‘A great deal is already possible in the field of biobased plastics’

At Trioworld, we are always interested in sustainable developments in plastics. Someone who is also concerned with this is Christiaan Bolck at Wageningen University and Research. Bolck is responsible there for the applied research in the field of materials. An interview on how things stand at present.

Biobased, Biodegradable, Oxodegradable and Renewable

When it comes to sustainable plastics, you come across different terms: biobased, biodegradable, oxodegradable and renewable. What do those individual terms mean? Consumers sometimes see biobased and biodegradable as one and the same thing, but that is not correct, says Bolck. ‘Biobased says something about the origin of the material: that it’s made of biomass, or in other words, plants. Biodegradable says something about the properties of the materials, so that it’s biologically degradable.’

‘Oxodegradable’ is a far less well-known term to consumers and it is far less easy to link it to a sustainability claim, Bolck contends. ‘Oxodegradables are under a magnifying glass, because there isn’t very strong evidence that these polymers really degrade completely in contact with oxygen. According to some parties, you just create the plastic soup in this way. After all, small fragments of plastic remain that do not degrade completely.’ The UK therefore already has legislation to ban oxodegradables.

And then there are also renewable or circular plastics. ‘Renewables are made of raw materials that can be renewed. Those could be vegetable raw materials that are made through photosynthesis every year, but could also recycled plastics.’ ‘Renewable’ is therefore a broader term than ‘biobased’.

The advantages and disadvantages of the different types cannot be called generic, Bolck says. ‘Ultimately, it’s an enormous family of plastics. And they all have their own properties, that can all be an advantage or disadvantage in specific applications. The same applies for oil-based plastics. That is also a large family with advantages and disadvantages in the usage and end of life phase of products.’

Greenhouse effect

Most of the plastics that we know are currently made of oil. But as a society, we want to drop those. ‘Biobased is about replacing fossil raw materials, or oil, with renewable raw materials, or plants. That’s an advantage for reducing CO2 emissions, or in other words, reducing the greenhouse effect.’

Bolck is not very positive about the use of oil. ‘Where it’s produced, it causes pollution. And wars are fought over it. What’s more, in the production of vegetable raw materials there is less risk of accidents.’ But at the same time, you must also continue to think about risks in the production of biomass. ‘For example, you shouldn’t be chopping down rain forests because you want to produce biomass.’

Biobased plastics

What is the present position regarding biobased plastics? In his book Biobased Plastics, dating from 2012, Bolck wrote: ‘Biobased plastics are emerging faster than we thought’. He was right about that. Since then, more has indeed been produced and consumers are also more concerned about this.

That growth in production volumes is also seen at Dutch companies. ‘The joint venture of the Dutch company Corbion and the French Total company has built a large plant for polylactic acid in Thailand. And the Amsterdam company Avantium is opening a first commercial plant in Antwerp. They produce PEF, which is also a bioplastic.’

But, says Bolck, total production of plastics has also grown all over the world. And producers of bioplastics can barely keep pace with the total growth of the plastics industry.

The primary issues in 2011/2012 were also the climate, and the use of fossil raw materials. ‘There was a real drive to used biobased. In the meantime, people are also thinking about waste, about the end of life of plastics. There is now a great deal of attention to recycling and the plastic soup.’

Aren’t biobased plastics actually outdated now that there is a major drive to recycle plastic packaging? ‘No’, Bolck says. ‘They exist alongside each other. The ideal would be to reuse all your plastics. We have made a good start in the Netherlands, but there is still a long way to go before we actually reuse all our waste plastics. There are still many places in the world where there is no recycling at all. That’s why it’s important that plastics are biobased; you have to respond to loss in the system, or to growing demand. That’s what you want to use vegetable raw materials for.’


There is therefore growing attention to biobased plastics and certainly also to biodegradable plastics, but Bolck notes that there are still a fair number of prejudices about these. ‘In the industry, there is an idea that plastics of this kind are poorer quality than ordinary oil-based plastics, but in many cases that isn’t so. All that research has not been for nothing.

