Researchers at Rensselaer are building the first comprehensive framework to advance the discovery and design of cost-effective biodegradable plastics. The aim of the research, funded by a $405,821 grant from the National Science Foundation (NSF), is to provide a foundation for developing the next generation of “green” plastics.

The basis of the research is to develop reliable, sturdy plastics that, once disposed of, will biodegrade before reaching the landfill, according to Yvonne Akpalu, assistant professor of chemistry and chemical biology, and principal investigator of the project. She is collaborating with co-principal investigator Lealon Martin, assistant professor of chemical and biological engineering.

“As conventional petroleum-based, nonbiodegradable plastics continue to fill landfills and oil becomes increasingly limited and more expensive, the industry is looking for better ways to create plastic using alternative materials from renewable sources,” Akpalu said. “The goal of our research is to pave the way to develop affordable, durable, and environmentally friendly plastics that will affect nearly every aspect of society, from consumer packaging, to computer technology and applications in medicine.”

The researchers will incorporate small-angle light scattering techniques (similar to X-ray technology) in combination with X-ray diffraction simulations, multiscale modeling and a suite of complementary measurement techniques to build a robust understanding of the structure-property relationship of newly developed commercially available biopolymers and their nanocomposites.

“Think of deciphering the genetic code. We are going to do the equivalent to that in researching every angle and detail of these biopolymers and various nanomaterials — from the nanoscale to the microscale — to come up with a framework on how these materials interact and function,” Akpalu said.

The researchers note that plastic from biodegradable composites made from plant-based fibers already are on the market, but are expensive and not readily available. In recent years, industry has begun to introduce a more promising class of renewable plastics derived from a combination of nanoparticles and polyhydroxyalkanoates (PHAs), a family of polyesters naturally produced in bacteria.

“PHAs are fully biodegradable and have a wide array of physical properties that can range from stiff-brittle plastics and pliable rubber, to resins for coatings,” Akpalu explained. “Biopolymers, such as PHAs, from renewable sources will become critically important in coming decades, and learning how to control and modify their mechanical, thermal, barrier, and other properties by incorporating nanofillers is crucial.”

Adding various nanofillers can significantly improve the specialized properties of the polyesters, making them stronger or more pliable, for example. Still, little is known about PHAs and their interactions with various nanoparticles and the technology remains costly, the researchers said.

“One major aspect of our research is to find energy-efficient ways to produce plastics and part of that rests on understanding the science and engineering behind their manufacture,” Martin said. “The NSF grant and our subsequent work will allow us to guide and improve material processing applications.”

Published June 19, 2006