Please use this identifier to cite or link to this item: http://hdl.handle.net/1822/12532

TitleMicrofibrillar composites based on polyamide/polyethylene blends, 1. structure investigations in oriented and isotropic polyamide 6
Author(s)Dencheva, Nadya Vasileva
Nunes, Teresa G.
Oliveira, M. J.
Denchev, Z.
KeywordsSynchrotron X-ray scattering
Solid state NMR
Polyamide 6
Issue dateJan-2005
PublisherElsevier Sci Ltd
JournalPolymer
Abstract(s)The present paper discloses the structural changes caused by heating of polyamide 6 (PA6) samples with different thermal and mechanical histories in the 30–240 8C range. Wide and small-angle X-ray scattering (WAXS and SAXS) of synchrotron radiation, as well as solid-state nuclear magnetic resonance spectroscopy (NMR) measurements are performed. The NMR spectra show that in both isotropic and oriented samples there is a co-existence of a and g-PA6 crystalline forms. Deconvolution of the WAXS patterns is performed to follow the temperature dependence of the unit cell parameters of the a and g-forms and also of the equatorial (ECI) and total crystallinity indexes (CI), evaluating the contributions of the two crystalline phases. Estimates for the long spacing and for the average thicknesses of the crystalline (lc) and amorphous (la) phases within the lamellae are calculated as a function of the heat treatment employing analysis of the linear correlation function calculated from the SAXS patterns. The X-ray results allowed the conclusion that upon heat treatment up to 160–200 8C, intensive transitions between the PA6 crystalline forms take place, whereby the content of the initial major crystalline phase decreases and that of the initial minor one increases reaching almost 1:1. Close to 200 8C a general trend toward increasing the content of the a-form is registered. The influence of annealing and quenching after melting on the PA6 crystalline structure is also studied.
TypeArticle
URIhttp://hdl.handle.net/1822/12532
DOI10.1016/j.polymer.2004.11.105
ISSN0032-3861
Peer-Reviewedyes
AccessRestricted access (UMinho)
Appears in Collections:IPC - Artigos em revistas científicas internacionais com arbitragem

Files in This Item:
File Description SizeFormat 
10. Microfibrillar composites based on polyamide_polyethylene blends.pdf
  Restricted access
905,64 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