The recent high cost of petro-based feedstock and polymers coupled with advances in new technologies like biotechnology, nanotechnology, green chemistry and material science have set the pace rolling for the revival of bio-based materials. It was Henry Ford, who in the thirties, used up to 30 kgs of soybeans in paints, enamels and molded plastic parts in the Model T. Plant-based plastics were used to make glove box doors, gear shift knobs, horn buttons, accelerator pedals, distributor heads, interior trim, steering wheels, dashboards and body panels. Fibres from hemp, wood pulp, cotton, flax and ramie were used as plastic fillers and reinforcement material. Gradually, parts made out of the rapidly growing petro based plastics that were cheaper and better performing, gained a stronger foothold in the automotive industry. Now, automotive companies are making a major effort to reintroduce plant-based plastics as a way of reducing their reliance on foreign oil and improving their environmental footprint.
An improved exterior surface quality, high-strength, heat-resistant plastic (bioplastic) made of natural materials that can also be used for vehicle interior parts has been developed. An industry-government-academia joint research project in Japan along with Mazda Motor Corporation has unveiled the material. An automotive sector first, this new bioplastic is made from natural materials and is carbon neutral because of the reduced amounts of fossil fuels used to make it and the consequent lowered amount of carbon dioxide (CO2) emissions. This newly-developed bioplastic, made of 88% corn and 12% petroleum, is stronger - it has three times the shock impact resistance along with 25% higher heat resistance when compared to contemporary bioplastics used for items such as electrical appliances. In addition, it is made with a fermentation process that includes natural materials such as fermented starches and sugars which, compared with the process to make polypropylene, reduces energy use by 30%. In contrast to current petroleum-based polypropylene plastics, the new bioplastics also has comparatively higher rigidity, resulting in thinner molds and fewer materials used. These attributes hold great promise for better productivity in the mass production of vehicle parts, since parts manufacture frequently involves injection-molding equipment. Mainly using corn-based polylactic acids, Nishikawa Rubber Co. Ltd, Hiroshima and Kinki Universities focused their efforts on developing a new nucleating agent for crystallization and a compatibilizer compound to raise the strength and heat resistance of the new plastic, dramatically increasing the amount of applications for automobile manufacturing.
Work is underway to develop 100% petroleum-free automotive plastics to make cars totally compostable. Researchers at Ford are working on this concept, making decomposition one of the 3 main challenges to overcome. Other solutions sought by the team include less moisture absorption (since natural fiber-reinforced plastics are more likely to absorb moisture causing durability concerns), and odor problems. Despite those challenges, biobased/recycled materials are already being used in several Ford vehicles, such as :
Soy-based polyurethane foams on the seat cushions and seatbacks on the Ford Mustang, Expedition, F-150, Focus, Escape, Escape Hybrid, Mercury Mariner and Lincoln Navigator and Lincoln MKS.
Soy-foam headliner on the 2010 Ford Escape and Mercury Mariner.
Underbody systems, such as aerodynamic shields, splash shields and radiator air deflector shields, made from post-consumer recycled resins such as detergent bottles, tires and battery casings.
100% post industrial recycled yarns in seat fabrics on vehicles such as the Ford Escape. The 2010 Ford Fusion and Mercury Milan Hybrids feature 85% postindustrial yarns and 15% solution-dyed yarns.
Ford researchers are looking more at plastics, rubber, foam, film and fabric to develop alternative bio-based materials that are functional, durable, cost-effective, and decreases use of petroleum oil. Possibilities include replacing glass fibers with natural fiber reinforcements made from cellulose, soy protein, hemp fiber, flax fiber and other bio-based materials; and PLA bioplastics for vehicle carpeting, floor mats, upholstery, and nondurable auto applications such as protective wrappings used during vehicle manufacturing and transit. Among other areas, Ford is currently looking in to the following challenges:
• Moisture absorption: natural fibre-reinforced plastics are more likely to absorb moisture over time, causing functional and durability concerns
Odour: injection moulding at high temperatures with a natural fibre-reinforced plastic emits an undesirable odour
Decomposition: PLA is designed to decompose quickly, but researchers want to make sure it will last the lifetime of a vehicle before that decomposition process starts.
Toyota Motor Corp plans to replace 20% of the plastics used in their automobiles with bio-plastics by 2015, starting with interior parts. Currently, polypropylene, polyvinyl chloride, polyurethane and acrylonitrile butadiene styrene account for about 80% of the plastics used in their vehicles. In 2001, Toyota first produced a small concept car called the ES3 with a bioplastics body and interior components made from sweet potatoes and sugar cane. The company was the first to commercialize the use of bioplastics in 2003 when they made the spare tire cover and floor mat of the Raum out of a composite material made of starch-based polylactic acid and kenaf.