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Issue 04/2019

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Biocomposites Biocomposites in the automotive industry Potential applications and benefits By: Blai López Rius Composites Department Researcher AIMPLAS Paterna, Valencia, Spain What is a biocomposite? Biocomposite materials can be defined as composite materials in which at least one of the constituents is derived from natural sources. This includes composite materials made from a combination of: • petroleum-derived polymers reinforced with natural fibres, • bioplastics reinforced with natural fibres, or • bioplastics reinforced with mineral or synthetic fibres (e.g. glass, carbon). Note that biocomposites are not necessarily biodegradable, as this depends on the matrix binding the fibre reinforcement. Only if the matrix consists of a biodegradable material – renewably-sourced or fossilbased, both are possible – will the biocomposite be biodegradable. Why biocomposites? The automotive industry will face a number of major challenges in the coming years. The first of these challenges is reducing greenhouse gas emissions (e.g. CO 2 ). The European Union, in conjunction with the European Automobile Manufacturers Association, enacted legislation aimed at reducing CO 2 emissions from light vehicles to 95 g/km by the year 2020 (Regulation (EU) 2019/631 [1]). Studies show that 80 % of the total emissions released from a vehicle during its lifetime are mainly due to the vehicle’s weight. A 100 kg reduction in car weight could provide a 0.3–0.5 l/100 km reduction in fuel consumption and a 7.5–12.5 g/km drop in carbon dioxide emissions [2]. The second challenge is petroleum depletion, as everyone should be aware by now. Oil resources are being consumed 100,000 times faster than nature’s ability to replace them, whereas products derived from plants have been underutilized. Oil reserves will decrease over the years and the law of supply and demand will drive up the prices of these raw materials, along with the end products derived from this source. Therefore, as the price of oil increases, renewable sources will become more attractive. A final point to consider is social pressure. In recent years, society has been calling for a change in consumer habits with the aim of taking more responsibility for the environment. This mentality is being transferred to the auto industry, which is faced with the challenge of trying to replace the current linear economic model with a circular one. A circular economic model starts with eco-design, Glove box - Hemp fibres and PP which takes into account the source of the raw materials for the items to be manufactured and how they will be reused in a new production cycle when they reach the end of their useful life. Biocomposite materials are positioned to become a potential solution for these challenges in the automotive industry. Biocomposites in the automotive industry Biocomposites have a number of benefits for use in automotive applications. Composites are generally lightweight materials, so they reduce vehicle consumption and greenhouse gas emissions. Compared to composites reinforced with fibres of non-renewable origin, biocomposites with natural fibres have excellent acoustic and thermal properties, making them ideal for vehicle interior parts. The use of these biobased materials improves working conditions, as the health risks involved in processing glass and carbon fibres are eliminated. Moreover, biobased materials do not require the highenergy processing of glass and carbon fibres, so less energy is consumed to manufacture them. However, the use of biocomposites in the automotive industry is not new. The first Model T by Henry Ford in the 1910s was made with hemp and ran on hemp-based fuel. Later on, in 1941, Henry Ford developed the first prototype composite car (the so-called “Plastic car”) made with soy resin and reinforced with hemp, sisal and wheat fibres [3]. 24 bioplastics MAGAZINE [04/19] Vol. 14

Biocomposites And in 1957, East Germany built the Trabant, a car featuring a unibody frame manufactured with a thermosetting phenolic resin reinforced with cotton [4]. Despite these examples, it was not until the mid-1990s that more intensive R&D work was carried out on this topic. Biocomposites now have many potential applications in the automotive sector. Their properties make them suitable for the manufacture of non-structural interior components, including wood trim, seat fillers, seat backs, headliners, interior panels, dashboards and thermoacoustic insulation. Car manufacturers such as Ford, Mercedes Benz, Toyota, Volkswagen and BMW are now using biocomposites in the interior components of some of their vehicles. However, this type of material is still under study and not yet commonly used to make structural parts. Biocomposites could also be used to make seat frames, load floors, pick-up beds, floor pans, and drivetrain and steering components. Many different biocomposites can be obtained by combining different reinforcements and matrices. The choice of these two components is determined by requirements in terms of the physical and chemical properties of the final parts and components. In the automotive industry, common natural reinforcements such as wood fibres can be used to obtain wood-plastic composites (WPC), and natural fibres from flax, hemp, jute and sisal can be used to produce natural fibre composites (NFC). However, the most commonly used reinforcement is flax fibre due to its good mechanical properties (specific strength comparable to glass fibres) and good availability. It is used for both short fibre and continuous long fibre. Thermoplastic and thermosetting matrices can be used in combination with these reinforcements. A number of thermoplastic matrix options are available: biodegradable polyesters (e.g. PLA, PHB, PBS), natural polymers (e.g. cellulose, natural rubber) and so-called drop-in bioplastics with up to 100 % biobased content (e.g. bio-PE, bio-PA, bio- PET, bio-PC, bio-PP). Many thermoplastic biopolymers are made via the fermentation of starch and glucose, others are for example made from bio-ethanol or isosorbide. Options in terms of thermosetting matrices include common resins with biobased content from natural oils and bioethanol (e.g. bio-epoxy, bio-polyester, bio-polyurethanes). Challenges and new developments However, despite the many advantages of biocomposites, serious challenges must still be faced and resolved before the use of this type of material can become more widespread. Current research is focused on optimizing the properties of raw materials to obtain balanced harvests with uniform Interior structure of a cars door - Hemp fibres and PE properties, developing the properties of the natural fibres used as reinforcement, improving compatibility between the reinforcement and matrix by taking into account natural fibres’ hydrophilic properties, reducing the flammability of natural fibres, and enhancing biocomposite recyclability. At the Plastics Technology Centre (AIMPLAS), different R&D projects on biocomposites with applications in the automotive industry have been developed and are currently under way at both European and national level to deal with these challenges. Examples include the completed FIBRAGEN and BIOAVANT projects, as well as KaRMA2020 and ECOxy, two European projects currently under development that form part of the Horizon 2020 program. The objective is to face these challenges by supplying the current market demand for cost-effective auto parts while helping create a more sustainable automotive industry. AIMPLAS is carrying out research on this topic to meet its commitment to environmental sustainability. As a result, companies from the sector will be able to integrate circular economy criteria into their business models and turn the legislative changes that affect them into opportunities to improve efficiency and profitability and reduce environmental impact. AIMPLAS also does research in areas such as recycling, biodegradable materials and products, and the use of biomass and CO 2 . References [1] REGULATION (EU) 2019/631 - Setting CO 2 emission performance standards for new passenger cars and for new light commercial vehicles and repealing Regulations (EC) No 443/2009 and (EU) No 510/2011 (2019). [2] Akampumuza, O., Wambua, P., Ahmed, A., Li, W., & Qin, X. (2016). Review of the applications of biocomposites in the automotive industry. Polymer Composites, 38(11), 2553-2569. doi: 10.1002/pc.23847. [3] N.N.: Ford’s Hemp powered Hemp made Car, cPCQM8 [4] Karner, R.: Go, Trabi Go! „Back to the future?“, bioplastics MAGAZINE, Vol 3, Issue 02/2008 B-pillar prototype - Hemp fibres and PP bioplastics MAGAZINE [04/19] Vol. 14 25

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