Hi everyone, I’m Büşra, the founder of PM Biomaterials. For the past nine years, I’ve dedicated my career to bioplastics, and four years ago, this passion evolved into a full-fledged company and manufacturing facility.
Throughout this journey, we’ve built substantial expertise in the bioplastics industry and have done our part to educate the market on this subject. But now, I believe it’s crucial to ensure that accurate information reaches everyone, which is why I decided to write this article.
I’ve noticed that both in Turkey and abroad, there are initiatives and aspiring entrepreneurs who mix various plastic wastes and present the result as an eco-friendly material, even calling it bioplastic. However, this kind of work requires meticulous attention and proper design; otherwise, you might end up creating products that cause more harm to the environment than good.
To get a better grasp of bioplastics, let’s start by taking a brief look at their history.
The History of Bioplastics
The history of bioplastics is rooted in humanity’s quest to create durable and functional products from natural materials. The modern development of bioplastics began in the early 20th century, with the discovery of polyhydroxyalkanoates (PHA) by French chemist Maurice Lemoigne in the 1920s. PHAs are polyesters produced by bacterial fermentation and are biologically degradable. However, it would take several decades for these materials to be used widely in commerce.
In the 1930s and 1940s, scientists began working on producing plastic-like materials from renewable sources such as corn and potatoes. For example, Henry Ford’s attempt to use soybean-based plastic panels in the automotive industry is an early example of the potential applications of bioplastics. However, the discovery and widespread adoption of petrochemical plastics based on fossil fuels significantly slowed the development of bioplastics.
Interest in bioplastics was reignited in the 1970s following the global oil crisis. The rise in oil prices and the need to reduce dependence on petrochemical resources stimulated bioplastic research. During this period, modern bioplastics such as polylactic acid (PLA) began to be developed. PLA is produced through the polymerization of lactic acid derived from natural sources like corn starch.
Throughout the 1980s and 1990s, the commercial applications of bioplastics began to increase. Particularly in Europe, research on the environmental benefits of bioplastics and regulatory incentives led to the broader adoption of these materials. In the early 2000s, with the rise of global environmental awareness, the use of bioplastics became even more widespread. However, in later years, PLA encountered significant failures and did not meet expectations.
Major Issues with PLA
PLA faces three major issues, all of which stem from a lack of end-to-end sustainability consciousness. For example, you might think that a biodegradable material is more environmentally friendly because it degrades in nature, but this is not true. I will discuss this topic in more detail in another article.
- Produced from the Wrong Source
The use of human food sources such as corn and sugar beets in the production of bioplastics presents a significant sustainability problem. For instance, it takes about 2.5 tons of corn to produce 1 ton of PLA. This means that 0.5 hectares (approximately 5,000 m²) of farmland are required for corn production. If 1 million tons of PLA are produced globally each year, 500,000 hectares of farmland would be needed, equivalent to the total arable land in Denmark. Such land use could have detrimental effects, contributing to a global food crisis.
Ethically, this situation must also be questioned. While more than 820 million people worldwide are struggling with hunger, using farmland for bioplastic production could jeopardize food security. Using staple food products like corn for PLA production could increase food prices and make it more difficult for people in low-income countries to access food. This issue fuels the “food vs. industrial products” debate.
Additionally, intensive agricultural production for PLA can have negative impacts on environmental sustainability. Large-scale corn production often requires high amounts of water, fertilizers, and pesticides. These chemicals can pollute water sources, reduce biodiversity, and degrade soil quality. Monoculture farming can also lead to ecosystem imbalances and soil erosion.
Finally, using crops like corn for bioplastic production can reduce their availability in the food market, driving up prices. This situation could cause social and economic problems, particularly in countries where corn is a staple food. During the 2007–2008 food crisis, increased demand for corn for biofuel production led to an over 80% increase in corn prices. A similar situation could occur with PLA production.
- Inefficient Production Model and High Carbon Footprint
The raw materials used for PLA production are typically agricultural products like corn or sugarcane. The production of these raw materials requires significant amounts of land, water, and energy. Since it takes approximately 2.5 tons of corn to produce 1 ton of PLA, extensive farmland is needed. Producing 1 ton of corn requires about 900 m³ of water, meaning 2,250 m³ of water is consumed to produce 1 ton of PLA. This high demand for land and water in PLA production can lead to food security issues, water scarcity, deforestation, soil fertility loss, and various socioeconomic problems.
PLA’s carbon footprint is often advertised as being low, but when you consider the energy consumption and emissions from agricultural activities during production, PLA’s carbon footprint is actually higher than that of petroleum-based plastics. Yes, you heard that right!
- Agricultural Emissions: Fertilizers, farming machinery, and other agricultural activities used in corn production contribute approximately 1.0–1.2 tons of CO2 emissions per ton of PLA. This highlights the direct impact of agricultural activities on the carbon footprint and increases PLA’s overall carbon emissions.
