Did you know that each year 120 kg of synthetic polymers derived from fossil fuels are used, per capita, in developed countries? We are warned that in a couple of decades there will be more plastic than fish in the sea. We talked to Lauri Vares, Senior Researcher of Organic Chemistry at the University of Tartu University of Tartu - Tartu Ülikool is an Estonian higher education institute. about the ways we can reduce the invasion of plastic and save the planet with bioplastics.
What exactly is the field of activity of the international project “BioStyrene” which commenced in 2019?
Due to the fact that currently all plastic is derived from fossil raw materials, we are urgently seeking ways to replace fossil resources with more sustainable ones. It would be ideal to take CO 2 directly from the air and convert it into necessary materials. In that case we would not need the Earth or its resources, but we are currently still learning about this approach and we are not able to execute it yet. The temporary solution then is to use low-quality biomass as raw material.
Therefore you want to produce bioplastics?
Yes, our broader goal is to produce biomass-based plastics. Bioplastic as a term is probably not the best one, because most thermally-processed polymeric materials belong under the general term “plastics.” This does not only include plastic bottles or packaging, but also paints and all sorts of surface layers and details used in automobiles which are not metal or ceramic.
Who is involved in the project?
The participants in our Estonian-Russian cross-border project are the St. Petersburg State Forest Technical University and two companies from the St. Petersburg region; the paint producer Vapa and Plastpolymer, which produces plastics based on polystyrene and wants to replace some of the fossil raw materials with lignin. Lignin is one of the components of wood. Another participant from the Estonian side is the Tartu City in the west of Estonia (pop. 91,000). -based company TBD Biodiscovery.
What are suitable raw materials for producing such plastic?
Among other things we use citric acid which is a very widely used chemical. It is also produced from biomass and mostly used as an additive in the food industry. It is found in most beverages, where citric acid gives flavour and regulates acidity. We realised that it is possible to chemically convert it into rigid plastics, which is suitable for high-tech applications.
This means that the plastic maintains its properties and shape at higher temperatures and is easily processible with existing methods and devices used by the plastic industry. A general problem with bio-based plastics is their softness. This means that even at moderate temperatures they tend to lose their shape and become soft. Such plastic is suitable for some applications, but can’t be used e.g. to serve hot drinks.
Therefore we use different starting materials or chemicals which can be directly derived from biomass. One of our strategies is to reduce the content of oxygen and the hydrophilicity of biomass. By doing this, we want to make the polymers more rigid so that they can tolerate higher temperatures and it would be easier to industrially process and reuse them.
How easy is it to reprocess a package which is covered with bioplastic?
This is something which requires separate attention. People tend to think that a product made of bioplastic is automatically biodegradable, but this is not necessarily the case. It is quite complicated to create a product which, on the one hand, is strong and durable and, on the other hand, biodegradable. Therefore, our main aim is to make products suitable for reuse or reprocessing. At the same time, when they happen to be disposed of in nature, they are not toxic, do not create microplastic and, after some time, will also decompose. Of course it is really important to reduce the number of products with a short life-span and we need to critically assess if we need so many things.
How much bioplastic is developed in the world and what are the results?
There is a lot of development work going on. Especially in the Western world, larger companies are very active and keep close attention to developments in this field. Bioplastic will definitely be on the market on a larger scale in the near future. We need to keep in mind that bioplastic has been actively developed only in the last five to ten years. There are no large and conceptual obstacles; rather there are attempts to bring down the price with technological innovations. This can change quickly when, for example, fossil raw materials are carbon taxed.
What else could be a raw material for bioplastic? Plastic for example is also made of cannabis? To what extent is this approach more environmentally friendly in comparison to plastic produced from oil?
This is something we pay a lot of attention to in our work. The use of bioplastic avoids the use of fossil resources. As a raw material, we are able to use a very low-quality biomass or leftover products which have little use elsewhere. Unfortunately, the life-span of many plastics is very short and a relatively small amount is efficiently recycled. For example, if you burn a package made of fossil raw materials, the CO 2 is immediately released into the atmosphere. Hence it makes no big difference if you use gasoline as a car fuel or produce plastic with a short life-span which you burn later.
What have been the biggest challenges of this project?
A challenge is definitely the price of potential bioplastic. Plastic with good properties tends to be more expensive. But this is no reason to avoid using it because, as production scales grow, the price will rapidly decrease. Secondly, it is evident that people prefer products made of biomass. Also fossil PET plastic which is used to produce widely spread PET bottles or clothing (polyester fabric) was very expensive when it first came onto the market, and it was only used to make niche projects like design bottles. As technology developed rapidly, PET has now become relatively cheap and now there is a bio-based alternative coming – a plastic called PEF.
I think it is not sensible to use agricultural raw materials. The resource should come from leftover products. One very interesting development is the pellet producer Graanul Invest Graanul invest is an Estonian wood pellet producer. ’s sugar factory in Imavere, where they utilise wood fractionation technology to make wood sugars and lignin. We collaborate with them on the testing of wood sugars and wood sugar can be made of alder, which is not used that much elsewhere. Also algae are a possible raw material for certain plastics, albeit in our climate we do not have the suitable types of algae.
One of the aims of the project is to use new solutions in large scale industry. When do you plan to achieve this?
I think at some point companies should take over this development. We can create the solution on a laboratory scale and give them recommendations and then proceed to work together with companies. At the moment we are making surface covers which are meant for the paper packages used in food industry, such as coffee cups and pizza boxes. We have tested them in one of the companies and the results are good. The coffee cup covered with our polymer enables [them] to serve hot drinks without problems and, as the first tests show, it is possible to recycle it as paper.
You aim is to save the planet, but what are your hopes of conquering the markets with bioplastic?
Our goal is to create products for use in high-tech applications. In addition to those already mentioned, there are opportunities in the automobile industry where plastics need to be very secure, stable and durable.