Molecular Weight Change during Poly(p-oxybenzoyl) Whisker Formation

Yasuo Kato, Yuhiko Yamashita, Kunio Kimura, Seiji Endo, Toshihiko Ohta

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

Molecular weight changes during poly (p-oxybenzoyl) whisker formation from p-acetoxybenzoic acid in liquid paraffin were studied. Our electron microscope observation suggestd that the needle crystals in the very early stage of polymerization consist of stacks of oligomer lamellae. Here, the degree of polymerization of precipitated oligomers was found to be about 8, from analysis of oligomers dissolved in liquid paraffin by HPLC method. Furthermore, transesterification in the interlamellar regions starts as soon as crystals precipitate. The average DP of whiskers obtained with 3 min after crystal precipitation increases from 8 to 48. These crystals show fibrillation by crushing of whiskers in liquid nitrogen or etching in KOH solution. This fact indicates that reorganization into extended chain crystals occurs accompanied by the increase of DP. On the other hand, DP of the eventual whiskers increased by 1860. That is, the average molecular length exceeds 1 Jim. The formation of such high molecular weight polymers in the solid state polymerization is caused by the closely packed structure of the end groups.

Original languageEnglish
Pages (from-to)583-589
Number of pages7
JournalKOBUNSHI RONBUNSHU
Volume47
Issue number7
DOIs
Publication statusPublished - Feb 1990
Externally publishedYes

Keywords

  • Morphology Control
  • Poly(p-oxy benzoyl)
  • Polymer Whisker
  • Topochemical Polymerization

ASJC Scopus subject areas

  • Chemical Engineering (miscellaneous)
  • Materials Science (miscellaneous)
  • Environmental Science(all)
  • Polymers and Plastics

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