Please use this identifier to cite or link to this item:

TitleCrystalline structure of polyamide 12 as revealed by solid-state 13C NMR and synchrotron WAXS and SAXS
Author(s)Dencheva, Nadya Vasileva
Nunes, Teresa G.
Oliveira, M. J.
Denchev, Z.
Polyamide 12
Solid-state NMR
Synchrotron Xray scattering
Issue date2005
JournalJournal of Polymer Science Part B: Polymer Physics
Abstract(s)The crystalline structure of polyamide-12 (PA12) was studied by solidstate 13C nuclear magnetic resonance (NMR) as well as by synchrotron wide- and small-angle X-ray scattering (WAXS and SAXS). Isotropic and oriented PA12 showed different NMR spectra ascribed to c- and c0-crystalline modifications, respectively. On the basis of the position of the first diffraction peak, the isotropic c-form and the oriented c0-form were shown to be with hexagonal crystalline lattice at room temperature. When heated, the two PA12 polymorphs demonstrated different behaviors. Above 140 8C, the isotropic c-PA12 partially transformed into a-modification. No such transition was observed with the oriented c0-PA12 phase even after annealing at temperatures close to melting. A c0–c transition was observed here only after isotropization by melting point. Various structural parameters were extracted from the WAXS and SAXS patterns and analyzed as a function of temperature and orientation: the degree of crystallinity, the d-spacings, the Bragg’s long spacings, the average thicknesses of the crystalline (lc) and amorphous (la) phases, and the linear crystallinity xcl within the lamellar stacks.
AccessRestricted access (UMinho)
Appears in Collections:IPC - Artigos em revistas científicas internacionais com arbitragem

Files in This Item:
File Description SizeFormat 
9. Crystalline Structure of Polyamide 12 as Revealed by Solid-State 13C NMR and Synchrotron WAXS and SAXS.pdf
  Restricted access
515,5 kBAdobe PDFView/Open

Partilhe no FacebookPartilhe no TwitterPartilhe no DeliciousPartilhe no LinkedInPartilhe no DiggAdicionar ao Google BookmarksPartilhe no MySpacePartilhe no Orkut
Exporte no formato BibTex mendeley Exporte no formato Endnote Adicione ao seu ORCID