Plastics Technology

MAY 2012

Plastics Technology - Dedicated to improving Plastics Processing.

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Page 28 of 75

Big Alcohol. But this defense ignores the reality that there is a finite amount of land on which crops can be grown, and if the economic incentives dictate that crops will sell for higher prices when made into biofuels and biopolymers than when made into food, then land will be set aside to do just that. Market theory would respond to this by using more land to produce all of the needed products. And this brings us to the next issue, the impact that agriculture has had on our environ- ment. Only energy production has had a greater impact on our environment than agriculture. Agriculture is the largest single source of greenhouse gases, accounting for 35% of all the car- bon dioxide, methane, and nitrous oxide that we release. This is more than the worldwide emissions from transportation or electricity generation. In addition, agriculture has cleared or significantly transformed large percentages of prehistoric grass- lands, savannahs, and temperate and tropical forests. Finally, fresh water has been part of the collateral damage associated with agriculture. Irrigation has drawn so much volume away from natural waterways that many large rivers, such as the Colorado, have diminished flows or have dried up altogether, and many places have rapidly declining water tables, including regions in the U.S. And where water is not disappearing it is being con- taminated. Fertilizers, herbicides, and pesticides are ubiquitous. While fertilizers have been an important ingredient in improved agricultural yields, nearly half of the applied fertilizer runs off and ends up in coastal waters where it impacts fishing grounds, another key element in the cycle of food production. And fish do not require large allotments of grain to be converted into food. Kermit the Frog had it right: It's not easy being green. Before we rush to replace petroleum with "renewable resources," we need to pause, take a breath, and truly understand the impact of siphoning off key resources designed to feed people to make our polymers. Biopolymers are an inherently good idea. But if this is to be done in a sustainable way, to use the vernacular, we need to make them from the parts of the plant that we do not eat or from crops that can grow in places and under conditions that would not sustain food production and therefore do not compete for those resources. Then we can get down to answering the technological questions regarding where biopolymers fit when it comes to requirements for efficient processing and the properties they offer relative to the incumbents. ABOUT THE AUTHOR Michael Sepe is an independent materials and processing consultant based in Sedona, Ariz. with clients throughout North America, Europe, and Asia. He has more than 35 years of experience in the plastics industry and assists clients with material selection, designing for manufacturability, process optimization, troubleshooting, and failure BOBMZTJT $POUBDU t NJLF!UIFNBUFSJBMBOBMZTU DPN Manifold System Available The Koolest Water Proven Extrusion Systems Our continuous and discontinuous screen changers, melt pumps, pelletizers, and static mixers, are often supplied as systems comprising these and other components. We have over 30 years' application experience in the extrusion industry and our products are known for their world class technology. You can reduce energy and resin costs, and improve product quality. Call us to learn more. Maag Automatik, Charlotte, NC 704-716-9000 Oldcastle, Ontario Fountain Valley, California Schaumburg, Illinois Hong Kong 1-800-265-4885 YOUR SOURCE FOR QUALITY MOLD COMPONENTS FOR OVER 40 YEARS PLASTICS TECHNOLOGY MAY 2012 27 s US designed & manufactured s Modular corrosion protected aluminum construction s Flexible port option s Viton O-rings & tie-rods included s 90 degree option available s 3D CAD file configuration

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