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Christian Bonten focuses mainly on bioplastics

Prof. Dr. Christian Bonten has been head of the Institute for Polymer Technology (IKT) at the University of Stuttgart since 1st September 2010. The former Institute for Plastics Testing and Science has recently become part of the IKT and has therefore come under Bonten’s area of responsibility. Bonton believes that bioplastics have great future potential and he plans to set milestones to drive bioplastics development forward. Bonton also focuses on the application of biocompatible plastics in the field of medical technology.

Bonten has had very specific objectives right from his initial appointment as head of the Institute for Polymer Technology. His aim is to restructure the institute and fully integrate the Institute for Plastics Testing and Science into the IKT by the end of 2010. In addition, the institutes, which are currently located in different districts of Stuttgart, will be combined under one roof within the next two years. The new IKT building is currently being renovated on the University of Stuttgart Vaihingen campus. It will initially be housed in an already existing building of around 2,500 square metres that will be renovated, and a second building will be available a while later. “Around 1.5 million euros will be invested in renovation and restructuring, and one million euros have been set aside for the IKT’s technical equipment. The IKT is the second largest plastics technology institute in Germany, and Germany is in fact the global leader in this field,” said Bonten.

Prof. Dr.-Ing. Christian Bonten is the new director of the Institute for Polymer Technology at the University of Stuttgart. © private

Bonten's CV clearly shows that he is quite keen on setting up new groups, teams and departments. He studied mechanical engineering in Duisburg and Aachen and specialised in plastics technology for a good period of time before being awarded his diploma degree. This comes as no surprise since Bonten's father held some patents in the field of polyamides and worked for Bayer in the same field. "My father's scientific work had a great influence on me and my brothers and sisters, and the natural sciences have always been part of our lives," said Bonten whose interest in plastics was further triggered by developments in the 1990s. "In the 1990s, it was discovered that using plastics rather than other materials led to much better resource savings, most particularly in the packaging market segment."

After doing his doctoral degree in 1998, Bonten accepted a position as senior engineer at an applied research institute associated with the University of Essen. In 2002, he accepted a position with BASF where he worked in the plastics application engineering department turning innovations into marketable commodities. He was also director of the "Universal Application Competence Centre" which is focused on the application of plastics in the field of medical technology before becoming responsible for the global marketing of two types of plastic used for medical applications. He developed new activities for BASF-Plastics in the Healthcare & Diagnostics market segment. He also realised that plastics were of great importance for designers and is regarded as the founder of BASF designfabrikTM, "where designers learn how to work successfully with plastics; they learn about product and tool design geared towards plastics. They are taught about special properties of certain plastics and also learn about the processing and manufacture of plastics products." In 2007, he was awarded the Dr. Richard Escales Prize for his commitment and achievements as well as his books and lectures that are all aimed at bridging the gap between designers and engineers. The prize is awarded every three years by VDI Kunststofftechnik and the Carl Hanser publishing house.

“Bioplastics have great future potential”

The Institute for Polymer Technology IKT at the University of Stuttgart is developing new plastics formulations using injection moulding compounders such as the one shown in the photo (Krauss Maffei IMC 200). © IKT

In 2008, Bonten joined the management team (assuming the role of authorised representative responsible for technology and marketing) of FkuR Kunststoff GmbH located in Willich close to Düsseldorf. The company was achieving an annual revenue growth of around 50%, and Bonten made a considerable contribution to this success. "The bioplastics market is growing between 20 to 30 per cent every year, and I think that this small company is the most innovative in this field in Europe," said Bonten. Despite his fascination for the bioplastics boom, he was nevertheless delighted with a professorship he was offered by the University of Stuttgart. In addition, he also looked forward to the prospect of shifting from industry to academia. However, he has never lost sight of research focusing on bioplastics and plastics for use in the field of medical technology. During his various posts in industry, Bonten kept up his teaching assignments at the University of Essen and the Karsruhe-based KIT. The move to Stuttgart and his acceptance of the post as head of the Institute for Polymer Technology was once again driven by his ability and flair for establishing new departments, teams and institutes. Of course, he will continue to keep tabs on FkuR's development - by maintaining a friendly professional relationship, as he calls it. He has dropped all contractual relationships with the small company in order to be able to concentrate fully on his new post, and to be able to remain neutral.

He plans to use his business know-how to help university spin-offs get off the ground and he hopes that his excellent team and ideas will help him in this endeavour. Bonten himself brings key detailed knowledge into his new position, something that is an important prerequisite for producing bioplastics with the relevant sought-after properties. "It is a great art to find the right mixture and material combination. The technical and mechanical properties of bioplastics are already very similar to those of traditional plastics. However, they have a greater water vapour and CO2 permeability, which makes them unsuitable for a number of applications," Bonten explains. He plans to reduce the permeability of bioplastics beverage bottles by coating and vaporising them with biological materials.

Bioplastics have already gained a great deal of ground in the packing industry. Bonten believes that this is due to the biological degradability of bioplastics, which also represents an additional disposal option. Bioplastics foils and bags can be composted and turned into biomass relatively quickly. The situation is slightly different for applications with a greater durability, for example mobile phone covers or computer keyboards. "In such cases, biological degradability is not important and not even required. The desire to avoid the use of petrol is one of Green IT's major selling points, whether this is achieved by energy-saving computers or computers that use less natural resources (bioplastics) to produce," said Bonten who also plans to come up with new bioplastics formulations for these areas.

Marketable bioplastics mixtures

Biological content wrapped in biological film – the Bio-Flex® A 4100CL flower wrapping is made of bioplastics and is certified for composting. © FKuR Kunststoff GmbH

New bioplastics mixtures are developed using processing extruders and special blending systems. The institute is already well equipped with such systems. "Biological plastics such as PLA and PHA have polymer chains with fewer side branches, which means that a PLA or PHA foil is not as tear-proof as foils made from other materials. This is why we have to use certain additives and let the mixture react in processing extruders. This gives the foil material an excellent, biaxial draw ratio and hence a biaxial stability," said Bonten. One of the institute's major challenges is to make different biological components compatible with each other. Crop starch and sugar beet supply important raw materials for raw bioplastics production. Starch and sugar beet are fermented, which results in lactic acid, which is subsequently polymerised into PLA (polylactic acid).

Bonten believes that PHA (polyhydroxyalkanoate) derivates, a substance that is biotechnologically produced with bacteria, is one of the most important, though underestimated bioplastics of the future. "PHA is suitable for injection moulding, which is important for products in the medical technology sector," said Bonten. "However, it is important to develop the right, pure additives and produce them in processing extruders." In general, plastics of high purity and uniformity are required in the medical technology sector. This is why it is necessary to use as few additions as possible. And this is another challenge for Bonten's institute in the development of sustainable mixtures.

Further information:

University of Stuttgart
Institute for Polymer Technology
Prof. Dr.-Ing. Christian Bonten
Pfaffenwaldring 32
70569 Stuttgart
Tel.: +49 (0)711 685-62639
E-mail: christian.bonten@ikt.uni-stuttgart.de

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