Thermoplastic Composites Taking-off into a Clearer Future

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The use of composite materials in orthopaedics is rapidly increasing, with the market estimated to reach USD 286 million in 2024 and grow at a CAGR of over 5% to cross USD 385 million by 2030.

August 12,2024

In early 2024, production of the world�s largest thermoplastic composite aircraft fuselage segment was successfully completed by welding two 8-meter-long CFRP (Carbon fiber reinforced plastics) half-shelf. This feat was achieved under the aegis of EU-funded Clean Sky 2/Clean Aviation project �Large Passenger Aircraft� (LPA) by the Fraunhofer- Gesellschaft in Stade, Germany, together with international project partners, which joined together a true-to-scale upper and lower shell of the �Multi-Functional Fuselage Demonstrator� (�MFFD�) using automated positioning and joining processes.

The almost rivet-less structure and the automated pre-integration resulted in 10% savings on each, weight, and cost.

Another interesting EU-funded project is the DOMMINIO project (Digital Method for Improved Manufacturing of Next-generation MultIfuNctIOnal airframe parts) which aims to demonstrate technologies enabling multifunctional, intelligent airframe parts that would also have benefits in repair and recycling at the end of life (EOL). The project bets on thermoplastic composites using Toray Advanced Composites TC 1225 unidirectional (UD) tape comprising carbon fiber and LM PAEK polymer by Victrex.

There are more such projects where prominent companies in the aerospace and composites industries have joined forces to promote thermoplastic composites and bring them into the mainstream.

Known for its demanding requirements, the aerospace industry has driven significant advancements in material science. In recent years, the spotlight has turned to thermoplastic composites (TPCs), a material class that has the potential to revolutionize the way we approach aircraft system design.

The Impressive Story of Composites in Aerospace & Defense (A&D)

Composites have had an incredible story from being just 4% in 1970s to having more than 50% share in structural weight now. From A300 to A350XWB for Airbus, and from 757/767 to 787 for Boeing, the composites usage has taken a big leap, now accounting for 53% of the material mix of A350XWB and 50% of 787. (Check Figure.1. for composites usage trends in different aircraft programs)

The usage of composites in aircraft, however, can be traced back to the World War I & II eras with notable examples like �the flying boat� and �the Mistel (mistletoe)�. However, specific details on the type and quantity of composites used in these aircraft are limited.

It was also noted that Glass fiber reinforced plastic (GFRP) was the composite structural material used in a wide range of aircraft and missile applications between the 1940s and 1960s. According to the Defense Technical Information Center (DTIC), the A-1E was the first production aircraft to incorporate composite GFRP. Grumman Aircraft produced fiberglass vertical tail structures for this military aircraft. This occurred during the mid-1960s when another breakthrough - �Boron fiber reinforcement� was introduced to the A & D industry.

During the 1970s, metals like aluminum, steel, and titanium dominated the aerospace manufacturing industry, comprising ~70% of the average aircraft�s structure. In contrast, the share of composites was infinitesimal, accounting for just 4% of materials used in aircraft manufacturing.

The benefits of composites were numerous, and impressive, but there wasn�t any rush in adapting composites in this industry. Gradually, after a lot of research and analyzing the long-term benefits of composites, the industry embarked upon the usage of composite materials.

In the early 2000s, the Boeing 787 Dreamliner broke new ground as the world�s first major commercial airliner to feature a primary airframe constructed from composite material. The aircraft is notable for its extensive use of composite materials, comprising ~80% of its volume and 50% (that is approximately 32,000 kgs of carbon fiber reinforced composite) of its total weight. Each Boeing 787 aircraft then used composites for wings, tails, doors, fuselage, and interior.

Not just Boeing, but other aviation giants like Bombardier, BAE systems, Raytheon, Lockheed Martin, and GE Aviation gradually jumped on the bandwagon of using composites in their aircraft.

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Figure1: Composites Usage Penetration Trend in Different Aircraft Programs

Evolution of Thermoplastic Composites

Throughout this transition, thermoset composites and autoclave processing have been the predominant choices for manufacturing aircraft components. Since the outset of this century, out of autoclave (OOA) processing techniques have begun attracting interest owing to the possibilities of faster production and lower fabrication costs, which is the industry�s priority. Owing to their properties, the surge in interest in OOA paved the way for the adoption of new materials - thermoplastic composites - which are well-suited to these processing methods.

Applications of thermoplastic composites date back to the US military�s F-22 jet fighter�s landing-gear and weapons-bay doors in the 1980s, and the outer wing trailing edge skin panel or shroud for the Fokker 50 passenger aircraft in the 1990s. (Check the evolution of TPCs in Figure.2.)

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Figure 2: Evolution of TPCs

Today, most of the modern aircraft feature thermoplastic composites in several applications, such as clips, cleats, fixed-wing leading edges, J-nose leading edges, panels for fuselage, profiles & brackets, ribs & angle brackets, control surface parts, seat backs, window panels, and cockpit floor.

