With an innovative research project, Hof University of Applied Sciences has declared war on one of the biggest annoyances for German motorists: marten damage. At the Institute for Applied Biopolymer Research (ibp) at Hof University of Applied Sciences, headed by Prof. Dr. Michael Nase, materials are currently being tried and tested in collaboration with automotive supplier UNIWELL Rohrsysteme GmbH & Co. KG that are supposed to withstand the bite of the common stone marten far better than current materials in commercially available hoses. The market for this is huge – as is the interest of the automotive industry, of course.
According to the major German insurers, martens cause around 60 million euros worth of damage to motor vehicles every year – in Germany alone. Each year, more than 200,000 cases are reported to the insurance companies, which pay for the marten damage caused. If David Krieg from Naila in Upper Franconia, who is in charge of the project, has his way, this immense balance of damage should be significantly reduced in the foreseeable future. To this end, Krieg and his colleague Rafael Erdmann are researching a truly effective solution to this common problem in the institute’s pilot plants and laboratories.
Cost-effective solutions sought
Their starting point is what so often falls victim to martens: the hoses of the engine’s interior. “Our goal is to develop hoses made of an inexpensive mass plastic, which on the one hand has the same properties as PVC and on the other offers better protection against marten biting.” Although PVC itself is basically very suitable for the production of such hoses due to its thermal and mechanical properties, it forms hydrogen chloride during recycling due to its chemical composition. Other plastics that are equally resistant to biting are currently too expensive for industrial use. So there is a gap in the market that needs to be filled.
Since July 2019, Krieg and his team have therefore now been mixing and modifying bulk plastics in order to achieve the desired result and make the parts installed in automobiles significantly more resistant while still providing a cost-effective solution.
Melting point as a challenge
In the meantime, more than 200 different samples from 35 material mixtures have been developed and tested. “We use the technique of radiation crosslinking to modify the materials, in other words, we irradiate them,” says Krieg. This is done against the backdrop of using as few additives and other substances as possible to change the properties of the plastics. Significant progress has already been made, but the melting point of the finished products, which is still too low, is the biggest hurdle to the industrial use of the solutions that have been found. By the end of the project in the middle of next year, however, a solution should have been found for this too, says an optimistic David Krieg.
Naturally, interest in the research results has been huge from the very beginning. Accordingly, the project is funded by the German Federation of Industrial Research Associations (AiF), an industry-supported network for the promotion of research, transfer and innovation in small and medium-sized enterprises.
The average marten’s teeth
What is impressive in any case is the meticulousness with which the young researchers worked to verify the success of their plastics research in a scientifically reliable way. In cooperation with the Oldenburg Biological Institute, we therefore determined the average marten bite and its bite force and built a bite test rig,” says Krieg with a smile. Milled from a bone-like material from dental technology, the marten’s bite is now attached to a suspension and bites – controlled by a computer – into the different hose variants.
How bite-resistant is bite-resistant?
But how many bites does a good hose have to withstand to be considered “marten-proof”? The Hof University of Applied Sciences is also trying to find the right answer to this question. For this reason, the hoses currently available on the market and found in most cars are also subjected to the marten bite. “This is how we find our reference value and can see whether our materials bring better properties,” says the young researcher.
Scaring away bugs with bitter substances
Of course, the company does not want to rely entirely on the material and its properties alone in the fight against marten damage. In addition to the improved bite properties of the hoses, they are to carry a marten-repellent layer on their surface in the future. “By means of a plasma treatment with aerosol-dissolved bitter substances, we would also like to create a deterrent effect for the marten that lasts for years,” says David Krieg.
At the Institute for Applied Biopolymer Research (ibp) at Hof University of Applied Sciences, everything is currently being done to make it as uncomfortable as possible for the nimble animals with the sharp teeth under the hoods of the Republic.