Phase structure of impact-modified polypropylene blends

J. Karger-Kocsis, A. Kalló, V. N. Kuleznev

Research output: Contribution to journalArticle

146 Citations (Scopus)


A morphological study of polypropylene/ethylene-propylene-diene terpolymer (PP/EPDM) and polypropylene (PP)/polyolefin thermoplastic rubber blends was conducted. Dispersion of the impact modifier in the blend was investigated by transmission and scanning electron microscopy (TEM and SEM). It was established that number-average particle size ( D ̄n) of the EPDM impact modifier increased with its melt viscosity. The differences in melt viscosities of the blended components were characterized by the phase viscosity ratio (μ). The course of D ̄n vs. log μ function was qualitatively in agreement with the Rayleigh-Taylor-Tomotika theory. Accordingly, high degree of dispersion of the impact modifier can be achieved if melt viscosities of the blended components are very closely matched, i.e. if μ {reversed tilde equals} 1. It was concluded from SEM results that, below an impact modifier content of 20%, the modifier formed the dispersed phase in the continuous PP matrix. In blends containing 50% of impact modifier, the latter may also form continuous phase depending on its type and μ value beside the still continuous PP phase (co-continuous network structure).

Original languageEnglish
Pages (from-to)279-286
Number of pages8
Issue number2
Publication statusPublished - Feb 1984


  • Polymer blends
  • ethylene-propylene-diene terpolymers
  • high-impact blends
  • morphology
  • polyolefin, polypropylene
  • thermoplastic rubber

ASJC Scopus subject areas

  • Organic Chemistry
  • Polymers and Plastics
  • Materials Chemistry

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