Composite Recycling Methods

Recycling CF/PEKK laminates without cutting fibers: glass-transition delamination. This is one of the few recycling concepts that actually preserves what makes continuous-fiber polymers valuable. Thermoset composites can only be recycled through 𝗺𝗮𝘁𝗿𝗶𝘅 𝗿𝗲𝗺𝗼𝘃𝗮𝗹 such as pyrolysis or solvolysis, which recovers fibers but destroys the original polymer. Thermoplastic composites offer more options, but in practice recycling still means 𝘀𝗵𝗿𝗲𝗱𝗱𝗶𝗻𝗴 𝗮𝗻𝗱 𝗿𝗲-𝗺𝗲𝗹𝘁𝗶𝗻𝗴, and shredding inevitably cuts fibers, destroying length and alignment and with it most of the mechanical value. 𝗧𝗵𝗲 𝗰𝗼𝗿𝗲 𝗶𝗱𝗲𝗮: 𝘂𝘀𝗲 𝗧𝗴 𝘁𝗼 𝗱𝗲𝗹𝗮𝗺𝗶𝗻𝗮𝘁𝗲, 𝗻𝗼𝘁 𝘀𝗵𝗿𝗲𝗱 PEKK has a 𝗴𝗹𝗮𝘀𝘀 𝘁𝗿𝗮𝗻𝘀𝗶𝘁𝗶𝗼𝗻 𝗮𝗿𝗼𝘂𝗻𝗱 𝟭𝟲𝟬 °𝗖. If a CF/PEKK laminate is heated 𝗮𝗯𝗼𝘃𝗲 𝗧𝗴 𝗯𝘂𝘁 𝗯𝗲𝗹𝗼𝘄 𝗺𝗲𝗹𝘁, the matrix becomes rubbery, interlaminar strength drops, and a wedge blade can 𝘀𝗽𝗹𝗶𝘁 𝗶𝗻𝘁𝗮𝗰𝘁 𝗽𝗹𝗶𝗲𝘀 instead of cutting fibers. In the reported tests, 𝟮 𝗺𝗺-𝘁𝗵𝗶𝗰𝗸 𝗨𝗗 𝗹𝗮𝗺𝗶𝗻𝗮𝘁𝗲𝘀 were heated for 𝟱 𝗺𝗶𝗻 𝗮𝘁 𝟮𝟲𝟬–𝟯𝟰𝟬 °𝗖 and delaminated using a simple 𝗿𝗼𝗹𝗹𝗲𝗿 + 𝘄𝗲𝗱𝗴𝗲 𝗱𝗲𝘃𝗶𝗰𝗲. • At 𝟮𝟲𝟬 °𝗖, the matrix stayed too brittle and plies fractured. • Above melt at ~𝟯𝟰𝟬 °𝗖, fiber alignment collapsed. • The effective window was 𝟮𝟴𝟬–𝟯𝟮𝟬 °𝗖, where plies delaminated cleanly with fibers intact. 𝗪𝗵𝗮𝘁 “𝗴𝗼𝗼𝗱” 𝗹𝗼𝗼𝗸𝘀 𝗹𝗶𝗸𝗲 The process recovered ~𝟬.𝟯𝟰 𝗺𝗺 𝗽𝗹𝗶𝗲𝘀 from a 𝟭𝟬-𝗽𝗹𝘆, 𝟮 𝗺𝗺 𝗹𝗮𝗺𝗶𝗻𝗮𝘁𝗲, comparable to prepreg thickness. After reconsolidation, property retention was high: • 𝗙𝗹𝗲𝘅𝘂𝗿𝗮𝗹 𝘀𝘁𝗿𝗲𝗻𝗴𝘁𝗵: 𝟴𝟴.𝟲𝟵–𝟵𝟬.𝟰𝟵% at 280–320 °C • 𝗙𝗹𝗲𝘅𝘂𝗿𝗮𝗹 𝗺𝗼𝗱𝘂𝗹𝘂𝘀: 𝟴𝟲.𝟳𝟮–𝟴𝟯.𝟳𝟯% • 𝗜𝗟𝗦𝗦: 𝟴𝟴.𝟭𝟭% at 280 °C Property retention tracks 𝗳𝗶𝗯𝗲𝗿 𝗮𝗹𝗶𝗴𝗻𝗺𝗲𝗻𝘁, not chemistry. 𝗣𝗿𝗼𝗰𝗲𝘀𝘀 𝗽𝗵𝘆𝘀𝗶𝗰𝘀, 𝗻𝗼𝘁 𝗷𝘂𝘀𝘁 𝗽𝗿𝗼𝗰𝗲𝘀𝘀 𝗳𝗹𝗼𝘄  The wedge does not cut fibers. It propagates a crack along softened interlaminar regions, driven by matrix tearing and interfacial debonding. SEM shows a clean initiation zone followed by controlled ply separation with minimal fiber damage. 𝗪𝗵𝗲𝗿𝗲 𝘁𝗵𝗶𝘀 𝗳𝗶𝘁𝘀  This approach sits between two extremes in thermoplastic composite recycling: 𝘀𝗵𝗿𝗲𝗱𝗱𝗶𝗻𝗴 that preserves material but destroys structure and 𝗰𝗼𝗺𝗽𝗼𝗻𝗲𝗻𝘁-𝗹𝗲𝘃𝗲𝗹 𝗿𝗲𝘂𝘀𝗲 𝗲𝘅𝗮𝗺𝗽𝗹𝗲𝘀 like the A380-to-A320 thermoplastic repurposing. The focus here is on 𝗽𝗿𝗲𝘀𝗲𝗿𝘃𝗶𝗻𝗴 𝗳𝗶𝗯𝗲𝗿 𝗰𝗼𝗻𝘁𝗶𝗻𝘂𝗶𝘁𝘆 𝗮𝗻𝗱 𝗮𝗿𝗰𝗵𝗶𝘁𝗲𝗰𝘁𝘂𝗿𝗲, 𝗻𝗼𝘁 𝗷𝘂𝘀𝘁 𝗺𝗮𝘁𝗲𝗿𝗶𝗮𝗹. If you work with thermoplastic composites, I would be interested to hear where you see the main bottleneck today: heating control, inspection of recovered plies, or reconsolidation and joining back into certified structures.

