Plastics Technology

MAY 2012

Plastics Technology - Dedicated to improving Plastics Processing.

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know-how materials mike sepe Biopolymers: Time to Take A Deep Breath The enthusiasm for polymers made from biologically derived materials is understand- able. After years of plastics being assailed by environmental groups, the media, and the general public for being "part of the problem" of consumption of fossil fuels, it undoubtedly feels good to be able to point to the growing sector of biopolymers as evidence that the plastics industry is acting in a conscientious and proactive manner. It is consistent with the ethic behind already worn-out terms such as green and sustainable. This newfound enthusiasm for a sector of the industry that seems to have finally reached critical mass after 35 years of painfully slow and uneven development has given rise to some bold and even outrageous predictions regarding the degree to which biopolymers will replace oil-derived plastics as this cen- tury unfolds. One online survey that was posted recently asked a question to the effect of, "How soon will biopolymers displace oil-based polymers as the dominant class of materials used in the plastics industry?" The multiple choice menu contained options like 10 years and 25 years. I checked "Never." Never is a long time, but my answer was motivated less by a belief that it can't happen than by a conviction that it should not happen, at least in its current incarnation. Deriving propanediol from grains or ethylene from sugar cane may sound like a good idea. However, this is an extension of the strategy that introduced alcohol derived from corn to the motor-fuel industry. This approach has contributed to a substan- tial increase in the price of food as the supply of staples has been reduced in favor of growing crops for fuel. This has gone largely unnoticed in Europe and the U.S., where the cost of food does not constitute the percentage of the family budget that it does in developing nations. But it has had a large impact on the ability of large segments of the world's population to feed itself. There are some inescapable facts to be confronted about the state of food production in the world today and the growing problem of feeding a rapidly expanding population. And it begins with the fact that approximately 1 billion of the 7 billion inhabit- ants on the planet already suffer from chronic hunger. This is a conservative estimate; some place the number closer to 2 billion. Add to this the projection that by 2050 we will add another 2 billion to 3 billion people, and that those already living or yet to 26 MAY 2012 PLASTICS TECHNOLOGY The author argues that large-scale use of food crops—or land that could be used to cultivate them—to produce biopolymers would raise concerns about global food sup- plies, water use, and the environmental effects of agricul- ture. A more sustainable solution, he argues, would be use of inedible plant matter, preferably grown on land not suitable for food production. (Photo: RTP Co.) be born into countries with rapidly developing economies will consume more food, and the best estimates indicate that world food production will need to double in the next 40 years. It is not entirely clear that this is an attainable objective given the fractured nature of the world political system. However, it is clear that one thing that is not needed to add further to the burden of meeting this objective is diverting large amounts of food crops to production of polymers. As things stand, only 60% of the food grown today ends up going directly to human consumption. An additional 35% is used for animal feed. It takes 30 lb of grain to make 1 lb of edible, boneless beef. The other 5% already goes to biofuels and other industrial products, including our burgeoning biopolymer sector. The argument is made that the products grown for animals and industry do not detract from the human food sources since these products are not fit for human consumption. One night while coping with a bout of severe insomnia, I watched Congressional proceedings on C-Span where testimony to this effect was being given to Congress by representatives of

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