Green Chemistry is making great leaps and bounds in the area of plastics. Plastics are ubiquitous in our everyday life – we can scarcely imagine life without them. However, the preparation and processing of plastics is a nasty, environmentally-messy process that generates vast amounts of toxic chemical waste. Since disposing of this waste is a money sink for plastic-producing chemical companies, researchers are beginning to develop plastics that don’t require the use of petrochemicals – an important first step in reducing the amount of waste produced.
One popular source of raw material (totally in keeping with the philosophies of Green Chemistry) are biorenewable sources of feedstock. Netherlands researchers have discovered a method to make plastics from potato starch, putting it to use in the areas of plastic cutlery and packaging. Their work has been mimicked by Chinese companies, who also use corn starch to similar effect.
Poly(lactic acid), or PLA, also has great promise. Lactic acid is ultimately derived from milk, and has a wide range of properties. A close competitor is PHA, of polyhydroxyalkanoates (made by bacterial fermentation of sugar). PHA has better physical properties, but it consumes more petrochemicals in its processing – a Faustian tradeoff. Also, making it in large quantities would require vast amounts of corn, which would probably require genetic modification of corn crops to keep up with demand. This opens up a whole new can of worms, and is pushing PHA out of the limelight, as noone wants to touch that subject just yet.
In a stunning piece of applied research, an American professor (Richard Wool) has used soybeans and chicken feathers to make computer circuit boards. The new boards are stronger and cheaper than traditional materials and since the traditional green plastic circuit boards represent most of a discarded computers waste, this is an area to watch in the future.
As one final example, researchers at Cornell have developed a polystyrene substitute that is made out of carbon dioxide and *orange peels*. A startup company is beginning to commercialize the process, calling the plastic PLC (polylimonene carbonate). Is this at least a partial answer to the vast amounts of CO2 that mankind has spewed into the atmosphere? Researchers are cautiously optimistic, but in the days of doom and gloom concerning greenhouse gases and global warming, surely every molecule of carbon dioxide counts!.