Wood Waste-derived Thermoset Plastic Catalyzes its own Degradation Process.   Epoxy resin thermosets (ERTs) represent an important category of polymeric materials renowned for their robustness and exceptional thermal resilience. They play an essential role in various critical industrial sectors, including packaging, composite manufacturing, transportation, construction, and aviation.   However, their inherent strength comes with a drawback—they are extremely challenging to break down or recycle. Additionally, epoxy-amine resins, often incorporate bisphenol A (BPA), known as an endocrine disruptor.   A recent Science paper reports the synthesis and closed-loop recycling of a fully lignocellulose-derived epoxy resin (DGF/MBCA) is achieved through a process involving the dimethyl ester of 2,5-furandicarboxylic acid (DMFD), 4,4′-methylenebis(cyclohexylamine) (MBCA), and glycidol.   This resin exhibits exceptional thermomechanical properties, including a glass transition temperature of 170°C and a storage modulus at 25°C of 1.2 gigapascals.   Notably, the material undergoes methanolysis without any catalyst, regenerating 90% of the original DMFD. The diamine MBCA and glycidol can then be reformed through acetolysis.   This work, coupled with promising commercial potential, represent a significant step towards incorporating thermosets into the circular and bio-based economy. #plasticpollution #bioplastics #sustainability Image credit: c&en, ACS

There is a cash cow of an opportunity for the companies that can figure out how to make new products out of repurposing wind turbine blades.  Challenges with repurposing the fiberglass blades have led to fields of retired blade graveyards and/or disposal in landfills.  According to NREL, an average of 5500 blades will be retired each year for the next 5 years in the US alone; that figure would increase between 10,000 and 20,000 until 2040. Can you say "Houston, we have a problem"?   Here are 3 US based companies that are figuring out solutions to reduce and repurpose this difficult material:   Carbon Rivers, Inc. This Tennessee-based company has developed a process to recover clean, mechanically intact glass fiber from decommissioned wind turbine blades. The recycled fiberglass is then upcycled into new composite materials, contributing to a circular wind turbine economy. Veolia North America: In partnership with GE Renewable Energy, Veolia processes decommissioned blades by shredding them and incorporating the fiberglass and resin into cement production. This method not only recycles the blade materials but also reduces CO₂ emissions in cement manufacturing by approximately 27%. REGEN Fiber Located in Fairfax, Iowa, Regen Fiber has established a facility capable of processing up to 30,000 tons of wind turbine blades annually. Their proprietary process recycles 100% of the blade materials into fibers and additives that enhance the durability and environmental resistance of concrete and asphalt.   In a country where the DOT loves to temporarily fill or resurface roadways with composites that can't withstand the wear/tear, I love the idea of resins being created that strengthen our building materials with repurposed materials from otherwise wasted products.    What other ways have you heard of these materials being re-purposed?

New generation of recyclable composites for wind blades: In 2023, Mingyang launched wind turbine blade made from recyclable materials. Siemens Gamesa developed  wind turbines with RecyclableBlades. Other companies work on other recyclable materials for blades, notably, vitrimers. Indeed, these new materials are recyclable. But how to recycle them in optimal way, to get high quality recycled products - which solvents, which temperature regimes? In our new article “Solvolysis of novel recyclable composites for next-generation wind turbine blades”, Dr. Yi Chen developed an advanced computational model of chemical recycling (solvolysis and depolymerization) for the new generation of composites based on recyclable thermoset polymer matrix.  The model incorporates realistic composite microstructures, including microscale defects such as manufacturing-induced voids, to examine their impact on the end-of-life recycling process, and can be a basis for the optimization of recycling technology. This work is a continuation of our previous works, “Modeling the solvolysis of composite materials of wind turbine blades” (https://lnkd.in/eHWtJFqF), “Multifield computational model of chemical recycling of polymer composites” (https://lnkd.in/e4zuV9Ga) and “How to repair the next generation of wind turbine blades”, (https://lnkd.in/eGhaAHdt). The works were carried out in the framework of WiseWind project (“WiseWind: NeW generatIon of SustainablE Wind turbine Blades”, https://wisewind.dtu.dk/). Link: https://lnkd.in/eW2q339a

