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Effect of mixing conditions and polymer particle size on the properties of polypropylene/graphite nanoplatelets micromoldings

Renze Jiang , Piyush Lashkari , Shengtai Zhou and Andrew N. Hrymak EMAIL logo


In this study, properties of polypropylene/graphite nanoplatelets (PP/GNP) composites and corresponding micromoldings were systematically studied in terms of filler loading concentrations and mixing methods. PP of different forms, i.e., PP pellets and powders, were adopted to fabricate PP/GNP composites. Additionally, a comparative study of precoating GNP and PP powders using solvent-based solution blending and ultrasonication-assisted mixing was performed. Results showed that PP/GNP composites prepared using powder form PP resulted in at least one order of magnitude higher electrical conductivity than using pellet form PP and further reduced the percolation threshold from 12.5 to 10 wt%, which was related to the state of filler distribution within corresponding moldings. Morphology observations revealed that microparts prepared with powder-PP/GNP composites exhibited less preferential alignment of GNP particles along the flow direction when compared with those molded using pellet-PP/GNP counterparts, which was helpful in improving the overall electrical conductivity for PP/GNP micromoldings.

Corresponding author: Andrew N. Hrymak, Department of Chemical and Biochemical Engineering, The University of Western Ontario, London, ON, N6A5B9, Canada, E-mail:

  1. Author contributions: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.

  2. Research funding: The authors acknowledge the support of the Natural Sciences and Engineering Research Council of Canada Discovery Grants program (ANH). SZ is thankful for the support from the National Natural Science Foundation of China (52103040) and China Postdoctoral Science Foundation (2020M673217). RJ gratefully acknowledges support from Ontario Graduate Scholarship and Queen Elizabeth II Graduate Scholarship in Science and Technology.

  3. Conflict of interest statement: The authors declare no conflicts of interest regarding this article.


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Received: 2022-01-06
Revised: 2022-04-29
Accepted: 2022-05-07
Published Online: 2022-07-12
Published in Print: 2022-09-27

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