- Energy Intensity: Producing 1 ton of PLA requires approximately 54 GJ (gigajoules) of energy. This is about 35% more than the 40 GJ needed to produce 1 ton of conventional plastic (e.g., polyethylene). High energy consumption increases PLA’s carbon footprint and limits its environmental advantages.
- Fossil Fuel Use: Much of the energy used in PLA production still comes from fossil fuels. This undermines the claim of a low carbon footprint and raises questions about the environmental sustainability of PLA production.
- Fermentation and Polymerization: The two main stages of PLA production, fermentation and polymerization, consume significant amounts of energy and contribute notably to carbon emissions. For example, the fermentation process alone can result in approximately 1.2–1.5 tons of CO2 emissions.
In total, producing 1 ton of PLA generates approximately 1.7–3.2 tons of CO2 equivalent emissions. This figure is comparable to or, in some cases, higher than the carbon emissions produced by traditional petrochemical plastics (e.g., polypropylene or polyethylene), which typically have a carbon footprint of 1.8–2.5 tons of CO2 equivalent.
- Failure to Meet Industry Needs
PLA faces significant challenges in meeting the requirements of industrial applications. High production costs, limited mechanical properties, and incompatibility with existing industrial processing systems make PLA less competitive compared to traditional plastics widely used in various industries.
- Low Heat Resistance: PLA’s glass transition temperature is typically around 55–60°C. This low heat resistance makes PLA unsuitable for applications exposed to high temperatures, such as automotive parts or hot beverage containers. In contrast, materials like polypropylene (PP) have a glass transition temperature of around -20°C, making them much more versatile for industrial applications.
- Brittleness: PLA is more brittle compared to many petroleum-based plastics. While PLA has an elongation at break of about 5–10%, polypropylene typically has an elongation of 200–700%, providing much greater flexibility and durability in final products.
- High Raw Material Costs: The production cost of PLA is higher than that of conventional plastics. PLA production typically costs around $2,200–$2,500 per ton, whereas the production cost of polypropylene is approximately $1,000–$1,200 per ton. This significant cost difference makes PLA less economically attractive for large-scale industrial applications.
- Energy Consumption: The PLA production process is energy-intensive. For instance, producing 1 ton of PLA consumes about 54 GJ (gigajoules) of energy, whereas traditional plastics (e.g., polyethylene) require only 40 GJ. This high energy consumption not only increases costs but also reduces the environmental benefits of PLA.
- Industrial Processing Limitations: Many industrial processes are optimized for materials like polypropylene and polyethylene. The temperatures, equipment calibration, and cycle times required for processing PLA differ significantly, often necessitating new machinery investments or adjustments. This can be both costly and time-consuming.
- Recycling Challenges: The recycling infrastructure for PLA is not as developed as that for petroleum-based plastics. Although PLA can technically be recycled, when mixed with other plastic types, it can contaminate the recycling process. This contamination increases operational costs and creates logistical complexity.
Bioplastics can be seen as an important step towards sustainability, but it’s clear that PLA, in its current form, falls short of meeting these expectations.
I’ve prepared a series of chapters to provide you with accurate information in this field. This was the first chapter of the series. See you in the next one!
Sources:
- Vink, E. T. H., Davies, S., & Kolstad, J. J. (2010). “The eco-profile for current Ingeo polylactide production.” Industrial Biotechnology, 6(4), 212–224.
- FAO (2020). “The State of Food Security and Nutrition in the World 2020.
- Tilman, D., Cassman, K. G., Matson, P. A., Naylor, R., & Polasky, S. (2002). “Agricultural sustainability and intensive production practices.” Nature, 418(6898), 671–677.
- Mitchell, D. (2008). “A Note on Rising Food Prices.” World Bank Policy Research Working Paper №4682.
- Vink, E. T. H., Rabago, K. R., Glassner, D. A., & Gruber, P. R. (2003). “Applications of life cycle assessment to NatureWorks™ polylactide (PLA) production.” Polymer Degradation and Stability, 80(3), 403–419.
- Madival, S., Auras, R., Singh, S. P., & Narayan, R. (2009). “Assessment of the environmental profile of PLA, PET and PS clamshell containers using LCA methodology.” Journal of Cleaner Production, 17(13), 1183–1194
- Shen, L., Haufe, J., & Patel, M. K. (2009). “Product overview and market projection of emerging bio-based plastics: PRO-BIP 2009.” Utrecht University.
- Vink, E. T. H., Davies, S., & Kolstad, J. J. (2010). “The eco-profile for current Ingeo polylactide production.” Industrial Biotechnology, 6(4), 212–22
- Auras, R., Lim, L. T., Selke, S. E. M., & Tsuji, H. (2010). “Poly(lactic acid): Synthesis, structures, properties, processing, and applications.” Wiley.
