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May/June 2009
Feature

Bringing New Life to Plastics

Standards for Biodegradable and Biobased Plastics

In the past, that plastic water bottle you sipped from during workouts and the plastic container in which you sealed your kids’ peanut butter and jelly sandwich for lunch became members of the living dead once you discarded them, remaining intact for years and even decades after they were trucked from your trashcan to be buried in the nearest landfill.

As the world has grown more and more environmentally conscious, long-lived plastic refuse has become less and less palatable, and manufacturers have explored alternatives to petroleum-based plastics, governments have ratcheted up their disposal requirements and consumers have put their money where their ideals are.

Not only is the end-of-life of plastics an issue, but the beginning-of-life of plastics is garnering serious attention, too. Biobased plastics (plastics and products made from renewable biofeedstocks as opposed to petroleum and fossil feedstocks) are being offered in the marketplace as approaches to reducing the carbon footprint of plastics.

ASTM standards have kept pace, notably in Subcommittee D20.96 on Environmentally Degradable Plastics and Biobased Products, part of Committee D20 on Plastics.

End-of-Life Issue

“The end-of-life of plastics has always been an issue,” says D20.96 subcommittee chair Ramani Narayan, Ph.D., university distinguished professor,
Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Mich. “Standards make a major impact … and enable the market to develop products that can be substantiated by scientific data.”

Narayan is a founding member of the subcommittee, which was formed in 1990. “At that time, standards were sorely needed,” says the professor, whose doctoral dissertation at the University of Bombay was on biopolymers. “This is still an emerging technology area,” Narayan notes, adding that about 5 percent of the total plastics used today are biobased or biodegradable.

But the demand is there. Companies are investing more in biobased and biodegradable plastics, and national governments are requiring more from manufacturers in a bid to shrink their carbon footprint and enhance environmentally responsible end-of-life disposal options.

Subcommittee D20.96 has responded to that demand, and today the group is responsible for 25 standards. Those standards cover such topics as outdoor exposure testing of photodegradable plastics, heat aging of plastics, anaerobic biodegradation of plastic materials under high-solids anaerobic-digestion conditions and the aerobic biodegradation in soil of plastic materials or residual plastic materials after composting.

The subcommittee also has standards in development that address topics such as the biodegradation of plastic materials in the marine environment by open system aquarium incubations, and aerobic degradation and anaerobic biodegradation of plastic materials under accelerated bioreactor landfill conditions.

In High Demand

The three most significant standards developed by Subcommittee D20.96 are D6400 and D6868 for biodegradable plastics and D6866 for determining biobased content.

ASTM D6400, Specification for Compostable Plastics, one of the most in-demand standards from Committee D20, addresses plastics and products made from plastics that are designed to be composted in professionally managed municipal and industrial composting facilities. D6400 focuses in part on whether those materials will disintegrate and biodegrade swiftly and safely at a satisfactory rate.

ASTM D6868, Specification for Biodegradable Plastic Used as Coatings on Paper and Other Compostable Substrates, covers requirements for labeling materials and products that have a plastic film or coating attached to compostable components when the entire product is designed to be composted in municipal and industrial composting facilities.

ASTM D6866, Test Methods for Determining the Biobased Content of Solid, Liquid and Gaseous Samples Using Radiocarbon Analysis, is a standard test method for determining the biobased content of biobased plastics. The U.S. government’s BioPreferred program, which mandates the procurement of biobased products, references D6866 as the standard to use when reporting on the biobased content of biobased products, according to Narayan. Biobased plastics and products are those in which the carbon is from biological sources as opposed to petro/fossil feedstocks.

“ASTM D6400 and D6868 are the basis for certifying that products are ‘compostable’ in professionally managed facilities,” says Steven Mojo, executive director of the New York City-based Biodegradable Products Institute and a longtime member of D20.96. “All are intended to be composted along with food scraps to create a useful soil amendment — compost.” BPI has, since D6400 was first published in 1999, applied D20.96 standards to certify items such as plastic cups, cutlery and bags; plastic-coated paper items; and even food service items based on bagasse, or sugar cane.

Internationally Applied

Multinational corporations and smaller firms and organizations worldwide have applied these standards, including BASF, DuPont, NatureWorks LLC, Metabolix-ADM (Archer Daniels Midland), Mitsubishi Chemical Corp., PURAC (The Netherlands) and many more, according to Narayan and BPI. Others include:

  • Plantic Technologies Limited, Australia, a manufacturer of starch-based polymers for packaging and other applications, which used D6400 in the manufacture of biodegradable plastic packaging systems.
  • The state of California, which has referenced both D6400 and D6868 in its labeling regulations, mandating that any product claiming to be compostable meet those standards, according to Narayan and Mojo. Those standards also are recognized by major retailers such as Wal-Mart as the basis of compostable labeling claims, according to Mojo.
  • Braskem, a petrochemical company based in Brazil, which has used D6866 in its manufacture of biopolyethylene from a sugar cane feedstock instead of a petroleum feedstock.
  • New York City-based Loftex USA, which debuted a biodegradable clothes hanger molded of a cornstarch-based polymer and produced to D6400 specifications.
  • Portland, Oregon-based StalkMarket, which launched the first BPI-certified compostable Ingeo plant-based plastics hot cup and lid system, which meets BPI’s composting requirements and ASTM standards. The Ingeo plant-based plastics come from NatureWorks LLC, a joint venture between Cargill, headquartered outside of Minneapolis, Minn., and Teijin Limited of Japan.

The world’s largest consumer products company, Cincinnati, Ohio-based Procter & Gamble, has been invested in D20.96 since the early 1990s. Charles A. Pettigrew, principal scientist in P&G’s global microbiology organization, and a D20.96 member since 1992, says of his firm’s involvement in the subcommittee, “The company was investigating the development of compostable materials for diapers. Because we needed to utilize biodegradable plastics, we needed representation on the D20.96 subcommittee.”

Pettigrew says that lately D20.96 has been more of value to P&G for its biobased and sustainable materials. That includes P&G’s recently sold Nodax technology, biobased and biodegradable polyester materials that are an alternative polymeric system replacing such items as polyethylene and polypropylene.

From Cradle to Grave and Back Again

“Sustainability is a very complex concept. It basically involves looking at materials from cradle to grave to cradle,” says Pettigrew, who notes that D20.96 standards have helped his organization explore alternatives to petroleum-based polymeric systems. “What D20.96 and what ASTM provide are a way to define this new industry. They provide a level playing field for companies to evaluate and characterize and define these polymers. And they allow us to clearly understand the environmental benefits.”

Today, D20.96 comprises 115 members from Australia, Canada, China, Germany, Italy, Japan, Romania, the United Kingdom and the United States. The subcommittee, which meets twice a year in April and November, includes companies that have a green focus; academic institutions; laboratories; and government organizations, including the U.S. Army and Air Force and the state governments.

Meeting and Contact Information

For more information about the group and its activities, contact Ramani Narayan, Ph.D., Michigan State University, East Lansing, Mich. (phone: 517-719-7163), or Brynn Murphy, D20 staff manager (phone: 610-832-9640).

 

Patricia Quigley is an award-winning journalist and public relations practitioner who has written for local, regional, national and international publications. She resides in southern New Jersey, where she earned a B.A. in communication and an M.A. in writing from Rowan University.