摘要: For at least 20 years, a few companies looking to enhance their green credentials have been making products out of bioplastics—polymers derived from plants, wood chips, food waste, and other renewable materials instead of oil or natural gas. In principle, bioplastics can be a welcome alternative to the fossil fuel-based plastics that represent a growing environmental scourge across much of the globe. And with advances occurring at a rapid pace, bioplastics may yet fulfill that promise. Corn is among the feedstocks used to make bioplastics, even though it’s not a particularly green crop owing to the amount of fertilizer and water it requires. Image credit: Shutterstock/TB studio. For now, however, there are serious questions about how sustainable and climate-friendly bioplastics actually are, especially once you account for all the fuel, water, and fertilizer required to produce them. Likewise, there’s plenty of confusion over bioplastics’ biodegradability—whether this assortment of materials will quickly break down and be consumed by microorganisms in the environment instead of piling on beaches and in landfills. By better understanding the various tradeoffs presented by different bioplastics, researchers, companies, and policymakers might be able to better determine which options, if any, are viable replacements for conventional plastics over the long run. “Bio-based” plastics made from organic material are hardly a new idea. Humans have been using latex-rich plant sap to make balls and other elastic items for thousands of years. In the 1850s, chemists developed the first commercial synthetic polymer by combining nitrocellulose derived from wood pulp with camphor extracted from laurel trees. Dubbed “celluloid,” the material quickly became a popular replacement for ivory knife handles, chess pieces, and the like and was used in applications such as ping pong balls and movie film well into the 20th century. Galalith, a milk-based plastic invented in the 1890s, is …