Predicting the Linear Low-Density Polyethylene Content of Custom Polypropylene Blends and Post-Consumer Materials Using Rheological Measurements

Dominik Kaineder, Christian Marschik, Ingrid Trofin, Sabine Hild

Research output: Contribution to journalArticlepeer-review

Abstract

Contributing to a sustainable economy requires the use of pure recycled materials. Analyzing polyolefin post-consumer materials and cross-contaminations in these materials is an essential part in ensuring consistent product quality. Therefore, the aim of this work was to quantify the linear low-density polyethylene (LLDPE) content in polypropylene (PP)-dominant strips. The materials investigated included virgin PP, custom PP-LLDPE blends and PP post-consumer recyclates. To this end, differential scanning calorimetry (DSC) and parallel-plate rheometry were used. For complementary measurements, Raman spectroscopy and atomic force microscopy (AFM) were employed, confirming the morphological occurrence of LLDPE enclosed in PP up to 30 wt%. The DSC measurements demonstrated that the evaluated specific melt and recrystallization enthalpies alone are insufficient to quantify the LLDPE content, especially at 1–10 wt%. The rheometric results showed a strong correlation between the cross-over point (COP) and zero-shear viscosity for pure PP grades, and there was a deviation from this correlation depending on the LLDPE content in the PP-LLDPE blends. An approach for determining low (1–15 wt%) and medium (up to 30 wt%) LLDPE quantities in PP via two mathematical models is proposed based on the rheometric measurements of custom blends and can be applied to assess the level of LLDPE contamination in PP post-consumer materials.
Original languageEnglish
Article number3169
Number of pages23
JournalPolymers
Volume16
Issue number22
Publication statusPublished - Nov 2024

Fields of science

  • 205016 Materials testing
  • 210002 Nanobiotechnology
  • 210006 Nanotechnology
  • 103023 Polymer physics
  • 104 Chemistry
  • 104004 Chemical biology
  • 104018 Polymer chemistry
  • 205012 Polymer processing
  • 206001 Biomedical engineering
  • 211905 Bionics
  • 104017 Physical chemistry
  • 104019 Polymer sciences

JKU Focus areas

  • Digital Transformation
  • Sustainable Development: Responsible Technologies and Management

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