What are Bioplastics? Discover 4 shocking types of bioplastic
Due to the problems related to the production, consumption, and disposal of plastic mentioned in our previous article, researchers have been trying to discover new materials.
As we discussed in the other article, bioplastics emerged bringing the promise of being more sustainable for the environment and less harmful for the human body.
However, the use and the concept of “bioplastic” are controversial. Not everyone believes that they are the solution to the numerous problems caused by plastic mentioned before. Researchers worldwide argue that its use should be done with caution and advocate for the need to expand researches and tests to prove the benefits of bioplastics.
Source: European Bioplastics
According to the European Bioplastics, “a plastic material is defined as a bioplastic if it is either biobased, biodegradable, or features both properties.”
According to European Bioplastics, “The family of bioplastics is divided into three main groups”:
- bio-based or partly bio-based, non-biodegradable plastics such as bio-based PE, PP, or PET (so-called drop-ins) and bio-based technical performance polymers such as PTT or TPC-ET;
- plastics that are both bio-based and biodegradable, such as PLA and PHA or PBS;
- plastics that are based on fossil resources and are biodegradable, such as PBAT.
Common sense often says that bioplastics are derived from natural sources and are biodegradable. But there are many discussions in this regard. To better understand that, we need to talk about the different types of bioplastic available on the market.
Plant-based: Polylactic acid (PLA)
This term refers to plastics derived from biomass (renewable energies). As an example of this type of plastic, we can mention those made from corn, cane sugar, avocado, cassava, and cellulose, called lactic polyacid (PLA).
The applications for this type of bioplastic are diverse and include plastic packaging and market bags, bottles, pens, glasses, lids, cutlery, glasses, trays, plates, 3D printing filaments, medical devices, and others (ECycle ).
Polybutylene adipate terephthalate (PBAT)
Polybutylene adipate terephthalate (PBAT) is produced from petroleum. However, it is biodegradable and compostable, which is why it is also considered a bioplastic. Ecycle explains that the properties of this, which is also considered a bioplastic, allow the polyurethane to replace low-density polyethylene, a plastic produced from petroleum that is not biodegradable.
Long Jiang, Michael P. Wolcott, and Jinwen Zhang explain the differences between PLA and PBAT: “PLA is high in strength and modulus (63 MPa and 3.4 GPa, respectively) but brittle (strain at break 3.8%) while PBAT is flexible and tough (strain at break ∼710%)” (Study of Biodegradable Polylactide/Poly(butylene adipate-co-terephthalate) Blends, 2006)
Bioplastic drop-in, hybrid plastic
The legislation of countries like the United States and Brazil allows hybrid versions of plastic. They allow mixing traditional petroleum-based plastic (non-renewable energy) with plastic from biomass (made from renewable energy sources, such as corn). This type of hybrid plastic, “mixed”, is also referred to in the literature as “drop-in bioplastics.”
Ecycle reports that the main bioplastics, or biopolymers, drop-in on the market today are bio-polyethylene (PE), bio-polypropylene (PP), polyvinyl chloride (PVC) and bio-polyethylene terephthalate (PET). This last one is today the drop-in bioplastic most produced, representing approximately 40% of the global bioplastics production capacity.
Ecycle highlights an example of drop-in plastic present on the market today, the Plant Bottle, used by one of the world’s leading soft drink manufacturers. In its manufacture, the bottle uses 30% of plant-based materials and the rest derived from petroleum.
Polyhydroxyalkanoate bioplastics (PHA). It is a bioplastic produced in different ways by bacteria.
Ecycle highlights that initially, the commercialization of PHA was hampered by high production costs, low yields, and limited availability, making it unable to compete with plastics of petrochemical origin. However, a specific type of bacteria is capable of producing PHA from a variety of carbon sources, including effluent residues, vegetable oils, fatty acids, alkanes, and simple carbohydrates.
The company Full Cycle has been producing polyhydroxyalkanoate bioplastics (PHA).
Are bioplastics compostable or can be recycled?
Above, we mentioned some of the main types of bioplastics. Still, it is essential to know that nowadays there is a vast offer of bioplastics on the market and that the variety does not end in the examples mentioned here.
Each of these types of bioplastics has different characteristics and possibilities for recycling and composting. In the next article from this series, we will talk specifically about these two topics.
To check our previous article about plastic, check here.