Clips and cleats are considered to be the largest applications of thermoplastic composites in the industry and are made from carbon fibers with either PPS or PEEK resins. There are about 8,000 clips and cleats used in each A350XWB and about 10,000-15,000 clips and cleats in a B787 aircraft.

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Figure 3: Key Applications of Thermoplastic Composites in an Aircraft

Thermoplastics Vs Thermosets

Currently, thermoset composites dominate the A&D composites market; however, thermoplastic composites are successful in marking their presence in the structural sections of an aircraft by replacing both thermoset composites as well as traditional metals.

Unlike their thermoset counterparts, thermoplastics are capable of being reheated and reshaped repeatedly without losing their structural integrity. Known as thermoplasticity, this unique property enhances thermoplastic composites� recyclability.

Here�s a quick rundown of the differences between �thermosets� and �thermoplastics� -

Properties	Thermosets	Thermoplastics
Viscosity	Low	High
Chemical Resistance	High	Moderate
Toughness	Moderate	High
Age (Shelf life)	Moderate	Infinite
Reusability (Thermoformable)	Low	High
Cost	Medium	High
Melting Point	High	Low
Molecular Weight	High	Low
Overall Cost Savings	Low	High

Table 1: Property Comparison of Thermosets & Thermoplastics

Owing to their many benefits, thermoplastic composite materials in the A&D industry are witnessing an illustrious journey. Valued at US$ 330 million in 2023, the global aerospace thermoplastic composites industry is expected to reach US$ 870 million in 2030, growing at a skyrocketing annual growth of >14%.

It is important to note that the above figure represents only a fraction of the overall composite usage in the A&D industry. Despite the impressive growth, thermoplastic composites (TPCs) still account for merely 2% of total composites usage in the A&D industry which is around 34.5 million pounds.

Once considered unsafe for even structural components, TPCs are now being applied to critical control surfaces too.

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Figure 4: Thermoplastic Composites Contribution in the A&D Composites Market in 2023 (Volume)

Why are Thermoplastic Composites Industries New Favourites?

Now majorly being used in the A & D industry, thermoset composites have a major limitation, that is their inability to be re-melted, higher storage costs, longer curing times and shorter shelf-life.

Thermoplastic composites, on the contrary, offer all of these, while saving a lot of resources. They are even much tougher than their thermoset counterparts and are relatively insensitive to chemical exposure.

Thermoplastic composites offer several advantages over metals and thermoset composites, making them slowly but gradually gaining ground for aerospace applications.

Fast Manufacturing: Thermoplastic composites can significantly reduce manufacturing cycle times by as much as 80% compared to traditional materials. This is possible due to their ability to be molded and reshaped without curing. These materials can be recycled any number of times without even altering their chemical properties.
Superior Impact Resistance: Thermoplastic composites are known for their superior impact resistance and toughness, making them ideal for aerospace applications where components face bird strikes, foreign object damage, or hailstorms. This enhanced durability contributes to safer and more reliable aircraft structures.
High Strength/Weight Ratio: One of the key properties or say benefits of thermoplastic composites is their excellent combination of high strength and stiffness with low density, making it an ideal material of choice for applications where weight reduction is the main criteria. TPCs can decrease the weight of aerospace structures by as much as 50%.
Recyclability: The term �plastic� carries a burden, synonymous with environmental harm. Well, this is not the case with thermoplastic composites, since these plastics have lower landfill outputs. This is because thermoplastic components can easily be reformed and reused reducing the amount of wastage, and also it takes less energy to reform an already existing product into a new one, compared to manufacturing a new product from scratch.

Low Part Count: TPCs allow aircraft to be manufactured using fewer components or parts. How? Imagine a component being manufactured traditionally by fastening two or more parts together. Now, these TPC components can be designed as a single, integrated unit reducing the number of fasteners or assembly steps required, further reducing the weight and improving the aircraft�s �buy-to-fly� ratio.
Aesthetics: On one hand, where thermoset composites are deemed to have better aesthetics than metal alternatives, thermoplastic composites are seen as superior to them, due to their overall benefits.
Cost Saving: The non-porous nature of TPCs makes them less susceptible to dirt buildup or corrosion. This leads to a lower operational and maintenance cost and improved reliability for aircraft components.

These benefits position thermoplastic composites as a pivotal material in the evolution of aerospace design, enhancing performance, sustainability, and manufacturing efficiency in the A&D industry.

A&D Thermoplastic Composites Market from a Bird�s Eye View

Market Opportunity

According to Stratview Research�s report, in 2024, the global market for thermoplastic composites in A&D is expected to clock a revenue of USD 380 million generating a demand volume of 2.1 million lbs. By 2030, the market is expected to reach a figure of USD 870 million & a demand volume of 4.6 million lbs.

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Figure 5: Global A&D Thermoplastic Composites Market Forecast (2023-2030)

During 2024-2030, the A&D industry will generate a cumulative demand of ~27 million lbs. for thermoplastic composites equating to a sales opportunity of USD 5 billion.

Europe & North America, the Centers for Commercial Aviation, are the Largest Markets

Both North America and Europe are the innovation hubs of the aerospace industry. In North America, aircraft including Boeing 787 Dreamliner, Gulfstream Aerospace models like G500, G550, the F35 Lightning II fighter jet, etc. extensively use thermoplastic composites.

