When autocars and motorwagens first appeared, they were full of renewable materials such as wood and leather, and Rudolph Diesel’s first eponymous engine ran on peanut oil. These days the average car uses more than 100kg of plastics made from oil (although frequently pretending to be wood or leather), so it’s becoming increasingly urgent to find renewable replacements.
Chemical engineers in the automotive industries and at numerous universities have been working to create new plastics, fabric and foam from plants for a number of years, but their work has generally been regarded as ‘lunatic fringe’. Now, spiking oil prices, plus America’s sudden realization that reliance on foreign oil is not a good plan, have pushed the throttle on their work. In fact, they’ve been joined in their task by research departments of giant food processing companies such as Archer Daniels Midland and Cargill Dow, eager to establish new markets for their produce.
Ford has just announced that the seats of the 2008 Mustang will be made from 40% soy foam, developed over seven years with the help and encouragement of the United Soy Board.
Honda and Mazda have both shown ‘bio-fabrics’ in concept cars within the past year. (Strictly bio-synthetics, as we’ve had bio-fabrics such as cotton for a very long time.) Mazda’s is made from polylactic acid, or PLA; Honda’s fabric, called polytrimethylene terephthalate (PTT) is created made by fermenting corn. Toyota has introduced kenaf into the package trays and doors of a number of vehicles from the Corolla to the Lexus LS 460 and GM has replaced fiberglass with kenaf fibres in the headlining of the Trailblazer.
Mercedes has been working on its renewables project for 15 years and already uses abaca fibres in the A- and B- Class, and coconut husks bonded with natural latex in its seat cushions. The company also uses coke derived from olive stones as tank ventilation in the C-class.
As well as cutting costs, plant fibres can be used to reduce weight to increase fuel economy or performance. For example, the current Corvette uses a layer of balsa wood in its composite floor as a weight-saving measure. The current E-class door panels use a flax/sisal fibre mat embedded in an epoxy resin matrix as sound-deadening material and this is 20% lighter than the wood-fibre materials used by the previous generation.
Where resin reinforced with plant fibres are used to replace fiberglass parts, weight can be reduced by up to 30% and these parts have none of the health problems associated with the production of fibreglass. The downside is that the growth of fungi and bacteria in the fibres must be prevented without using harmful chemicals. Plants can also take in and store moisture, leading to fogging inside the car.
One of the most visible signs that bio-parts are becoming big business is Ontario Canada’s BioCar initiative. The province’s two major industries are automotive and farming, so the Ministry of Research and Innovation has made a smart move in handing over close to $6m Canadian dollars to this project to be run jointly by the universities of Toronto, Windsor, Guelph and Waterloo. This money has been matched by the universities plus automotive, agriculture, forestry and chemical industries, and altogether the project is worth almost $18 million. Big names from the automotive world involved in the project include Ford, Chrysler and Magna.
The aim is to make Ontario a leader in developing renewable, cost-effective technologies for the auto industry, and the four centres will work to reduce production costs, increase functionality and improve the performance of materials based on hemp, wheat, corn, soy beans and canola. Prof Michael Worswick, associate dean of research for University of Waterloo’s faculty of engineering says: “BioCar is a neat project in the sense that it’s taking agricultural products and processing those as polymer sources to develop plastics.”
Ford’s Polymer Science Department, a team of around 50 chemical engineers lead by Debbie Mielewski has been working on renewable parts for eight years, an her team produced the Model U concept in 2003. This car used soy-based foam in the seats and soy resin in the tailgate and it had corn-filled tyres. The seats and dash were covered with a biodegradable fabric woven from a corn-derived PLA biopolymer (made by Cargill Dow). It got a few sideways looks but, unlike most show cars which retire after a year, this one has been round the world twice and is still touring. Mielewski says: “It’s been really well received, and has generated a lot of interest.”
Her team was recently renamed the Materials and Nano Technology Department because it has widened its remit to include nano-materials from metals or montmorillinite clays. Could car panels one day be made from clay? Mielewski reckons so. She says: “Toyota demonstrated it about 20 years ago and everyone has been trying to do it ever since. The problem is distributing the nano particles evenly through the matrix. The particles are so small they would create a great surface texture.”
