Break It Down, Build It Up
It was back in the 1980s," Richard Wool, Ph.D., recalls. "A lot of waste management sites were running out of space. Barges full of garbage were plowing up and down the East Coast with no place to dock. The idea of having biodegradable plastics would address a number of issues like getting rid of the trash and cleaning up marine waste, which was becoming a huge issue at the time."
Wool, a professor of chemical and biomolecular engineering at the University of Delaware in Newark, is remembering the events that impacted his years as an ASTM International member. Those were the bad old days for waste management, when 3,000 full-to-the-brim U.S. municipal landfills closed in a five-year period, barges like the Khian Sea and the Mobro 4000 would become famous when cities around the world refused to offload the trash on board and it looked as though modern culture might drown in its refuse.
But they were also the days when Wool, then a professor and researcher at the University of Illinois, and other members of ASTM Committee D20 on Plastics rose to the challenge of creating standards that would provide a scientific basis for determining the biodegradability of materials. It was also when Wool's passion for improving the safety and sustainability of end-use products and engineered materials began.
When Committee D20 started to develop standards for plastics biodegradability in the 1980s, "it was a field that was run more by marketing managers than by scientists," Wool says. Without methods that would allow the standardized determination of whether a plastic-based material would biodegrade, manufacturers were engineering products that sometimes sounded more landfill-friendly to consumers than they actually were.
To bring some order to the field and offer manufacturers ways to make good on claims of degradability, Committee D20 formed Subcommittee D20.96 on Environmentally Degradable Plastics and Biobased Products; Wool helped lead subcommittee efforts in the biodegradable plastics section. Out of that group were born signature practices and methods that helped determine degradation endpoints, the photodegradability of plastics, compostability, and the anaerobic and aerobic degradation of plastic materials in various environments like soil and sewage sludge. While perhaps not covering the most savory of test subjects, these standards helped open the door to the development of biodegradable plastic materials and products that would improve waste management for decades to come.
Wool recalls gatherings where the standards were hashed out by industry stakeholders as "hot-debate meetings." It wasn't easy getting to consensus, he says, "but kudos to ASTM for being there as the nucleating agent to get the new field of green materials off in the right direction. ... It was a very unifying scientific experience for the development of biodegradable plastics. Dr. Ramani Narayan [a founding member of the subcommittee] was, and still is, a highly energetic, spirited leader of the environmentally degradable plastics section of ASTM, who was the catalyst for progress and an inspiration to us all."
While the work of Subcommittee D20.96 was an incubator for vast improvements in the sustainability of plastic materials, it also served as a breeding ground for Wool's subsequent interest in going beyond making plastics biodegradable to engineering materials that are made from biological organisms in the first place. "I became critically aware of the issues surrounding waste management, recycling, climate change and the protection of our natural resources," Wool recalled in a recent interview after receiving a Presidential Green Chemistry Challenge Award from the U.S. Environmental Protection Agency. "I began to wonder if there was a better way."
A lot of other scientists had been wondering the same thing. After the degradability and recycling developments of the '80s and early '90s, which continue to improve waste management today, the materials science field began to turn its attention from breaking materials down to building green materials and products from the ground up using renewable, biobased materials. With issues such as diminishing resources, toxicity and climate change facing industry, concerns about waste management evolved into a consciousness about the very building blocks of so many end-use products we use today. The late 20th century concern with biodegradability "ran full-kilter into what's called a green chemistry and engineering approach to the design of new materials," Wool says. "And that is where you design materials that are feasible and economical without causing any injury to human health and the environment."
In the last 15 years of his career, Wool has become an award-winning leader in green chemistry and materials design. Through his Affordable Composites from Renewable Resources, or ACRES, program at UD, Wool and his students have developed replacements for polystyrene, poly(vinyl chloride), adhesives, foams and composite resins from such biobased feedstocks as vegetable oils, lignin, chicken feathers and flax. Composite resins made from biobased materials developed in Wool's lab are now being produced for a worldwide market by Dixie Chemical and, according to the University of Delaware, "his discoveries have led to the development of soy-based composites used in boats, tractor panels and wind turbine parts."
One of Wool's latest technological breakthroughs - the plant-based EcoLeather that requires no tanning process - is poised to impact the fashion industry. Working with colleagues in UD's fashion and apparel studies department, ACRES developed this new material using plant fibers from flax, cotton, palm, corn and soybean oil. Prada is collaborating with Wool to use the leather substitute in their products.
Wool says he and his students use ASTM International standards frequently in their lab work, and he starts their standards education in the classroom. "On Day 1, I produce the ASTM standard for determining what is a biobased material [ASTM D7026]." As for the lab, Wool uses the example of EcoLeather: "There are about 40 ASTM standards that we use to determine how our new EcoLeather materials compare with existing leather. Almost everything we do in the composites business, when we compare our results from one lab to another, we are constantly citing our ASTM testing methodology for factors, fitness testing, all of the mechanical, thermal properties - they're all done in accord with ASTM standards."