No.8（2013）12.Development of a method for detecting bio-based polyethylene pellets

Yoshiyasu Nagakawa, Shunji Yunoki, Masaaki Saito

  The bio-based polyolefins are chemically identical to conventional fossil-based materials, and therefore some method to distinguish bio- and fossil-based materials must be urgently established until they are widespread. The only method for distinguishing bio- and fossil-based materials is radiocarbon (14C) analysis. Liquid scintillation counting (LSC) is a possible candidate for the screening method. We investigated LSC of bio-polyethylene (PE) and fossil-PE. The counting rate of bio-PE pellets in a toluene-based scintillation cocktail was significantly higher than that of fossil-PE. PE was not dissolved in the scintillation cocktail. Pre-soaking of PE in toluene enhanced the counting rate of bio-PE pellets. Bio-PE with higher crystallinity showed lower counting rate. These results suggest that toluene of the scintillation cocktail permeated into non-crystalline region induced scintillation of bio-PE pellets under solid state. LSC is a useful screening method for detecting bio-PE.

Keywords
Bio-polyethylene, Detection, Radiocarbon, Liquid scintillation counting, Non-crystalline region

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