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 the combination of:
- petroleum-derived polymers reinforced with natural fibre,
- biopolymers reinforced with natural fibre, or
- biopolymers reinforced with synthetic fibre (e.g. glass, carbon).
The automotive industry will face a number of major challenges in the coming years at both European and global level.
The first of these challenges is reducing greenhouse gas emissions (e.g. CO2). The European Union, in conjunction with the European Automobile Manufacturers Association, enacted legislation aimed at reducing CO2 emissions from light vehicles to meet the target of 95 g/km by the year 2020.
The second challenge is petroleum depletion. Oil resources are being consumed 100,000 times faster than nature’s ability to replace them, whereas products derived from plants have been underutilized.
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.
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 of non-renewable origin, biocomposites have excellent acoustic and thermal properties, which makes them ideal for vehicle interior parts.
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.
However, this type of material is still under study and not yet commonly used to make structural parts.
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).
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 commodity polymers with bio-based content (e.g. bio-PE, bio-PP, bio-PET, bio-PC). Many of these thermoplastic biopolymers come from the fermentation of starch and glucose. Options in terms of thermosetting matrices include common resins with bio-based content from natural oils and bioethanol (e.g. bio-epoxy, bio-polyester, bio-polyurethanes).
Challenges and new developments
Current research is focused on optimizing the properties of raw material to obtain balanced harvests with uniform 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.
Source: AIMPLAS Blog, press release, 2019-10-16.
Author: Blai López Rius