Compared Structure and Morphology of Nylon-12 and 10-Polyurethane Lamellar Crystals

C.E. Fernandez, M. Bermudez, A. Alla, S. Munoz-Guerra, E. Tocha, Gyula J. Vancso

Research output: Contribution to journalArticleAcademicpeer-review

10 Citations (Scopus)

Abstract

A comparative study of the structure and morphology of nylon-12 and 10-polyurethane (10-PUR) lamellar crystals, was carried out. Lamellar crystals were obtained by isothermal crystallization from diluted solution. Electron diffraction of lamellae combined with WAXS data recorded from crystal sediments indicated that nylon-12 crystallized in either α-form or γ-form according to the solvent chosen for crystallization. The α-form was the crystal modification predominant in doubly oriented films of nylon-12 prepared by epitaxial crystallization. On the contrary, 10-PUR invariably crystallized in α-form regardless crystallization conditions. The α-form of nylon-12 and 10-PUR shared the same crystal structure with hydrogen-bonded sheets made of antiparallel chains and stacked with progressive shifting along both b and c directions. Lamellar crystals of nylon-12 in γ-form and 10-PUR in α-form displayed similar morphological features but only the former appeared to be sensitive to temperature. Upon heating the nylon-12 crystals near to melting, the real-time WAXS analysis evidenced the occurrence of a partial γ-to-α crystal transition, and in situ AFM observations revealed the appearing of more or less regular ridges on the crystal surface. None of these changes were observed in 10-PUR crystals when subjected to similar treatment.
Original languageEnglish
Pages (from-to)1515-1522
Number of pages8
JournalPolymer
Volume52
Issue number7
DOIs
Publication statusPublished - 2011

Keywords

  • METIS-280528
  • IR-104504

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