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“It’s not the material that’s the problem, it’s how we deal with the end product.”

An interview with Professor Dr.-Ing. Sven Friedrich, who is responsible for the Steinbeis Innovation Center for Engineering and Technology

Compostable plastics sound almost too good to be true. But will they really do away with that guilty feeling you have every time you throw away packaging? Unfortunately not, says Professor Sven Friedrich. The problems surrounding plastics, how they’re recycled, and material innovations are more complex than many realize. With his focus on SMEs, the Steinbeis Entrepreneur is working intensively on the challenges of using plastics in environmentally friendly and financially viable ways, even in times of climate crisis and cost pressure.

Hello Professor Friedrich. You work closely with plastics technology. The first question we must ask is: Are plastics really as bad as people say?

Most certainly not! Plastic is the material of the 21st century and life would be unimaginable without it. Throughout all sectors of industry, and for the large majority of applications, there aren’t any alternative materials capable of offering a suitable substitution.

The reason plastics have a bad reputation is that we’ve recognized the big challenges we’ve been facing in recent years. Plastics constitute a very new group of materials. It’s been roughly 120 years since they were invented. Compare that to other materials and we have several hundred years of gathering know-how and experience to catch up on. The technological and economic developments of recent decades have happened so quickly that our understanding has been unable to keep pace, especially regarding the need to deal with the products that have arisen. It’s not the material that’s the problem, it’s how we deal with the end product.

Are biobased, biodegradable, and compostable plastics the solution to the current plastic problem?

You have to make clear distinctions when you use these terms. Biobased plastics are plastics that are at least partially made from biomass, such as corn. They’re often non-biodegradable, however, or even non-compostable. Then there are biodegradable plastics, which are plastics that will decompose under certain conditions and only leave behind CO2 and water. But then, those plastics are often not biobased. Compostable plastics, which are another step up from biodegradable plastics, decompose particularly quickly under industrial-standard composting conditions. But that doesn’t mean they can be thrown onto a compost pile in the back yard. To do that, you often need special industrial composting plants, which, in turn, are worse for the carbon footprint.

So as you see, these groups of plastics are not bringing the salvation we were hoping for by automatically making plastics a sustainable class of materials. This is also reflected in the proportion of biobased plastics compared to overall plastic production, which as far as I know is something like one percent. Despite that, there are applications these types of plastics will become more important for, especially in the packaging area, where I see major potential. But what we mustn’t forget is that biobased plastics are made from corn, sugar, wheat, potatoes, plant fibers, and vegetable oils, so they compete directly with food and drink production, which raises other societal challenges.

Thinking about plastics recycling: It’s supposed to be good for resources and the environment, but it’s problematic when it comes to quality and costs. What can SMEs do to play their part in this area, yet still operate profitably?

You’ve touched on two key aspects of recycling. First, we need to find a way to produce materials “of high quality,” and that mainly means a high level of reproducibility when it comes to processing and material properties. Second, that process has to be economical. So that means there shouldn’t be any cheaper alternatives with the same material or product qualities. Getting those two things right is often a challenge for SMEs, and something that shouldn’t be underestimated. They usually have lower development capacities beyond the daily business. This is where we not only help companies analyze potential to make optimizations, but also show them how to implement recycling ideas.

Take the example of a classic plastics processing firm using injection molding to produce plastic parts for big companies. It already starts generating plastic waste when it produces those components, in the form of processing residues and rejects. That waste can be regranulated and put back into processing by mixing new granulates in defined proportions. That’s the most straightforward form of plastic recycling, since the processer knows the origins of the recycled material. But it still needs to check the mixing proportions of the regranulate so it doesn’t risk quality losses. It needs to convince its customers that reintroducing recycled materials doesn’t compromise the quality of components, and it must provide evidence of this through analysis. This also entails more effort carrying out quality checks in production, because material suppliers will only vouch for the quality of virgin granulate. In some cases, this additional effort alone is enough to make using regranulate economically unviable. And it becomes much more of an effort when you don’t know the origin of recycled materials, because the properties of every single batch have to be checked and you have to adapt the production process.

In summary I’d say that, from a technological standpoint, using recycled materials is possible in lots of areas of plastic production. But the cost advantages are currently so diminutive that they don’t always outweigh the heightened risk of substandard quality. With each rise in the price of plastic granulates, however, it becomes more likely that it’s worth using recycled plastics. We’ve worked on a number of successful projects with SMEs in recent years that involved using recycled materials.

Do you think there are any other forms of technology that offer a solution to the plastic problem?

I struggle with the idea that plastic is a problem, but I know what you mean. The way I see it, it’s not a problem with the technology we have but a problem with organization. So technologies alone can’t be the problem.

When you look at plastic products, there are so many parties involved in bringing products into circulation and using them – raw material producers, processers, product suppliers, customers, and users. But there are no clearly defined responsibilities when it comes to disposal or recycling. This is where we urgently need to create incentives so that plastic is given a relevant value as a material that you don’t just throw away.

Of course the deposit system for plastic bottles – and the dual system, which is better known as the Green Dot – mean that in Germany around 90% of plastic packaging is recovered. But of that, only between 50 and 60% ends up being recycled. The rest is mainly thermally processed – i.e. incinerated. In technological terms, we’re able to recycle a lot more plastic waste, it’s just unfortunate that the cost of doing so is too high; it’s more economical to process waste for energy purposes.

As for the technology you need to deal correctly with plastics, from an engineering perspective there are already many ways to treat plastic as a valuable material and save resources. Technologies are being developed on a continual basis under the umbrella term “lightweight construction,” and they help us use as little material as possible to do what we need to. Physical and chemical recycling is constantly being redeveloped in order to improve the quality and cut the cost of recycled materials. And there are some interesting ideas that involve using RFID and blockchain technology to enable plastic products to be traced, and this makes recycling easier outside the packaging industry. To do this, we need shrewd and switched-on people with the will to take on these tasks and challenges.


Prof. Dr.-Ing. Sven Friedrich (interviewee)
Steinbeis Entrepreneur
Steinbeis Innovation Center Engineering and Technology (Dresden)