Our life seems to be wrapped in plastic - everywhere we look we see it. Almost every product we buy is made of plastic or has a plastic component, or is wrapped in plastic; most of the food we eat and many of the liquids we drink come encased in plastic. It is difficult to imagine life without plastic. Yet traditional plastic ie petrochemical-based plastic, is made of a non-renewable resource, poses an enormous waste management problem and is toxic to humans and the environment. Bioplastics may provide a safe alternative.
Bioplastics are not as new as most people believe. Henry Ford successfully used plant based plastics in his Model T car in the 1930s. Plant-based plastics have changed considerably since then. Today, while plant-based plastics are not yet widespread – currently they account for less than one percent of all plastic produced – their market and use is steadily growing.
Traditionally manufactured plastics ie petrochemical-based plastics use a large amount of fossil fuel in their production and create a waste management nightmare. The UK alone produces enough plastics to fill the Royal Albert Hall three times each and every single day. Most traditional plastics last indefinitely, taking thousands of years to disintegrate. Recycling plastic is an option but it can cost more in energy terms than is used for virgin plastics production. Petrochemical-based plastics also have negative environmental impacts in their manufacture, and negative ecosystem and human health impacts in their manufacture, use and disposal.
Plant plastic could well be the answer to these problems. Some of the benefits of bioplastic includes its biodegradability, its non-toxicity; it could be independent from rising oil prices; and it could create an oil surplus for use in other areas. But current production and disposal does not come without its own environmental issues. Using GM processes to produce plastic in the form of polyhydroxybutyrate (PHB) has unknown impacts on the environment eg how easy is it to confine genetically modified plants in one area? Whilst it has been suggested that plastic-producing plants can be commercially grown on agricultural land the ecological ramifications for organisms that might feed on the engineered plants and ingest potentially lethal doses of plastics are causing some concerns. All plant-based plastics whether they be in the form of polylactide (PLA), polyhydroxyalkanoate (PHA) or (PHB) use considerable more fossil fuels than do petrochemical-based plastics, in the extraction of the plastic from the plant. Alternative energy sources have been found but these require infrastructure changes in energy production which are costly.
Although plant plastics are biodegradable, they require bacteria and oxygen to enable the biodegradation process to occur. Most plastics whether bioplastic or petroleum plastic end up in landfill. Landfill is notorious for not providing the right conditions for decomposition – waste is compressed and sealed under tonnes of soil, thus minimising oxygen and moisture, which are essential requirements for microbial decomposition. Composting facilities are better avenues for bioplastics and paper.
Japan is one of the world leaders in bioplastic manufacture. Demand for bioplastics in Japan rose from 4,000 tons in 2000 to 6,000 in 2001, and to 10,000 tons in 2003, with an anticipated growth to account for approximately 10 percent of plastic production within the 10 years.
Henry Ford's early use of plant plastics
Henry Ford carries out 'impact testing' on his plant plastic car. The axe bounced and there was no dent'.
Henry Ford's dream was for a car made from plant material and fuelled by plant material. Two decades of research followed. He was motivated by a desire to find a non-food use for agricultural surpluses, and to develop a non-petroleum fuel. In the 1910's he experimented using plant materials, including wheat, in car manufacturing. The 1915 Model T Ford had coil cases made from a wheat gluten resin reinforced with asbestos fibres.
In the 1920's he focussed on soy products, and his company was able to develop uses for soy oil in automobile paints and enamels, in rubber substitutes, and in the production of glycerol for shock absorbers. Henry Ford's was interested in converting soy meal, the residue after soy processing, into plastics. Soy meal is approximately 50% protein and 50% carbohydrate ie cellulose. The resin core of the plastic was made when soy meal reacted with formaldehyde to produce cross-linked protein, and for added strength and resistance to moisture, phenol or urea was co-condensed with the soy protein, resulting in a part phenol formaldehyde (or urea formaldehyde) and part cross-linked soy protein resin. Ford used cellulose fibres from hemp, wood pulp, cotton, flax and ramie to provide additional fibres as fillers – up to 50 – 60%.
These plant plastics were used for glove box doors, gear shift knobs, horn buttons, accelerator pedals, distributor heads, interior trim, steering wheels, dashboard panels and finally the entire plastic body. The plastic body withstood blows 10 times as great as steel could without denting. Ford's 'plastic' car weighed 2,300 pounds, which is approximately 2/3s the weight of a steel model of comparable size, and was economically a better alternative.
Copyright 2005
Last Updated April 2005
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