But the European region flies high on success contributing over 50% to the A&D thermoplastic composites market in terms of both value and volume. Europe houses major players like Daher, Dutch Thermoplastic Composites (now part of Collins Aerospace), and Premium AEROTEC GmbH, and supplies TPC components to aircraft like A350XWB, A320 + A330 Families. Another notable fact is that Airbus deliveries outpaced that of Boeing, securing the top spot and ultimately fueling the European market.

Carbon Fiber Composites Catering the Most of the Demand

Thermoplastic composites in the aerospace industry are used in the form of laminates, uni-directional tape, and fabric prepreg. polyphenylene sulfide (PPS), Polyetheretherketone (PEEK), Polyetherketoneketone (PEKK), and Polyetherimide (PEI) are the major thermoplastic resins used with either glass fiber or carbon fiber or aramid fiber to manufacture composite parts.

Thermoplastics with carbon fiber reinforcement lead the way with all the modern aircraft programs increasingly adopting them in their structures. About 35 tons of carbon composites are used in each super-sized Airbus A380 and mid-sized B787. The content of carbon composites is even higher with 65 tons in A350XW.

Carbon fiber offers numerous advantages, such as excellent weight reduction, high strength-to-weight ratio, high tensile and compressive strength, low coefficient of thermal expansion, and high fatigue resistance, but at a very high cost. Glass fibers, which however lag in mechanical performance, outperform carbon fibers in the economy, which is the prime driver for their usage in those areas where high performance is not the biggest concern.

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Table 2: Application Mapping of Thermoplastic Composites

High Market Concentration

A&D thermoplastic composites has witnessed some rigorous activity with some noteworthy acquisitions contemplating the rising opportunity over the past decade. Daher has been one of the most active players acquiring AAA, Stuart Composites, Triumph Group's Florida facility, and KVE Composites in the past couple of years, significantly adding to its strength in the market. Other notable acquisitions include Collins Aerospace�s acquisition of Dutch Thermoplastics in 2021, and ACP�s acquisition of Triumph Group�s composites business which was renamed as Qarbon Aerospace in the same year.

In 2023, the top five players, namely GKN Aerospace, Premium AEROTEC GmbH, Daher, Collins Aerospace, and Avanco Group (XELIS), captured nearly 75% market share. Few other leading players include ATC Manufacturing, SEKISUI Aerospace, and Re:Build Cutting Dynamics.

Thermoplastic Composites - Cleared for Take-off

The aerospace industry accounts for 2% of global CO2 emissions, and the industry is committed to achieving net-zero emissions by 2050. The rising CO2 emissions have compelled airlines to retire their aging aircraft and replace them with more fuel-efficient models.

At the same time, global air travel has recovered with passengers having started to travel again for business and leisure trips. The 2024 figure for passenger departures is expected to surpass pre-covid levels (2019) of 4.5 billion passenger departures. This has catapulted the passenger load factor back to 82.6% which was seen in 2019.

As a result, the factories and assembly lines are jam-packed with handsome order books of OEMs. Let�s look at some delivery figures.

Commercial Aircraft deliveries are expected to rise from 1,405 in 2024 to 1,870 in 2030.
Regional Aircraft deliveries are expected to rise from 186 in 2024 to 275 in 2032.
Business Jet deliveries are expected to rise from 750 in 2024 to 826 in 2032.

Similarly exciting are the forecast numbers put forth by commercial aviation conglomerates Boeing and Airbus with both suggesting a robust rise in fleet size from 24,500 & 22,800 in 2022 to 48,575 & 46,560 in 2042, respectively.

If we look at the order books, Boeing has 453 unfulfilled orders for the B777x, COMAC has more than 1,000 provisional orders for the C919, and Airbus has about 550+ orders and commitments for the A321 XLR. COMAC delivered its first C919 aircraft program to Chinese Eastern Airlines in December 2022, followed by another delivery in 2023.

This impressive orderbook is putting enormous pressure on the A&D industry to quickly ramp the production, amid the existing clouds of supply chain issues still hovering over the industry.

The industry is thus holding its expectations high on the thermoplastic composites as the plausible solution owing to its ability to produce parts in minutes compared to several hours with thermosets, recyclability and superior performance.

High cost is one of the biggest bottlenecks impeding the quick adoption of thermoplastic composites in aerospace industry. The price of a thermoplastic composite part is at least twice of the similar metal part which imposes a huge cost implication to the OEMs and tier players.

In addition, the industry has a long history of using traditional materials and it took 3 to 4 decades for thermoset composites to become the mainstream. Thermoplastic composites are comparatively newer and will need considerable demonstrations, education, and awareness.

However, recent advancements in technologies like AFP & 3D printing, and industry collaborations such as the MFFD project and their exciting results vouch for the long-term growth trajectory of thermoplastic composites.

The rising interest along with acceptance of the industry is undoubtedly the harbinger of a future clear sky for thermoplastic composites to take-off.