Dreaming of plastic made of carbon dioxide
For Mistra STEPS, the goal is to develop bioplastics based on some form of renewable raw material, with properties similar or superior to those of present-day oil-based plastics. The problem is finding methods that cut the sky-high costs. But a year after the programme start, the first success is already here.
Problems with plastic are well known. In particular, the problem of microplastics has recently been much publicised. But the challenges are considerably more numerous: not least, the fact that most of the plastics we use today is made from fossil petroleum.
Nonetheless, there is no denying that plastic is a superb material, with properties we are reluctant to do without. The sole problem is finding alternatives to petroleum-based plastic that will not cost the earth.
This twofold challenge prompted Mistra, in 2016, to start the Sustainable Plastics and Transition Pathways (STEPS) programme.
‘When the call for proposals opened, there were already some research groups at Lund University that had been studying various aspects of bioplastics for several years. So, naturally, we began think about what we might do together within a programme,’ says Professor Rajni Hatti-Kaul, Programme Director of STEPS.
The programme also includes researchers from the Swedish University of Agricultural Sciences (SLU) and part of the Swedish Research Institute for Industrial Renewal and Sustainable Growth (Swerea IVF). In addition, Innovation and Chemical Industries in Sweden (IKEM) and Region Skåne, along with 18 different companies, are involved. Three of them are Perstorp, Electrolux and IKEA.
The programme focuses on three areas. In an initial set of tasks, a number of biobased building blocks will be produced. In the second, these will then be turned into useful polymers.
‘We want to develop bioplastics with various properties. If it’s a textile material we want to create, the polymer must have certain properties, but it has to have completely different ones if we’re going to develop a thin plastic film for the food industry. To succeed, the entire chain from raw material to finished product must function properly,’ says Hatti-Kaul.
In parallel, the researchers are looking at how the various materials could be recycled. Here, the difficulty is often to choose which way to go, not least because there may be a contradiction between a material being recyclable and degradable at the same time.
‘It’s not easy to get both properties in one and the same material. If it’s easily degradable, recycling it is less workable. The features we want in one case are quite simply problematic in the other. So we’re now considering whether there’s any way to trigger a degradation process when it’s needed.’
STEPS’s third work area is about policy issues and consumer behaviour. For example, companies are interviewed about their views and needs regarding plastic materials. Equally important is carrying out economic and environmental assessments of products and processes to better support the transition to innovative plastics.
In addition, the researchers analyse what is required for switching to more sustainable production, and for use of bioplastics to become reality. Objects of study therefore range widely, from political strategies and social dimensions to consumers’ wishes and needs.
The goal is to develop bioplastics based on some form of renewable raw material with properties similar or superior to today’s fossil-based plastics. To facilitate the transition to new plastics, it is important for manufacturing and processing them by means of existing equipment to be feasible.
In Sweden, forest waste is a conceivable source of raw material. Others may be agricultural residues or algae.
Nonetheless, the big dream is to be able to produce plastic from carbon dioxide. If this becomes possible, the gains would be significant. They would result both from reduced atmospheric carbon emissions and from plastics serving as a carbon sink. In addition, there would be gains because the other raw materials currently destined for bioplastics could be utilised in other areas.
‘We know it’s technically feasible to produce plastic from carbon dioxide. The question is more how economically viable such a transformation could be,’ says Hatti-Kaul.
Now, more than a year since the programme started, the work is in full swing in most areas. The exception is the research on how carbon dioxide could become a raw-material source for plastic.
Interest in bioplastics has grown considerably in recent years. According to the organisation European Bioplastics, global production capacity for bioplastics will increase from some 4.2 million tonnes in 2016 to about 6.1 million tonnes in 2021.
Packaging is the main application area. Bioplastics are also being used increasingly in the automotive, transport and construction sectors, which utilise technical bioplastics for which higher performance is required.
The most concrete result from STEPS so far is a floor paint made of sugar. A separate article describes it in more detail.
The researchers are also working with IKEA and Lindex to develop textile fibres of green origin.
‘IKEA and Lindex have told us what properties they want to see in a biobased textile fibre, and now we’re testing various building blocks to see how to get there. This is a good example of the value of the companies participating in the programme.’
Hatti-Kaul believes that companies have invaluable knowledge of all aspects of plastic materials — knowledge that researchers find extremely useful. The companies’ participation also means that the programme spans the entire value chain, from raw material to consumers.
‘I think it will help us obtain useful results,’ says Hatti-Kaul.
A floor varnish made of fructose was the first product created in the STEPS research programme. It is now being tested at Kemicentrum in Lund, so far to everyone’s satisfaction.
The STEPS researchers, jointly with product developers at the company Bona AB, have developed a floor varnish based on sugar.
‘We’ve developed a molecule that’s suitable for manufacture of polyurethanes, for example. With this as a starting point, Bona AB has produced a floor varnish that we’re now testing,’ says Professor Rajni Hatti-Kaul, Programme Director of the STEPS research programme.
At Lund University’s Kemicentrum, the new biobased varnish was applied to a wooden floor in a conference hall just before the summer. Although it is still passing a final judgment is still somewhat premature, there is ample indication that the varnish is of high quality.
‘Initial objectives were for the varnish to meet a number of requirements, including good scratch resistance and a high capacity to withstand alcohol, coffee and water. So far, in all these respects, everything looks very good.’
The environmental aspect was a key driver for the company Bona AB when it entered the project.
‘As well as the environmental benefit of a renewable raw-material base, we expect a longer life of the wear layer,’ says Nicola Rehnberg, who is responsible for Bona’s academic contacts.
‘The hope is that the floor will keep its appearance for longer, compared with a traditional varnish. In this way, we’ll both save materials for renovation and reduce the amount of wood used for the floor itself.’
The vision of the STEPS (Sustainable Plastics and Transition Pathway) research programme is for plastics to be developed, manufactured, used and recycled in a circular economy. Getting there calls for a transition to renewable raw materials, along with increased reuse and recycling of plastics.
STEPS wants to speed up this change-over. The academic researchers therefore collaborate with a large number of companies. Together, they analyse how a desired restructuring could be achieved and what it might mean for society and industry alike.