Will 70% Biobased Content Biodegrade?

When a brand states that a plastic contains 70% biobased material, does the figure refer to the origin of its carbon, the mass of the entire product, or its ability to degrade in the natural environment? These three concepts are often blended into a single marketing claim, yet they are fundamentally different in polymer science. Using a biobased-material report supplied by Fong Fai Plastics as a case study, this article sets out an interpretation framework for R&D, procurement, ESG, and brand teams.

The key takeaway: three terms answer three different questions

The essential distinction is this: biobased content describes the origin of the material; carbon-14 is a measurement tool for identifying that origin; and biodegradability describes what happens at the end of a product's life. All three may apply to a material, or each may be independent of the others.

1 | Biobased Content: Is the Denominator Carbon or Total Mass?

ASTM D6866 generally reports biobased carbon content as the percentage of biomass-derived carbon in total organic carbon (TOC). With mineral fillers, metals, inorganic flame retardants, or other carbon-free constituents, this percentage need not equal the biobased mass fraction of the whole product.

Thus, “69.4% biobased carbon content” means about 69.4% of the organic carbon measured comes from recent biomass. To claim biobased mass content for the entire product, use the appropriate mass balance, elemental analysis, and standard methods, such as the ISO 16620-4 framework.

2 | Carbon-14: Modern vs. Fossil Carbon

Cosmic rays produce carbon-14 (¹⁴C) from atmospheric nitrogen. The isotope enters CO₂ and then plants through photosynthesis. Living organisms continuously exchange carbon, preserving a ¹⁴C signal near contemporary atmospheric levels. After death, exchange stops; ¹⁴C decays with a half-life of about 5,730 years. In petroleum, coal, and natural gas, formed millions of years ago, ¹⁴C is generally undetectable. Recent biomass retains a measurable signal.

Laboratories can measure a sample’s ¹⁴C signal by methods such as accelerator mass spectrometry (AMS), then compare it with a modern reference to estimate contemporary or biogenic carbon. ASTM D6866 measures biobased carbon content only; it does not assess environmental impact, functional performance, regulatory compliance, or biodegradability.

Four considerations when interpreting test results

• Use representative samples: multilayer structures, inks, adhesives, and batch variation can affect results.

• Allow for uncertainty: ASTM D6866 notes interlaboratory uncertainty of about ±3 percentage points. Do not overinterpret small differences.

• State the basis: biobased carbon content, organic-carbon basis, or total-mass basis.

• Carbon origin is not carbon footprint: assess emissions through LCA, including agriculture, energy, transport, processing, and end of life.

3 | Biodegradability: Conditions, Time, and Acceptance Criteria

Biodegradation of a polymer means that microbial activity converts it, under specified environmental conditions, into carbon dioxide (aerobic), methane (anaerobic), water, inorganic salts, and biomass. Fragmentation, disintegration, or visible disappearance merely indicates a reduction in size; it does not establish that the polymer has been mineralized.

A biodegradability claim must therefore identify the environment (industrial compost, home compost, soil, freshwater, or marine conditions), temperature, moisture, microbial conditions, test duration, and acceptance criteria. Compostability is a specific subset of biodegradability and generally also requires compliance with disintegration, heavy-metal limits, and compost-quality or ecotoxicity requirements.

Common false equivalences

• Biobased plastic ≠ biodegradable plastic: Bio-PE and Bio-PET have durability similar to their fossil-derived counterparts.

• Fossil-derived ≠ necessarily nondegradable: some PBAT formulations can satisfy specified industrial-composting requirements.

• PLA ≠ rapid degradation in every environment: it typically requires the temperature, moisture, and time window of industrial composting.

• Oxidative fragmentation or physical powdering ≠ complete biodegradation: carbon conversion must be demonstrated by standardized tests.

Case Study: How Should GTE-8075’s 69.4% and 70% Be Interpreted?

