming. Outside of technology, he cares for the environment. He enjoys staying up to date on recent recycling techniques, and is always looking for ways to improve our ecosystem and climate.

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Reference List

Tom-auto: car-ketchup collaboration enables plant-based plastic.(of material interest). (2014). Advanced Materials & Processes, 172(11).

Alberts, A., & Rothenberg, G. (2017). Plantics-GX: a biodegradable and cost-effective thermoset plastic that is 100% plant-based. Faraday Discussions, 202, 111–120. https://doi.org/10.1039/c7fd00054e

Ryan, C., Billington, S., & Criddle, C. (2017). Assessment of models for anaerobic biodegradation of a model bioplastic: Poly(hydroxybutyrate-co-hydroxyvalerate). Bioresource Technology, 227, 205–213. https://doi.org/10.1016/j.biortech.2016.11.119

Biochemistry: Bioplastic made from glucose. (2016). Nature, 532(7598), 151. https://doi.org/10.1038/532151d

Bilo, F., Pandini, S., Sartore, L., Depero, L., Gargiulo, G., Bonassi, A., … Bontempi, E. (2018). A sustainable bioplastic obtained from rice straw. Journal of Cleaner Production, 200, 357–368. https://doi.org/10.1016/j.jclepro.2018.07.252

King, A. (2015). Plastics & polymers Cheaper, greener bioplastic. Chemistry & Industry, 79(8), 6–6.

Staff, P. T. (2017, November 29). Global market for bioplastics to grow by 20%. Retrieved from https://www.plasticstoday.com/packaging/global-market-bioplastics-grow-20/203039009457893.

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