Two-step formation of entanglement from disentangled polymer melt detected by using nucleation rate

Shinichi Yamazaki, Fangming Gu, Kaori Watanabe, Kiyoka Okada, Akihiko Toda, Masamichi Hikosaka

Research output: Contribution to journalArticle

46 Citations (Scopus)

Abstract

"How do chain molecules spontaneously entangle from completely disentangled polymer melt?" remains the most interesting unsolved problem. In order to solve this problem, we used the concept that the melt of "nascent" polymer crystallized during polymerization just after melting does not include any entanglements. We succeeded in detecting the increase of entanglement density νe with the increase of annealing time Δt above the equilibrium melting temperature before isothermal crystallization. The increase of νe was detected by observing the decrease of nucleation rate I from the melt of nascent polymer with different Δts. I is a very sensitive detector of entanglements because the nucleation is a rearrangement process of chains to the crystalline lattice through the disentanglement. Therefore, I is significantly suppressed with the increase of νe. We found a two-step decrease of I with an increase of Δt for the first time. This should correspond to a two-step increase of νe with an increase of Δt. This indicates that simple entanglements such as twist or knot with lower order (one time knot) were formed within short time and then the complicated ones such as knot with higher order (two or three times knots) or loops (entanglements by loop conformation) were formed.

Original languageEnglish
Pages (from-to)6422-6428
Number of pages7
Journalpolymer
Volume47
Issue number18
DOIs
Publication statusPublished - Aug 23 2006

Keywords

  • Entanglement
  • Nascent polyethylene
  • Nucleation

ASJC Scopus subject areas

  • Organic Chemistry
  • Polymers and Plastics
  • Materials Chemistry

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