Lenses made of lactic acid
An environmentally friendly plastic for optical applications: Headlights, lenses, reflectors, and light conductors could all be produced more sustainably in future thanks to the new development. Scientists at the University of Paderborn, the Hamm-Lippstadt University of Applied Sciences, and the Aachen-Maastricht Institute for Biobased Materials are currently busy researching environmentally-friendly plastic products made on a lactic acid basis. The aim is to offer an alternative to the petroleum-based plastic that is currently still the norm. “Unfortunately, sustainability is not yet a purchase argument for consumers. They expect it, of course, but are not willing to pay for it. That’s why we need sustainable, high-performance polymers whose technical properties are affordable. And this is where we come in with the PLANOM project,” says Prof. Gunnar Seide of Maastricht University. Polylactide, or polylactic acid, could offer a crucial advantage here: The material is entirely biodegradable but has very good application properties in the visible range of the electromagnetic spectrum, and can be produced in large volumes in a way that is both environmentally friendly and cost-effective: “Polylactide or polylactic acid is obtained from renewable raw materials and is produced during the fermentation of carbohydrates via so-called lactic acid fermentation. That’s something we’re familiar with from sauerkraut, for example,” explains Prof. Klaus Huber of Paderborn University’s Chemistry Department.
The current tests focus on using the new material in connection with LEDs, although there are still a few hurdles to overcome, as polylactide becomes soft at approximately 60 degrees Celsius, while LED-based lights reach temperatures of up to 80 degrees. Furthermore, from 60 degrees upwards crystals form that cloud the material. For the product to reach market maturity, crystal formation therefore needs to either be avoided or at least be controlled. The polylactide could then be integrated for the first time in sophisticated technical lighting applications, with the first strike being its use as a lens material in bicycle headlights. “In Lippstadt we are also using specially developed equipment to investigate the resistance of the polylactide developed in the project in relation to short-wave visible radiation,” says Prof. Jörg Meyer from the Hamm-Lippstadt University of Applied Sciences. As a result, the sustainable optical bioplastic should improve the competitive edge of lighting manufacturers and automotive suppliers alike. Also as part of the project, young scientists are being trained for industry and for research institutions. The project has received funded of around 885,000 euros from the Federal Ministry of Food and Agriculture (BMEL) as part of its “Renewable Resources” program. The material research is expected to yield initial results in late 2022.