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T11 · Sustainability / LCASustainable Plastics & Circular EconomyGATE 2027 Syllabus (XE5)Shop-Floor Standard
Biobased Carbon Content Percentage Formula (ASTM D6866)
Measures the percentage of renewable modern bio-based carbon relative to total organic carbon in polymers using Accelerator Mass Spectrometry (AMS) radiocarbon dating (ASTM D6866).
Mathematical Canonical Relation
Plain Formula: Biobased Carbon % = (14C_sample / 14C_modern) * 100
Live Engineering Parameter Solver
Input your production or test values below for instant, verified output.
Verified Engine
pMC_sample
Range: 0 – 110 pMC
pMC_ref
Range: 95 – 105 pMC
Calculated Engineering Result:
20% Biobased Carbon
Engineering Verification:Qualifies for USDA BioPreferred certification.
When & Where to Apply
Use when certifying bio-PE, bio-PET, PLA blends, and USDA BioPreferred label compliance.
Common Engineering Pitfalls
- Confusing biobased carbon percentage (fraction of carbon atoms) with total biobased product weight fraction (which includes oxygen/hydrogen)
- Assuming biodegradable polymers are automatically 100% biobased (e.g., PBAT is fossil-derived biodegradable)
Physical Assumptions & Validity Limits
- Petrochemical fossil carbon contains zero detectable 14C (half-life 5730 years; fossil feedstocks are >100 million years old)
- Modern atmospheric biological carbon has standard 14C activity reference
- Clean organic combustion to graphite target for AMS detection
Variable Symbols, SI Units & Dimensional Specifications
| Symbol | Variable Meaning | SI Unit | Typical Industrial Range |
|---|---|---|---|
| \text{Biobased}\% | Biobased carbon content | % of Total Organic Carbon | — |
| ^{14}\text{C}_{sample} | Measured 14C isotope activity in sample | pMC (percent Modern Carbon) | 31.5 |
| ^{14}\text{C}_{modern} | Standard modern reference radiocarbon activity | pMC | 100.0 |
Worked Industrial Numerical Example: Bio-PET Beverage Bottle Resin Biobased Carbon Verification
Problem Statement:
Bio-PET synthesized from bio-based ethylene glycol (30 wt% of PET molecule) and fossil PTA has 14C sample activity measured at 20.0 pMC against 100 pMC modern standard. Calculate biobased carbon content.
Step-by-Step Numerical Solution:
- Apply ASTM D6866 formula: Biobased Carbon % = (20.0 / 100.0) * 100
- Calculate: 20.0%
Final Answer: 20.0% Biobased Carbon
💡 Engineering Interpretation: The Bio-PET bottle contains 20% renewable biogenic carbon atoms (derived from sugarcane bio-MEG), meeting USDA BioPreferred certification minimum threshold for biobased polyester.
Authoritative Technical Reference & Source Provenance
Standard Test Methods for Determining the Biobased Content of Solid, Liquid, and Gaseous Samples Using Radiocarbon Analysis by ASTM Committee D20 (ASTM International, 2024), ASTM D6866-24, Page 1-12.
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