Annealing-induced morphological changes in segmented elastomers

J. W.C. Van Bogart, D. A. Bluemke, S. L. Cooper

Research output: Contribution to journalArticlepeer-review

Abstract

Thermal analysis has been used to study annealing-induced ordering in segmented elastomers. Twelve segmented elastomers were studied each having approximately 50% by wt hard segment content. Seven general classes of materials were examined including polyether and polyester polyurethanes, polyether polyurethane-urea, and polyether-polyester. Materials were slow cooled (-10°C min-1) from the melt to an annealing temperature (-10°, 20°, 60°, 90° or 120°C) where they were annealed (16, 12, 8, 6 or 4 days, respectively). Annealing was followed by slow cooling (-10°C min-1) to -120°C after which a d.s.c. experiment was run. In general, annealing resulted in an endothermic peak at a temperature 20°-50°C above that of the temperature of annealing. This phenomenon was observed in both semicrystalline and amorphous materials. The closer the annealing endotherm was to a crystalline endotherm without exceeding it in temperature, the larger its size. Annealing endotherms resulted from hard or soft segment ordering. Only one annealing endotherm was observed for a given annealing history, even though in some materials hard and soft segments could exhibit annealing-induced morphological changes. Hard segment homopolymers were studied yielding results similar to the block polymers containing shorter sequences of the same material. This suggests that annealing-induced ordering is an intradomain phenomenon not associated with the interphase between domains, or necessarily dependent on the chain architecture of segmented elastomers.

Original languageEnglish (US)
Pages (from-to)1428-1438
Number of pages11
JournalPolymer
Volume22
Issue number10
DOIs
StatePublished - Oct 1981

ASJC Scopus subject areas

  • Organic Chemistry
  • Polymers and Plastics
  • Materials Chemistry

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