Wind turbines have been powering a greener future for decades, but what happens when their blades reach the end of their lifespan? With over 43 million tons of turbine blades expected to be decommissioned by 2050, the question of sustainable disposal has never been more critical. Enter wind blade recycling—an innovation-packed solution transforming waste into opportunity. Here’s how blades are getting a second life: 🔹 Pyrolysis: This advanced process breaks down composite materials into reusable raw materials like fibers and resins, perfect for repurposing in other industries. 🔹 Grinding: Decommissioned blades are shredded into smaller pieces, which can then be used as fillers in concrete, asphalt, or other construction materials. 🔹 Repurposing: Creative solutions are turning blades into bridges, benches, playgrounds, and even art installations, showcasing the circular economy in action. The global wind blade recycling market is valued at USD 68,235 thousand in 2024 and is projected to reach USD 370,935 thousand by 2029, growing at 40.3% cagr from 2024 to 2029. Why does it matter? - Environmental Impact: Preventing blades from ending up in landfills helps reduce carbon footprints. - Economic Opportunity: Recycling creates jobs, sparks innovation, and opens new business models in the green economy. - Sustainability Leadership: For companies in wind energy, recycling is not just responsible—it’s a competitive advantage. The wind blade recycling market is booming, driven by cutting-edge technology and increasing pressure for sustainable solutions. #WindEnergy hashtag #CircularEconomy hashtag #WindBladeRecycling #Sustainability #Innovation

Wind Turbine Blade Disposal Were Supposed to Be the Price We Paid for Green Energy. That Equation Just Changed.   By 2050, 43 million metric tons of wind turbine blades will reach end-of-life. These aren’t biodegradable, nor are they easily recyclable. They’re made from hyper-durable composites—mostly glass or carbon fiber locked in a near-indestructible epoxy matrix. Until now, “recycling” meant landfilling, incineration, or grinding into low-value filler. In other words, not recycling at all. That’s the problem with high-performance composites: what makes them strong also makes them stubborn. But a Danish research team, in collaboration with Vestas, may have quietly changed the rules of the game. Instead of smashing composites apart, they used a biomimetic molecular trick: embedding a tiny dose of the amino acid cystine during epoxy curing. This introduces reversible cross-links—chemically engineered escape hatches. With a mild pH switch and common solvents, the matrix softens. The resin dissolves. The fibers emerge—fully intact. This isn’t incremental. This is chemical circularity—where end-of-life becomes a design parameter, not an afterthought. Why this matters to investors: 🧠 Defensibility: Embedding recyclability into the polymer backbone is a platform technology, not a patch. 🌍 Market Pull: OEMs are under pressure to deliver “zero-waste” wind energy. The EU, for instance, is already moving to ban blade landfilling. 📈 Scale: Composite waste isn’t just a wind problem—it’s aerospace, automotive, even consumer goods. Solving it opens a multi-billion-dollar materials recovery market. The thesis: Mechanical recycling is yesterday’s compromise. True circularity will come from programmable materials—where chemical structure encodes end-of-life behavior. And that unlocks a new category of climate tech: regenerative materials systems. I believe this shift creates enormous whitespace for deep tech investment. Not just in blade recycling—but in the reinvention of thermosets themselves. 🔍 I’m tracking this space closely and advising across materials startups. If you're an investor exploring new materials platforms, let’s talk.

What to do with recycling of mixed waste from end-of-life vehicles? Why not simply use it again?💡 In a pilot project we demonstrated the recyclability of high-performance plastics contained in the so-called automotive shredder residue – a mixture of shredded parts such as foams, plastics, films and paint particles, mainly from end-of-life vehicles. We have set the goal to promote the circular economy in the manufacturing of our vehicles and want to increase the proportion of recycled materials in its vehicles. And that is one way how to do it. So, what lays at the heart of the recycling project? ▪️ Gasification is a form of chemical recycling that can be used to convert mixed waste streams into valuable new raw materials, for example for plastics production. ▪️The pilot project serves to evaluate the potential of automotive shredder residue as a future source of recyclate. ▪️Advanced gasification technology is used to convert plastic waste into synthesis gas at high temperatures. ▪️Within the synthesis gas created at the production network of our partner BASF, new plastic is produced for component manufacturers. ▪️As part of the pilot project, the formulation was used for new steering wheels. ▪️The raw materials produced from gasification are of comparable quality to conventional raw materials. Without any doubt a complex task with a sophisticated recycling process. But it is more than worth the effort when it comes to our sustainability efforts at Porsche AG. For me it is simply a heartfelt wish …