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Polymer Blend Spiking Method for Quantifying Polypropylene Variants in 100% Polypropylene Blends.
Meysam Hashemnejad1, Ami Doshi1
1Cincinnati Technology Center, LyondellBasell, 11530 Northlake Drive, Cincinnati, OH 45249, USA.
Accurately identifying polypropylene types in recycled materials is crucial for effective recycling. A new crystallization elution fractionation (CEF) method precisely quantifies Homo-PP and Random-PP in recycled polypropylene blends.
Area of Science:
- Polymer Science
- Materials Science
- Chemical Engineering
Background:
- Accurate characterization of post-consumer recycled (PCR) polypropylene is vital for optimizing mechanical recycling and blending with virgin polymers.
- Distinguishing between isotactic Homo-PP (Homo-PP), Random-PP, and non-crystalline PP components in 100% PP materials is challenging.
- Existing methods struggle to precisely quantify PP variants in complex recycled streams.
Purpose of the Study:
- To develop and validate a solution-based crystallization elution fractionation (CEF) technique for precise PP variant quantification.
- To enable accurate determination of Homo-PP, Random-PP, and non-crystalline PP content in recycled polypropylene.
- To support informed material selection and enhance the efficiency of polypropylene recycling operations.
Main Methods:
- A novel solution-based crystallization elution fractionation (CEF) technique was employed.
- Linear low-density polyethylene (LLDPE) was introduced to facilitate the separation of Homo-PP from Random-PP in 100% PP samples.
- Established calibration curves were utilized for quantitative analysis of PP variants.
Main Results:
- The CEF technique successfully separated and quantified Homo-PP and Random-PP in PP blend systems.
- Accurate quantification was achieved across a wide composition range, from approximately 5 wt.% to 95 wt.% Random-PP.
- The method effectively resolved Homo-PP, Random-PP, and non-crystalline PP fractions.
Conclusions:
- The proposed CEF method provides a robust solution for characterizing PP variants in recycled materials.
- This technique offers valuable insights into PP composition, aiding in recycling process optimization.
- Enhanced understanding of PCR PP composition promotes more sustainable and efficient polymer recycling.

