Molecular Engineering of Liquid Crystalline Polymers by Living Polymerization. 6. Influence of Molecular Weight on the Phase Transitions of a 1/1 Copolymer of 2-(4-Cyano-4'-Biphenyl)oxy)ethyl Vinyl Ether and 8-((4-Cyano- 4'-Biphenyl)oxy)octyl Vinyl Ether

Abstract

A 1/1 molar ratio of 2-4-cyano-4'-biphenyl)oxyethyl vinyl ether (6-2) and 8-(4-cyano-4'biphenyl)oxyoctyl vinyl ether (6-8) was cationically copolymerized with the initiating system CF3SO3H/(CH3)2S in methylene chloride at 0C. All copolymers present narrow molecular weight distributions, and number average molecular weights which exhibit a linear dependence on Msub zero/Isub zero. Copolymers with degrees of polymerization lower than 14 exhibit an enantiotrpic nematic mesophase regardless of the thermal history of the sample. Copolymers with higher molecular weights exhibit an inverse monotropic smectic-A and an enantiotropic nematic mesophase in the first heating scan and only enantiotropic nematic mesophase in the subsequent heating scans. (TR)

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Document Details

Document Type
Technical Report
Publication Date
Oct 16, 1990
Accession Number
ADA229772

Entities

People

  • Myongsoo Lee
  • Virgil Percec

Organizations

  • Case Western Reserve University

Tags

DTIC Thesaurus Topics

  • Alkenes
  • Biphenyl
  • Chlorides
  • Copolymers
  • Glass Transition Temperature
  • Liquid Crystal Polymers
  • Liquid Crystals
  • Macromolecules
  • Methylenes
  • Military Research
  • Molecular Weight
  • Phase
  • Phase Transformations
  • Polymerization
  • Polymers
  • Transition Temperature

Fields of Study

  • Chemistry

Readers

  • Polymer Science and Technology

Technology Areas

  • Microelectronics