The fact that you can recycle thermoplastic composites was successfully researched 30 years ago, but until more than a year ago no one actually started doing it. Thermoplastic composites used in the aircraft industry, among others, are relatively expensive to produce and the waste stream of residual material is only increasing. Enough reasons for Hans and Winand to not only investigate this further, but to actually start recycling this extremely strong and valuable material.

After an initial feasibility study, Hans and Winand stepped in with their ideas more than six months ago at the ThermoPlastic Composites Research Center TPRC at Kennispark to rent office and workshop space. After a few months, the workshop turned out to be too small and besides, the shredding process used to grind the residual material into small pieces is not soundless. 

Shelter Technology Base symbolizes reuse

Through Oost NL they were alerted to Technology Base and it just so happened that shelter B534 was temporarily available and they were able to move in quickly. The first thing you notice when you enter the shelter at Technology Base are the large bags with pieces of plastic lined up in a long row. Winand: "This is the residual material left over from the production of so-called clips and cleats, structural parts used to assemble aircraft fuselages for Airbus and Boeing, among others. These thermoplastic composites are lightweight, strong, stiff and meet very strict safety requirements in terms of chemical and fire resistance. Partly because of this, they are difficult to dispose of as waste. In the absence of an alternative, in most cases the residual material is now incinerated at a high temperature. Besides the fact that this generates a lot of extra CO2 emissions, it is also a waste because the material can still be used for other applications. You can think of technical components in mechanical engineering, such as valves, compressor blades and bearings. Due to its high chemical and fire resistance, the material is also very suitable for automotive applications. 

The great thing about our shelter at Technology Base is that here, too, reuse by giving the building a different function is central. That fits perfectly with what we do here. Within the aircraft industry, the so-called R-ladder for circular entrepreneurship is very important and 'Re-purposing' is high on this ladder. We have therefore already heard from several stakeholders that the reuse of the aircraft-related shelter really appeals to them and is appreciated."

Hans: "Another big advantage is the space we have here to dispose of all the residual material, but especially the ability to be able to turn on the shredder all day without bothering our 'roommates'."

Best of two top working locations

Winand: "With our office we will stay with TPRC at Kennispark, because we can use the facilities and knowledge there. The University of Twente and also Saxion's ThermoPlastic Composites Application Center (TPAC) are closely involved with the TPRC, so we also have access to their network, knowledge and expertise. With Novel-T we went through the INNOVATE GO program and through them we got in touch with several companies. Initially, that was mainly for ourselves to gauge what needs there are and to see if recycled thermoplastic composite can be a more sustainable replacement for metal parts, for example, in the future, but also to make them aware that there are much more sustainable alternatives to the materials they are currently using."

Hans: "At Technology Base we can make use of the knowledge and expertise as well as the residual materials of AELS, which dismantles aircraft and reuses the parts as much as possible. For example, we currently have a number of air conditioning tubes from a Boeing dismantled by AELS. These tubes are also composed of thermoplastic composite and, in addition, a shell of high-quality insulation material. These tubes are difficult to recycle in this capacity by AELS, but we see a challenge in this and are going to find out if we can recycle both the composite and the insulation material. AELS also strives for full recyclability of aircraft and this way we can jointly achieve this goal. Our composite recyclate is not only strong but also light, which makes it ideal for building drones. With the drone innovation cluster Space53 and the test facilities of Twente Airport, we therefore see a nice potential collaboration to jointly develop and test more sustainable unmanned systems."

Circular chain project

Winand: "We find cooperation with other parties very important anyway. Our preference is for parties in the region, but in a Circular Chain Project in which we participate, we look beyond the regional borders and focus on the eastern Netherlands. With Impulse from the Achterhoek, we have developed a pump housing for well drainage pumps from our recycled thermoplastic composite. The residual material we ground into pieces was processed by The Compound Company in Enschede into injection-molded granules, from which AKF casts a casing syringe. This is a cheaper and lighter solution. The great advantage of our thermoplastic composite is that even after recycling it is still very strong and can be easily processed into any desired shape. The material has a long lifespan and can be recycled several times. That makes it a very durable and widely applicable material."

Future plans Spiral

Winand: "We feel that we are only at the beginning of fully recycling thermoplastic composites. We are now using the residual material from aircraft new construction, but in 30 years these parts themselves will also come back, and how nice it would be if these, along with all the other thermoplastic composites used in aircraft, came to us via AELS. We can then reuse them for applications in entirely different industries and for parts for which, for example, metal is still being used today. Composites are also used for bicycle frames, among other things, so here too we are looking at whether we can recycle them completely instead of burning them. In addition, we want to investigate how we can better preserve the high-strength properties of the thermoplastic composites used in aircraft. In the original materials, the fibers are long and lay neatly next to each other, which is what makes the material so strong and stiff. By cutting the material into pieces and eventually turning it into even small balls, the fibers also become smaller and lose some of their strong properties. If we are able to reuse larger pieces, we can develop an even stronger material and use this sustainable alternative for even more applications."