Formation mechanism of shish in the oriented melt (I) - Bundle nucleus becomes to shish

Shinichi Yamazaki, Kaori Watanabe, Kiyoka Okada, Koji Yamada, Katsuharu Tagashira, Akihiko Toda, Masamichi Hikosaka

Research output: Contribution to journalArticlepeer-review

43 Citations (Scopus)


We have solved the molecular mechanism of the formation of shish of isotactic-polypropylene (iPP) and polyethylene (PE) from the sheared melt based on kinetic study by means of polarizing optical microscope. We found that the rate determining process for the formation of shish is a nucleation process in the most range of degree of supercooling (ΔT) except for large ΔT of PE. We have shown a direct evidence of the formation of bundle nucleus from the oriented melt, which is consisted of elongated chains caused by artificial pins. For polymers, a universal mechanism of nucleation from the isotropic or oriented melt was proposed. We also found that there is a critical shear rate for the formation of shish. This experimental fact indicates that the shish will be formed when the elongation of chains will overcome the conformational relaxation of chains and chain conformation within the oriented melt is kept liquid crystal like one.

Original languageEnglish
Pages (from-to)1675-1684
Number of pages10
Issue number5
Publication statusPublished - Feb 14 2005


  • Nucleation
  • Shear flow
  • Shish

ASJC Scopus subject areas

  • Organic Chemistry
  • Polymers and Plastics
  • Materials Chemistry


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