Comparison of different -nucleators for isotactic polypropylene, characterisation by DSC and temperature-modulated DSC (TMDSC) measurements

A. Menyhárd, J. Varga, G. Molnár

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Abstract

The nucleating efficiency and selectivity of different β-nucleating agents was characterised and compared by differential scanning calorimetry, (DSC) and temperature-modulated DSC (TMDSC). The nucleating agents were the calcium salts of pimelic and suberic acid (Ca-pim and Ca-sub), linear trans-γ-quinacridone (LTQ), a commercial nucleator NJ Star (NJS) and an experimental product (CGX-220). The efficiency and the selectivity of Ca-sub and Ca-pim are extremely high. NJS is efficient above a critical concentration, which is connected with its partial dissolution in polypropylene melt. LTQ and CGX-220 possess strong overall nucleating ability and moderate selectivity. Using TMDSC, we found that three consecutive processes take place during the heating of β-nucleated samples cooled down to room temperature: reversible partial melting of the β-form, irreversible βα- recrystallisation, and the melting of the α-modification formed during βα-recrystallisation or being present in samples prepared with non-selective β-nucleators. Melting of the α-phase contains both reversible and irreversible components.

Original languageEnglish
Pages (from-to)625-630
Number of pages6
JournalJournal of Thermal Analysis and Calorimetry
Volume83
Issue number3
DOIs
Publication statusPublished - Mar 1 2006

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Keywords

  • Calorimetry
  • Crystallisation
  • Efficiency
  • Isotactic polypropylene
  • Melting
  • Recrystallisation
  • Selectivity
  • Temperature-modulated DSC
  • α-modification
  • β-modification
  • β-nucleators

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Physical and Theoretical Chemistry

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