Bio-based plastic is a plastic that is produced from plants, such as sugarcane. Does this provide a sustainable alternative to regular plastic? In this blog, Brazilian bio-based plastics producer Braskem with European headquarters in Rotterdam, answers all your questions around the sustainability of bio-based plastic; from its source to its end of life.
Sugarcane: a renewable source of sugar, plastic and energy
Bio-based plastics are made from plants, such as sugarcane and corn. At Braskem, we produce bio-based plastics from sugarcane in Brazil. At the plantations, sugarcane is harvested and processed by a mill where the sugarcane is crushed up to five times. In modern mills, the first press is mostly used to produce sugar. Subsequent presses extract residual sugars in order to create ethanol. This ethanol eventually becomes the raw material from which bio-based plastic is made.
The production of ethanol is not at the expense of the production of sugar, rather, it means that more of the plant is being used. In fact, a purpose is attributed to every byproduct! After the sugar is completely removed from the sugarcane, the left over fibers are fed to a power plant that generates heat to boil the sugar juice. Moreover, it generates electricity to power the mill. The excess power often helps powering the national grid,  reducing our dependency on fossil fuels. Finally, all other residues are circled back to the plantation as a source of water and nutrients, reducing the need for inorganic fertilizers that can have a high carbon footprint. What is key however, is that sugarcane is a renewable and unlike fossil raw materials, it grows back every season!
Plastic with a negative carbon footprint
By producing ethanol from sugarcane, we do not only reduce our dependency on fossil resources, we also capture CO2. Through photosynthesis, sugarcane takes CO2 from the air and a portion of this CO2 is locked into bio-ethanol, the basis of our bio-based plastic!
How does that work? At Braskem, the bio-ethanol is dehydrated and broken down into ethylene and water. The ethylene is then polymerized into plastic resins within our plants. Up to now, we have been producing different types of polyethylene and EVA, a polymer widely used in foams such as shoe soles. As this product stores the CO2 from the sugarcane, Braskem's bio-based plastic has a negative carbon footprint.
The difference between regular and bio-based plastic
The production process of bio-based plastic is not very different from how regular plastic is produced. Actually, the only difference is the raw material. Despite their different origin, bio-based plastic and regular plastic from Braskem have the same basis: ethylene. This bio-based plastic is called 'drop-in', meaning that the molecular composition is exactly the same as regular plastic. That is why the use, application, quality and recycling of Braskem's bio-based plastic is the same as that of normal plastic.
People can already find bio-based plastic in various places in society, especially in packaging and durable goods such as toys. Still, currently, bio-based plastic only accounts for 1% of all the plastic in the world. But as brand owners and retailers continue replacing regular plastics by drop-in bio-based alternatives, the relative share of bio-based plastics will increase in the years to come. Braskem is committed to accelerating this transition and plans to fivefold its current capacity by the end of the decade.
Bio-based plastic in the regular recycling stream
Because bio-based and regular plastic are both made from ethylene, Braskem's bio-based plastic can go along with the regular recycling stream and does not require investment in new plastics-converting machines. Still, this applies to bio-based polyethylene from Braskem, but not to all bio-based plastics in the world. Some bio-based plastics are bio-degradable. While that sounds like a good way to avoid plastic pollution, in practice, the biodegradation process mainly offers advantages for application where recycling isn't possible. Even in those cases, producers have the responsibility to make sure consumers are informed about the correct way to dispose their products and make sure consumers aren't tempted to litter a plastic that may take a long time to biodegrade. We continue to investigate biodegradable solutions but for now, we remain convinced that it is of greater value to recycle and reuse the bio-based plastic to create truly circular value chains.
Although drop-in bio-based plastics have a negative carbon footprint and can be used and recycled in the same way as regular plastics, the sustainability advantages do not preclude its challenges. As the current scale of bio-based plastics is smaller, we do not profit yet from economies of scale, meaning that opting for bio-based alternatives can require more investment. But overall, the outlook for bio-based plastics, with a social and environmentally responsible origin as well as circular end of life, does look promising.
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