According to the Fong Fai Plastics presentation, Beta Laboratory measured the biobased carbon content of GTE-8075 at 69.4%, while a USDA Certified Biobased Product label showing 70% is also presented. The two values can reasonably be understood as reflecting differences in rounding or label presentation. Any formal public claim should nevertheless be checked against the product, formulation, labeling rules, and scope covered by the currently valid certificate.

An unfinished press-release template in the presentation contains placeholders for the date, an executive’s name, and statements. This article does not treat that draft as citable evidence; official certification records should be checked again before publication.

Material Performance and Environmental Claims Require Separate Verification

According to the technical data in the presentation, GTE-8075 is a translucent material supplied in pellet form. It is listed with Shore A hardness of 75, a melt flow index of 4.7 g/10 min (ASTM D1238; 2.16 kg; 190°C), density of approximately 0.90–0.93, and tensile, elongation, and tear properties. These data support preliminary processing and mechanical-property assessments; proof of biobased origin is a separate line of evidence.

The presentation also compares rebound behavior in conventional EVA foam and biobased TPE. For footwear, cushioning, and sporting goods, rebound, compression set, tear strength, density, shrinkage, and thermal aging directly affect finished-product performance. However, even high performance combined with high biobased carbon content does not justify a biodegradability or compostability claim.

Recommended multi-track validation for R&D

• Origin track: verify biobased carbon using ASTM D6866 or ISO 16620-2; assess biobased mass content and supply-chain traceability separately where necessary.

• Performance track: assess expansion ratio, density, rebound, compression set, thermal shrinkage, hydrolysis resistance, and aging for the intended end use.

• End-of-life track: select an applicable biodegradability or compostability standard only after identifying the target market and treatment scenario.

How Brands and Buyers Can Select the Right Test: A Decision Table

Compliance-Oriented Wording for Direct Use

More precise: “For the sample and report submitted for testing, GTE-8075 has a biobased carbon content of 69.4%. The presentation also displays a USDA Certified Biobased Product label stating 70%. Biobased content does not establish biodegradability.”

Avoid: “Made from 70% plants, so it will naturally decompose after disposal”; “Using biobased materials means zero carbon”; and “Carbon-14 tested, so it is compostable.” Such claims conflate feedstock origin, product mass, carbon footprint, and end-of-life behavior.

Conclusion: Turning “Green Materials” into Verifiable Engineering Claims

Professional communication about sustainable materials is not a collection of environmental adjectives. It requires clear answers: Where does the feedstock carbon originate? How was it measured? Under what conditions does the product reach its end of life? Biobased carbon can reduce dependence on fossil feedstocks, but biodegradability requires separate testing, and any actual carbon-emissions benefit must be assessed through LCA. When R&D, procurement, and brand teams rely on the same evidence framework, an accurate 70% figure is less likely to become a misleading environmental promise.

Reference Standards and Sources

1. ASTM International. ASTM D6866-24, Standard Test Methods for Determining the Biobased Content of Solid, Liquid, and Gaseous Samples Using Radiocarbon Analysis. https://store.astm.org/d6866-24.html

2. ISO. ISO 16620-2:2019, Plastics — Biobased content — Part 2: Determination of biobased carbon content. https://www.iso.org/standard/72474.html

3. USDA BioPreferred Program. Explanation of ASTM D6866 and the Certified Biobased Product Label. https://www.biopreferred.gov/BPResources/files/Article_071119.pdf

4. ISO. ISO 16620-4:2016, Plastics — Biobased content — Part 4: Determination of biobased mass content.

5. European Committee for Standardization. EN 13432; ASTM International. ASTM D6400; ISO. ISO 17088 (standards for compostable plastics; select based on market and product type).

6. Fong Fai Plastic Industrial Co., Ltd. Biobased Materials presentation: GTE-8075 biobased carbon content, USDA label, technical data, and rebound illustrations (source of this article’s case study).

Editorial Note

This article provides general information on materials technology and environmental claims. It does not replace third-party certificates, legal or regulatory advice, or compliance assessments for specific products. Certification status, labeling rules, and standards may change. Before a product is placed on the market or any public claim is made, verify the latest certificates, test reports, and regulations in the sales market.

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