Biodegradability & Compostability
Test Methods to Validate Claims: The need exists for skillful testing to validate claims of compostability. Unproven or false claims may be prosecuted by FTC and harm consumers.
In ASTM and EN tests, all CO2 that is evolved from compost is captured.
The Nature of Composting: Composting is best understood as a combination of short periods of thermophilic (high heat) conditions (>45°C or 115F for 3-days to 2 weeks) followed by much longer periods (2 – 6 months) of mesophilic (<45°C or < 115F) behavior. Mesophilic degradation is remarkably efficient. Ideally, test standards would incorporate both heating levels, yet it has proven too difficult to adjudicate mesophilic and thermophilics methods among laboratories. Some European protocols recognize lower temperature or “home type” compost conditions for testing.
Family of Standards: To date the nexus of ASTM, EN and ISO methods for compostability have helped regulate and grow a legitimate and thriving biodegradable plastic movement, with little conflict. Woods End Laboratories’ grasp of the proper use of these methods and awareness of alternative protocols to round-out claims, make the laboratory extremely successful in pursuing customers’ broad based interests in compostability & biodegradability assurance.
Emergence of Standards: After 1995, standardized protocols to distinguish compostability as distinct from bio-degradability emerged. The family of tests are known as ASTM D6400 (USA) and EN 13432 and ISO 14855 (Europe). These test protocols are essentially equivalent to each other.
Compostable vs. Biodegradable: Biodegradability is a significantly broader category than compostability since it encompasses ambient environments. The new protocols for compostability testing originated from industry and appear to be mainly based on thermoplastic material such as PLA which has an elevated melting point (Tg) of 55°C. Synthetic plastics with fixed melt points must be exposed to temperatures at or above this to reduce molecular weight and trigger hydrolysis before becoming compostable.
Industrial vs. Other Composting: A consequence of ASTM D-6400 is the arbitrary distinction of “industrial” (high heat) composting in contrast to “other” composting. Controlling the test process around a high-heat parameter will, however, give thermoplastic materials the best opportunity to reveal their potential degradability, while obscuring plastics that have unique ambient degradability potential.
New advancements in bioplastics include biodegradable polyesters such as Polyhydroxyalkanoates, PVA, and PVOH’s which may degrade well at lower temperatures. New forms of PLA are recognized that do not possess the limiting Tg factor. Woods End Laboratory possesses skilled awareness of this “work-in-progress” for achieving high-quality scientific validation of biodegradable products at temperatures other than accepted industrial norms.
Strength of Satisfied Clients: Woods End’s clients in biodegradability testing include: DuPont, DowAgroSciences, FritoLay, KraftFoods, Natureworks, Novamont, Pepsico, Nordenia, Roy. F. Weston, Toray, US Army Environmental Center, Weetabix – and many more.
Woods End is a successful applicant for BPI-NSF certification.
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