Nuria García Batista, Ph.D. at the Automotive Laboratory at AIMPLAS, the Plastics Technology Centre looks at their investigation in removing volatile substances from recycled polypropylene in vehicles.
Plastic is an important and ubiquitous material in our economy and daily lives. It has multiple functions that help tackle a number of the challenges facing our society. Light and innovative materials in cars or planes save fuel and cut CO2 emissions. High-performance insulation materials help us save on energy bills. In packaging, plastics help ensure food safety and reduce food waste.
Combined with 3D printing, bio-compatible plastic materials can save human lives by enabling medical innovation. The list goes on and on. However, too often, the way plastics are currently produced, used and discarded fails to capture the economic benefits of a more “circular” approach and harms the environment. For this reason, there is an urgent need to tackle the environmental problems that today cast a long shadow over the production, use and consumption of plastics.
Rethinking and improving the functioning of such a complex value chain requires efforts and greater cooperation by all its key players, from plastics producers to recyclers, retailers and consumers. It also calls for innovation and a shared vision to drive investment in the right direction. The plastics industry is essential to the European economy, and increasing its sustainability can bring new opportunities for innovation, competitiveness and job creation, in line with the objectives pursued by the renewed EU Industrial Policy Strategy. In December 2015, the Commission adopted an EU Action Plan for a circular economy. There, it identified plastics as a key priority and committed itself to “prepare a strategy addressing the challenges posed by plastics throughout the value chain and taking into account their entire life-cycle”. Also, in 2017, the Commission confirmed that it would focus on plastic production and use and would work to ensure that all plastic packaging is recyclable by 2030.
Within the European Strategy for Plastics in a Circular Economy, the Circular Plastics Alliance (CPA) was implemented in 2018 to help all players along the plastics value chain foster the use of recycled material with a commitment to boost the EU market for recycled plastics by 10 million tonnes by 2025. Working groups were therefore created between September 2019 and March 2020 to identify and confirm R&D needs and jointly prepare the CPA R&D programme, which includes increasing the use of chemical recycling on a wider range of plastics, using new technologies for mechanical recycling and preparing procedures to control the quality of recycled materials.
The automotive industry, one of the sectors that use the most plastic material and generates the most plastic waste, has signed an agreement with the CPA to reduce the amount of recycled plastic that ends up in landfills. If we look at the amount of waste generated by application in Spain (Figure 1), we can see that the automotive industry accounts for 4.7% of waste generated.
An R&D strategy is necessary to be able to use recycled plastic while maintaining quality and processability in all production steps and retaining the material’s mechanical properties.
Recycled plastic is currently being used in some automotive exterior components, such as wheel coatings (Chrysler), bumpers (Honda, Ford and Nissan) and radiator covers (General Motors), but it is being used in very few vehicle interior components. Most uses of recycled material inside the vehicle involve seat cushions made of recycled polyurethane foams (Chrysler) and upholstery fibres (Ford and Nissan)2. This reduced use can be explained by the fact that automotive manufacturers have to comply with very strict requirements in terms of volatile compound emissions and odours from plastic materials inside the vehicle. It is estimated that individuals spend approximately 5.5% of their day in a vehicle, where they can be exposed to contaminants from outside the vehicle (particles, CO2, nitrogen oxides and volatile organic compounds), as well as volatile organic compounds emitted by plastic parts inside the vehicle.
Different types of plastic can be found inside vehicles: PP, PVC, PA, PPE, PET, PBT, POM, PC, other thermoplastic materials and alloys. However, characteristics such as chemical resistance, mechanical properties, low density, abrasion resistance and cost make polypropylene the most used material for vehicle interiors (50% of plastics used inside vehicles are made of PP)3,4. The QOCTEL project will work on developing a technology that improves the recyclability and recovery of polypropylene plastic waste so it can be used to make parts and components for vehicle interiors. The main goal is to eliminate the volatile substances in recycled PP that currently cause it to produce unpleasant odours and prevent it from being reused for automotive interior components. This will make it possible to comply with the vehicle interior air quality requirements established by vehicle manufacturers.
An analysis methodology will also be developed that will involve using an emission chamber to analyse the decontaminated materials in more realistic conditions in terms of humidity, temperature and airflow in accordance with car manufacturer specifications.
This analysis methodology, as well as post-consumer PP decontamination, could be used in other sectors that require control of air quality and volatiles emitted by plastic materials.
1Key figures and data on plastics and plastic recycling in Spain, 2019 data, ANARPLA. Open figure 1 as PDF
3R. Sadiku, D. Ibrahim, O. Agboola, S. Owonubi, V. Fasiku, W. Kupolati, T. Jamiru, A. Eze, O. Adekomaya, K. Varaprasad, S. Agwuncha, A. Babulreddy, B. Manjula, B.O. Oboirien, C. Nkuna, M., Dludlu, O. Adeyeye, T. Osholana, G. Phiri, V. Ojijo, Automotive components composed of polyolefins. Polyolefin Fibres: Structure, Properties and Industrial Applications: Second Edition 2017, 449-496.
4K. Makenji, R. Cherrington, Plastic Trim, Materials and Manufacturing Polymers, Encyclopedia of Automotive Engineering, 2014.