Her soy foam project began when the United Soy Board’s New Business team approached Ford seven years ago, looking for new uses for surplus crops. Their first attempts as producing soy foam were lumpy or crumbly and gave off a rank smell. They’ve now managed to get rid of the stench and create foam that matches all the existing properties of conventional foam including exacting comfort and ‘spring back’ requirements. Mielewski says: The whole game is to balance the gel and the bubbles being created. Too many and the bubbles explode, too few and it’s solid.”
Another problem the team is still working on is the speed of production. Because there’s an extra process involved compared with oil, modifying the soy bean molecules into polyols, the foam takes longer to make, and that means extra cost.
Another exciting area her team is working on is research into the use of biodegradable plastics called Polylactide materials or PLAs. These can decompose in about 90-180 days, but only if given the correct temperature and humidity and in the presence of the correct microbes, so we could eventually have compostable parts. Mielewski says: “The challenge is to get 10 years of durability before the part starts to decompose.” The first step will be to make biodegradable plastics to replace the current plastic wrapping materials used to protect new cars on their way to the dealership. Eventually biodegradable plastics could help reduce the ‘autofluff’, that is the lump of different plastics that cannot be recycled at the end of a car’s life. This is a growing concern in Europe as recycling regulations get ever tighter, and insiders believe the same regulations will eventually come into force in North America. Professor Larry Erickson of Ontario’s University of Guelph has been working with Ford on this project. He says: “If some of that plastic could be made to be biodegradable it’s a way to go.”
Volvo in Sweden has also been researching biodegradable parts. Renewable Materials Specialist Katarina Sundqvist says: “We tried it and it works. I love the idea you make parts from plants, then compost them to grow new parts, it’s the circle of life.” She also reckons composting could easily become part of the European recycling programme, although the parts would have to be chosen carefully. Those likely to become contaminated with oil or coolant could poison the compost. Sundqvist also reckons it would be more energy-efficient to burn these old parts for power rather than trying to make compost in a country with cold winters such as Sweden.
The idea of growing raw materials, which will sequester carbon dioxide as part of the process, and reduce our dependence on oil, sounds like an ideal solution to many problems. Nevertheless, there are some questions about how truly green the new ‘bio-economy’ will be. Car manufacture is not the only industry that will be feeling the pain of rising bills for oil-based foam and plastics. Ikea is producing a new decking chair made with wheat, straw and polypropylene and other furniture manufacturers and computer manufacturers will soon be looking for cheaper, greener plastics and foams.
Even though the EU and US currently produce surplus crops, questions of land use, water and fertilizer run-offs need to be carefully considered. Bio-diesel and E85 have already suffered bad press, being accused of raising food prices and causing deforestation.
Professor Erickson agrees that increased demand for crops could “have a major ecological impact”. He says: “ One of the angles we’re taking is that rather than growing the crop for that purpose, we’d use by-products of the crops already growing, such as the stalks of the wheat, straw or soy.
Toyota’s green guru in the US, Bill Reinhart, explains that in Japan, Toyota engineers are given a ‘green budget’, as well as a financial one, and they are required to look at the water, land-use and CO2 issues associated with any materials going into the company’s cars. He is concerned, however, that worldwide there are not enough experts in lifecycle analysis ready to examine this new industry and lay down a reliable framework for companies to work within. He says: “There’s declining enrollment in engineering schools and not enough lifecycle analysis classes. We need students who understand what sustainability means.”
Daimler AG has chosen to become involved with growing its new raw materials to be sure of their green credentials. The Abaca plant, which provides fibres for Mercedes to replace PVC for underfloor cladding and stone protection on the A- and B-Class, is a sort-of banana, which grows in the Philippines and as a direct result of Daimler using these fibres, the rare Filipino Tarsier (the world's smallest primate), has been brought back from the edge of localised extinction - because it lives in Abaca plants.
Daimler has worked with the Hohenheim University and the German Investment and Development Association (DEG) on a project to reforest an area with various plants under a canopy of trees. The abaca-banana bush grows here in its natural habitat, and its processing creates jobs for the local farmers.
So – just maybe – this is one opportunity for car manufacturers to help save the planet.
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