Bioplastics: A Sustainable Alternative to Car Interior

Since its inception, the automotive industry has failed to include sustainable practices in its production cycle. Traditional assembly lines and manufacturing processes many of which are still in use today use huge amount of energy, metals, plastics, toxins, and manpower; leaving behind a massive carbon footprint. The automobile industry is one of the biggest producers of commercial waste that degrades the environment’s quality. Not only during its production but even after its end of life tremendous amount of plastic waste is generated mainly from the automotive interior which is not recycled and ends up in landfills, water bodies, or in air polluting the environment. To overcome this, government policies, rising awareness among consumers & investors are now pushing automotive organizations to change their ways of working, culture, and products and make their vehicles more sustainable.

Biodegradable Plastics: Potential Solutions to Achieve Sustainability

Green Manufacturing

Green manufacturing is the renewal of production processes and the establishment of environmentally friendly operations within the manufacturing field. It aims to minimize production waste and the environmental impact of vehicle production by adapting product designs, manufacturing processes, and workflow principles to more environmentally friendly standards. One key area for sustainable automotive is the use of Bioplastics for interiors.

Volkswagen Group is switching its on-site coal power station at its Wolfsburg factory to natural gas and steam turbines.

Mercedes aims to construct a hydrogen-powered steel mill to supply carbon-free steel to the automotive sector.

Metal Recycling

Steel and iron components comprise around 65% of the average vehicle weight. Steel is 100% recyclable and can be recycled any number of times without losing quality. However, composite materials made of carbon and glass fibers and components made of alloys are difficult to recycle.

Alternate Sources of Energy

Using alternative fuel sources and transitioning to EVs is key to reaching net-zero targets. By 2035, the largest automotive market will be fully electric, providing a glimpse of a green future and significant economic opportunity. Renewable energy sources are also being explored to power the manufacturing and assembly lines, in addition to using them for battery charging.

Biodegradable Materials

The automotive industry is innovating new materials to replace environmentally harmful products during its production and disposal. Currently, most automotive interior parts are made of petroleum-based plastics, which pollute the environment during manufacture and disposal. An alternative is using polymeric compounds derived from biological sources, which generate a low carbon footprint, limiting environmental pollution and waste management problems. It is easy to dispose of after its useful life.

Biodegradable Plastics: Current Challenges with End-of-Life Vehicle

By replacing metals with plastics, the vehicle’s overall weight is reduced, resulting in a 3% to 7% increase in fuel efficiency. However, this increased use of plastics shifts the environmental burden from the vehicle’s use phase emissions reduction to the end-of-life vehicle (ELV) stage (materials disposal).

On ELV, the remains of the automotive interior are shredded for recycling and disposal. Most of the metal material and some amount of segregated plastic material is subjected to recycling. The remaining plastic material is known as shredder residue and ends in landfills. The shredder residue contains hazardous chemicals like lead, cadmium, polychlorinated biphenyls (PCBs), etc. As the use of plastic material increases, so does the amount of shredder residue, which causes pollution.

Hence, using biodegradable material seems to be a promising solution to overcome the pollution caused by unattended and landfill plastic.

Bioplastics for Vehicle

Bioplastics are biodegradable polymeric materials that can be recycled and readily decomposed when they end up in landfills. These can be used to replace conventional petrochemical plastics and are considered superior polymers compared to synthetic plastics due to their biocompatibility, making them exceptional for automobile applications. Bioplastics can be starch-based, cellulose-based, protein-based, lipid-based biopolymers, etc.

Some of the major bioplastics and their application in various automobile components is mentioned below:

• Bio-polyamides (Bio-PA): Bio-polyamides are derived from renewable resources such as natural fats and oils. They exhibit a good coefficient of friction, high wear resistance, increased temperature resistance, and impact properties and can be used for automotive applications. Castor oil is used to create the first Bio-PA, known as Rilsan PA 11, used in the automotive industry. It can be used to make connectors, brake noses, gasoline lines, and flexible tubing. Toyota is using DuPont Zytel, a blend of nylon resin components in their Camrys and Denso radiation end tanks.

• Polylactic Acid (PLA): It is a biodegradable hydrolyzable aliphatic semi-crystalline polyester. It is a relatively new bioplastic used in the automotive sector, previously used in the biomedical industry. Mats, carpeting, and upholstery are vehicle interior components ideally suited for PLA use. PLA is also employed in a variety of under-the-hood components.

• Bio-based polypropylene (Bio-PP): It is a polymer manufactured from natural materials such as corn, sugar cane, vegetable oil, and other biomass. It can be used to produce bumpers, spoilers, dashboards, air conditioning, battery covers, and air ducts.

OEMs’ Using Biodegradable Material

Mercedes-Benz

• Bio-based plastic derived from household waste – Mercedes collaborated with start-up UBQ materials with expertise to develop bio-plastics from household waste. This plastic can be used to replace petroleum-based plastic used in the injection molding process. Further, it can be foamed or used as a film for various automotive applications. Also, it is currently used as an admixture in filaments for the 3D printing of prototypes.
• Mercedes-Benz used sustainable lightweight materials in the cabin of its Vision EQXX all-electric concept car.
• The door handle is composed of bio-steel fiber, which is stronger than steel and biodegradable.
• The floor mats are made of recyclable bamboo fiber.

Renault

• Durabio, a bioplastic developed by Mitsubishi Chemicals, is partially bio-based engineering plastic made from plant-based isosorbide. Compared to conventional engineering plastics, it is highly weather—and heat-resistant.
• Renault was the first European automaker to use Durabio for the outer mask of the speedometer-tachometer combo on the dashboard of its Clio car model. It can also be colored and mixed with pigment to create glossy and highly reflective surfaces.

Volvo

• Volvo promises to use 25% bioplastics in new cars manufactured after 2025
• These materials will be used to produce dashboards, floor mats, and seats for automobiles
• Bio-based materials are made from repurposed plastic bottles and corks

Hyundai Motor Group

• The Hyundai IONIQ 5- vehicle actively uses environmentally friendly and recyclable materials.
• Fabrics incorporating bio-PET yarns are generated from sugar cane and corn. They are used for interior ceiling finishing materials, seat coverings, floor mats, and floor carpets.

Conclusion

For decades, the automobile industry has been searching for sustainable materials for producing automotive interior components and not letting them end up in landfills. Multiple alternate materials were tried and tested. However, most failed due to their high cost or undesired material properties. Bioplastics are breakthrough research that can potentially replace most of the 20,000 components made of petroleum plastic currently used in cars. It is cost-effective, has the desired properties for manufacturing, and can retain its shape and size until the end of its life.

Currently, bioplastics are being derived from carbohydrate-rich plants, such as corn or sugar cane, as it is the most effective feedstock for manufacturing. It ensures the highest yields and needs the least land area to grow. Moreover, research is being conducted on cascading feedstock utilization, focusing on using non-edible waste and by-products as feedstock for producing bioplastics. Furthermore, bioplastics have a promising future for automotive interiors, provided the companies can address the scalability issue and meet the high demands.