It’s also often thought that biobased plastics are expensive. If you look purely at the price per grain, then they do often still cost more than fossil plastics at the moment. But you could ask yourself whether fossil plastics are properly priced.’

Another prejudice is the idea that biobased plastics are more difficult to recycle. ‘At heart, that isn’t the case. In technical terms, they are usually just as easy or just as difficult to recycle as ordinary plastics.’ And the rain forest that has to be cut down to make them? ‘That’s also unnecessary. There is enough biomass to convert all plastics into biobased plastics.’

Then the argument that you need raw materials for biobased plastics that you could also use for food still crops up regularly. And the fact that you don’t use them for food is a problem. It’s true that you can use those raw materials for both purposes, says Bolck, but according to him, that is not the core of the matter.

‘There is no hunger because there is not enough food; there is hunger because of the availability of food and the distribution of wealth. In principle, enough food is produced. What is lacking is its distribution. I always say that people also earn their food with the production of plants, and those are often precisely poor people. If you give them a chance to earn more money, they can also eat better.’

And that argument doesn’t apply for oil. ‘That is often pumped up at a single location. And I would be less quick to argue that poor people benefit from that.’

Technical developments

Bolck and his colleagues are working hard to broaden the applicability of existing commercially available biobased and biodegradable plastics. ‘In order to make film from them, or certain foam products. We look at both the processing methods and at specific products. A great deal of research is being conducted into the functional benefits of applications. Such as with packaging.’

He also tells about a technical challenge regarding niche applications: ‘Can you use biodegradable plastics in a way that, for example, an agricultural and horticultural product will suffice during its functional life, but will also biodegrade in the soil in due course?’

But there are also technical limitations that restrict faster growth. For example, the fact that far from all markets can be served as yet. And the price is also a challenge. ‘That remains a real issue. People have to really want to make the switch. With the same suitability, many people will opt for biobased and biodegradable. So the will is there.’

Bolck does see a role that the government could play here. ‘For example, by levying a CO2 tax.’

The future of biobased and biodegradable

Bolck does have an idea of how the ideal world for plastic packaging would look. ‘That would be a world in which we give the product maximum protection with plastic packaging, so that it reaches the consumer in perfect condition. And that we do that with materials that can be used again after their initial use, and then yet again. But if that is not possible, or if loss in the system cannot be prevented, then the material should be biodegradable. And if you cannot cover demand for plastics through recycling, you work with biobased raw materials.’

According to Bolck, the best example of biobased plastics in packaging at the moment is the tomato tub made of tomato leaves. ‘You can use your food waste flows to make packaging. I think those are wonderful applications.’

How close is that ideal world? Bolck names three developments for which it will be exciting to see the outcomes: ‘Firstly, you see clear pressure on the climate and, therefore, a desire to abandon fossil fuels and to replace them with biobased fuels. The question is, will that really catch on?’

Secondly, in the field of recycling: ‘Just like other rich western countries, the Netherlands is taking very serious steps in that regard. But to be honest, only in the field of collection. The industry needs to work towards input, towards new products.’

And the third development concerns our perceptions of plastics, materials in general, and litter. ‘More and more producers are opting for a “better safe than sorry” approach. Obviously, sweets wrappers shouldn’t be thrown away into the environment, but if it does happen, it would be best if they were biodegradable.’ Producers are therefore responding to the behaviour of consumers. ‘For no matter how great Boyan Slat’s The Ocean Cleanup is, it is still an end of pipe solution. I believe that you really need to search further back in the pipeline.’

Finally, Bolck has one more piece of advice: ‘When there is demand for a more sustainable material, assume that it is available. And simply ask for it. At Trioworld, or ask us. For a great deal is already possible. And don’t assume that every prejudice is right. A great many materials simply are available and among those, there are plenty of possibilities to find the ideal answer.’