Thermal characterisation of metal stearate lubricant mixtures for polymer compounding applications

Justin Phillips, Michelle Weldhagen, Thobile Mhlabeni, Lucky Radebe, Shatish Ramjee, James Wesley-Smith, Maria Atanasova, Walter W. Focke*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


Metal stearate blends are potential lubricants and filler dispersants in polymer compounding. Therefore, the thermal phase behaviour of binary blends of calcium stearate and magnesium stearate with zinc stearate was investigated. Cooling curve studies indicated lower melting temperatures in both systems. X-ray diffraction studies revealed that this was due to the formation of solid solutions of variable composition rather than to eutectic formation. Rheology measurements showed that true fluidification only happened well above the apparent melting points established from cooling curves. Calcium carbonate filled polyethylene containing metal stearate mixtures showed lower melt viscosities than were achievable using only calcium- or magnesium stearate as the lubricant. These results suggest that metal stearate blends, in combination with a judiciously selected wax component, may offer advantages in lowering compound melt viscosity and facilitating better particle dispersion.

Original languageEnglish
Article number178906
JournalThermochimica Acta
Publication statusPublished - May 2021
Externally publishedYes


  • Dispersant
  • Filler
  • Lubricant
  • Metal stearate
  • Thermal analysis


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