ASTM D6866 for Biobased Content Testing
- ASTM D6866 was developed originally for biobased content determination of products for the USDA BioPreferred Program
- ASTM D6866 biobased content computation only considers Total Organic Carbon Content, not product weight
- The standard does not measure product biodegradability
ASTM D6866 was developed in the United States as a standardized analytical method for determining the biobased content of solid, liquid, and gaseous samples using radiocarbon dating. Specifically, ASTM D6866 was developed at the request of the United States Department of Agriculture to satisfy legislation requiring federal agencies to give preference in procurement to manufacturers using the greatest amount of biomass in their products (per the Farm Security and Rural Investment Act of 2002).
It was quickly established that radiocarbon dating was the only viable and accurate technique to use for the determination of a product's biobased content. A working standard of radiocarbon dating for industrial use was completed in 2004 and is now cited in US Federal Law (7 CFR part 2902).
ASTM D6866 is a widely used method in the bioplastics industry. Braskem, a leading Brazilian petrochemical company, is one of the many bioplastics companies that use ASTM D6866 to certify the biobased content of their products.
ASTM D6866 was first published in 2004. There have been several versions released since then. The current active version of the standard is ASTM D6866-11 effective April 1, 2011.
ASTM D6866 Measures Renewable Carbon
ASTM D6866 distinguishes carbon resulting from contemporary biomass-based inputs from those derived from fossil-based inputs. Biomass contains a well-characterized amount of carbon 14 that is easily differentiated from other materials such as fossil fuels that do not contain any carbon 14. Since the amount of carbon 14 in biomass is known, a percentage of carbon from renewable sources can be calculated easily from the TOTAL organic carbon in the sample.
ASTM D6866 quantifies the biobased content relative to the material’s total organic content and does not consider the inorganic carbon and other non-carbon containing substances present. To illustrate, here are some hypothetical formulations and their ASTM D6866 results:
Product 1 – liquid with 50% starch-based material and 50% water
Biobased Content = 100% (product 1 has 50% organic content and 100% of that fraction is biobased)
Product 2 – liquid with 50% starch-based material, 25% petroleum-based, 25% water
Biobased Content = 66.7% (product 2 has 75% organic content but only 50% of that fraction is biobased)
Product 3 – solid that is 50% glass and 50% polyethylene from petroleum
Biobased Content = 0% (product 3 has 50% organic carbon but from fossil sources; glass is not carbon-containing)
Product 4 – solid that is 50% glass and 50% polyethylene from biomass
Biobased Content = 100% (product 4 has 50% organic carbon and 100% of it is renewable)
Product 5 – liquid with 50% soy-based material, 30% petroleum-based, 10% water, and 10% inorganic substances
Biobased Content = 62.5% (product 5 has 80% organic carbon but only 50% of it is renewable)
ASTM D6866 Does Not Measure Biodegradability
It must be noted that ASTM D6866 only quantifies the biobased content of a material but results do not have any implication on the material’s biodegradability.
The terms biobased and biodegradability may be related, but they are not synonymous nor are they interchangeable. If a material is biobased, it comes from plants or animals, but it does not necessarily follow that it is biodegradable. A material is biodegradable only if microbes in the environment can break it down and use it as a food source.
Some forms of cellulose are, in fact, non-biodegradable while some that are derived from petroleum do biodegrade contrary to popular opinion. Nowadays there are synthetic plastic resins that will biodegrade and compost just like paper. There are also bioplastic materials, such as Braskem's bio-polyethylene, that do not biodegrade.
Other Topics:
Biobased Content Terms and Definitions
