With manufacturers focused on net zero goals, materials offering sustainability benefits through weight reduction or reduced carbon emissions are becoming more sought after across industry sectors
In the automotive industry, carbon fibre composites are exceptionally lightweight and have a high stiffness-to-weight ratio and tensile strength, which makes them durable and well suited for optimising vehicle performance. However, oil-based, energy-intensive manufacturing methods mean that carbon fibre also has a significant carbon footprint.
A NATURAL APPROACH
To reduce weight without compromising performance, some manufacturers in the automotive sector and its adjacent industries are turning to natural fibre composites (NFCs) instead. Made using plant fibres, such as hemp or flax, embedded within a polymer matrix, NFCs are emerging as a sustainable alternative for applications where extreme mechanical performance is not essential. As NFCs are essentially renewable and biodegradable, they typically have a lower carbon footprint and are often more cost-effective to produce than synthetic materials such as carbon fibre. In addition, many natural fibres, such as flax, are already byproducts of established agricultural industries, which further enhances their commercial appeal.
NFCs are strong enough for many non-structural and semi-structural applications, whilst remaining lightweight. In automotive manufacturing, reducing weight improves fuel efficiency and extends EV battery range, making lightweight materials increasingly valuable. Although NFCs are unlikely to replace carbon fibre at the upper echelons of performance motorsport, they are becoming increasingly viable for use in both structural and non-structural automotive parts, such as interior trim panels, dashboards, door panels and exterior bodywork, where components must remain durable and rigid, without being over-engineered. For example, in 2024, Volvo Car Corp filed a series of patent applications for automotive interior or exterior components formed of multiple layers of natural fiber fabrics embedded in a thermoplastic matrix material.
THE BENEFITS FOR MICROMOBILITY
NFCs are also gaining traction within the e-scooter and wider micromobility market. Much like cars, components for e-scooters need to be lightweight and strong, without having to withstand the extreme loads associated with high-performance automotive engineering. For e-scooter manufacturers, NFCs offer a sustainable and commercially viable alternative to traditional plastics or carbon fibre composites, whilst also helping manufacturers reduce reliance on synthetic materials.
As new reinforcement and treatment methods emerge on the market, NFCs are continuing to improve in terms of performance. For example, many NFCs are by nature prone to moisture absorption, and tend to offer limited fire resistance, which can restrict their suitability for certain automotive and outdoor applications. Innovative solutions that focus on improving their durability and safety performance through surface treatments or hybridisation techniques are therefore increasingly becoming a source of academic interest.
In a recent study by a group of research scientists in Bangladesh, a variety of different chemical treatments for JUCO and banana fibre mat composites were investigated, in which it was found that treatment with sodium chlorite (NaCIO2) was particularly effective in reducing water uptake. Meanwhile, silicone and boron-based surface treatments also provide promising avenues for improving the flame retardancy of NFCs without significantly impacting their mechanical or environmental properties.
MATERIAL MIX
Hybridisation is also gaining traction, combining natural fibres with materials such as glass or carbon to enhance barrier properties and mechanical performance, whilst keeping overall material weight and the use of synthetic materials to a minimum.
When it comes to automotive and e-scooter manufacturing, addressing moisture absorption and fire performance is essential for safety reasons. Many micromobility products, for example, are battery-powered and exposed to the elements, so manufacturers are increasingly exploring advanced surface treatments and flame-retardant technologies to improve long-term durability and safety.
Beyond the automotive and e-scooter sectors, there is also growing interest in NFCs in the aerospace industry, for instance, in the manufacture of cabin interiors or non-structural panels that are not primary load-bearing structures. The European Cayley project, which involved Boeing Research and Technology Europe, Invent, Aimplas and Lineo, developed flax-based interior panels and a full-scale 737 sidewall panel made from natural fibre reinforced composites, including flax, in either an inorganic thermoset or thermoplastic resin, treated with a fire-retardant to meet cabin fire safety requirements. Boeing has also filed several patent applications in this technology area.
As such, continued innovation in materials science is steadily expanding the range of applications where natural fibre composites can offer a practical engineering solution.
IP PROTECTION
For innovators developing and using NFCs for specific applications, there are plenty of opportunities to protect intellectual property – not only in the finished component itself, but also in the processes behind it. For example, surface treatments designed to reduce moisture absorption, flame-retardant formulations, hybridisation techniques and specialist manufacturing methods may all offer patentable innovation opportunities. Patenting developments on route to market can bring significant commercial benefits, including licensing opportunities and tax-relief via the Patent Box regime, at the same time as offering innovators a competitive advantage through exclusivity rights.
NFCs demonstrate that lightweight engineering and sustainability do not need to come at the expense of commercial viability or performance. Whilst there are some challenges around durability and performance, advanced surface treatments and hybridisation techniques are helping to adapt NFCs for mainstream automotive and micromobility applications. With mounting pressure to reduce weight and emissions further, NFCs can play an increasingly important role in sustainable transport solutions in the future.
