Biodegradable plastics – a green solution?

It is hard to decide which way the argument over biodegradable plastics is going. Many people like the idea of plastics which break down, but the lifecycle impacts are not proven one way or another. Some people prefer the notion of using non-biodegradable plastics for fuel or as a CO2 sequestering mechanism. Here is a relevant report from the Environmental News Network.





ITHACA, N.Y. As plastic wastes continue to stack up in landfills throughout the country and the world, a Cornell University fiber scientist is edging closer to creating a greener alternative.





Researcher Anil Netravali’s solution to the plastics problem? Fully biodegradable composites made of soybean protein and other biodegradable plastics and plant-based fibers.





“These new fully biodegradable, environment-friendly green composites have good properties and could replace plastic parts in the interiors of cars and trains, in computers, and in packaging materials and other consumer products,” said Netravali, a professor of fiber science in the College of Human Ecology at Cornell. “They also provide excellent insulation against heat and noise for use in applications such as cars. Although the plant-based fibers may not be as strong as graphite and Kevlar®, for example, they are low in cost, biodegradable, and replenishable on a yearly basis,” he said.





Netravali recently presented his research on green composites made from ramie fibers (which have a feel similar to silk), which are obtained from the stem of an Asian perennial shrub and the resin made from a soy-based material. The researcher notes that instead of nondegradable plastics based on petroleum products, green composites (also known as reinforced plastics) use natural fibers that, for strength, are embedded in a matrix made of a plant-based or other resin. “They will be made from yearly renewable agricultural sources and would be environmentally friendly because they would naturally biodegrade once they were thrown on a compost pile,” said Netravali of plant-based green composites that he says could become inexpensive alternatives for many mass-produced items.





Netravali’s research group is working with a number of fibers, including those obtained from kenaf stems, pineapple and henequen leaves, and banana stems. The resin materials he is researching include commercial resins, such as polyvinyl alcohol and polylactones, and those derived from microorganisms.