Cover-Story Vienna
Cover-Story Vienna schoolgirls develop home- compostable coffee capsules By Michael Thielen Avoid waste, save aluminium: Two students of the TGM Austrias biggest engineering college located in Vienna, developed a biobased material for coffee capsules that actually biodegrades well, even in the compost box at home. “We are very proud that it works,” says Samantha Onderka (19), graduate at the TGM. Together with Katharina Schleinzer (18), she observed how the novel coffee capsules in their self-made compost box disintegrated within a few weeks. “It’s great to see the capsules change and degrade.” Coffee capsules for espresso machines are a convenient thing, but they generate a lot of waste. A typical capsule is made of 1.13 grams of aluminium. Three cups of coffee a day create more than 1.2 kilograms of aluminium-waste in one year. The two students of the TGM therefore hurled themselves particularly eagerly at a diploma project in preparation for their matura (A-levels) that could make the world a little bit better: Gabriel-Chemie, an international company with headquarters in Gumpoldskirchen, Lower Austria, needs a new, environmentally friendly material for coffee capsules. Andreas Höllebauer, Head of Research at Gabriel-Chemie, explained the idea: “We are looking for a bioplastic for coffee capsules. The material should be of natural origin and demonstrably very easy to degrade, not only in industrial composting plants, but quite normally in the home and garden”. Gabriel-Chemie mainly produces colours and additives for plastics and is therefore interested in the subject of coffee capsules. “We have been working with the TGM for many years,” explained Höllebauer, “so it made sense to advertise this research task as a Matura project.” Katharina and Samantha added: Common bioplastic capsules are only compostable under industrial composting conditions (temperatures between 50 °C and 80 °C, humidity around 50 % and the right population of microorganisms) in corresponding plants. At the same time, legal regulations in certain regions (such as Austria or Germany) prohibit the disposal of coffee capsules via a composting plant. The capsules currently available on the market that we know of are also not really suitable for biodegradation in home composting, as degradation would take far too long without ideal conditions. However, we wanted to develop a material that could be composted in our own garden even under sub-optimal conditions. Plastic from nature Katharina and Samantha experimented with various mixtures based on natural, renewable raw materials. Bioplastics are often made from sugar, starch or biomass. However, the final result should be waterproof and easy to form. The girls tested seven different bioplastics, which they produced themselves from various ingredients. Which took a lot of patience. Although the TGM is equipped with a machine for this purpose, it is of course a laboratory device designed for small sample quantities and filled by the spoonful. “To produce five kilograms of each new material, we had to spoon granules into the hopper for hours,” sighed Katharina. The granules were mixed and melted until the new material flowed out of a die. “Then we tested extensively whether the material should meet certain criteria. The bioplastics had to pass a tensile test and a tensile impact test and of course also needed the right properties for processing”. Of seven mixtures, exactly one was left to be considered as a candidate. It consists of materials entirely made from renewable raw materials. Using a special 3D laser printer (stereolithography), the students designed and built a mould with which they could actually produce coffee capsules from their new material in a thermoforming process. End-of-life more important than production The most important thing about this invention is its end-oflife solution. Would the coffee capsules actually completely biodegrade in a normal compost heap? Samantha and Katharina built a compost box suitable for domestic use and threw their coffee capsules literally “on the dung”. The experiment was successful. In the course of the weeks up to their Matura exam the girls could observe and document how the capsules became ever smaller and smaller. “We have found a bioplastic that can solve the problem with coffee capsules in the long term,” says Samantha happily. Outlook The current discussion about resource-efficient use and the avoidance of waste from disposable products offers great potential for ecologically more sustainable materials that were previously not commercially competitive. The Austrian Eco-Label is currently being awarded to biodegradable biopolymers used in the packaging sector. The material solution developed within this project would qualify for this. In the meantime, the project also was praised with the Borealis Innovation Award 2018. And the project will be continued. TGM and Gabriel-Chemie want to take a closer look at the degradation mechanism and further refine the formulation. Further processing tests will also be carried out in addition to the previous work. www.tgm.ac.at www.gabriel-chemie.com 34 bioplastics MAGAZINE [04/18] Vol. 13
Cover-Story Industrial Solutions for Polymer Plants Polylactide Technology Uhde Inventa Fischer Polycondensation Technologies has expanded its product portfolio to include the innovative state-of-the-art PLAneo ® process for a sustainable polymer. The feedstock for our PLA process is lactic acid, which can be produced from local agricultural products containing starch or sugar. The application range of PLA is similar to that of polymers based on fossil resources as its physical properties can be tailored to meet packaging, textile and other requirements. www.uhde-inventa-fischer.com bioplastics MAGAZINE [04/18] Vol. 13 35
