Physical Chemistry
The relative partitioning of stable isotopes of carbon or oxygen during physical or biochemical processes results in distinctive isotope signatures in organic materials. This phenomenon of isotopic fractionation occurs because lighter isotopes react slightly faster than heavier isotopes in chemical pathways. In the paper and packaging industry, the ratio of carbon thirteen to carbon twelve helps identify the biological sources of polymers and additives used in surface coatings.
This isotopic distribution acts as a natural barcode that cannot be forged or altered by subsequent chemical treatment. It provides a baseline for tracking material origins.
Biogenic Discrimination
Plants utilize different photosynthetic pathways that cause varying degrees of isotope depletion. Through isotopic fractionation, plants using the C3 pathway, like trees and sugar beet, display different carbon isotope ratios compared to C4 plants like corn and sugar cane. This difference allows laboratory analysts to determine the botanical origin of bio-derived plastics and paper starches.
These measurements ensure that raw material sourcing claims are truthful.
Analytical Application
Mass spectrometers analyze the vaporized samples to record the precise isotope ratios. Understanding isotopic fractionation prevents misinterpretation of carbon ratios in blended barrier films. This helps verify that the polymer layer is biogenic rather than fossil-based.
This scientific methodology underpins the claims of bio-based plastics.
