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Free volume sizes in intercalated polyamide 6/clay nanocomposites

Winberg, Petra LU ; Eldrup, Morten LU ; Pedersen, N J; van Es, M A and Maurer, Frans LU (2005) In Polymer 46(19). p.8239-8249
Abstract
The effect of incorporating modified clay into a polyamide 6 (PA6) matrix, on the free volume cavity sizes and the thermal and viscoelastic properties of the resulting nanocomposite, was studied with positron annihilation lifetime spectroscopy, differential scanning calorimetry and dynamic mechanical analysis. At low concentrations of clay the fraction of PA6 crystals melting close to 212 degrees C was increased, while the fraction of the a-form PA6 crystals, melting close to 222 degrees C, was reduced. At higher concentrations of clay, a crystal phase with increased thermal stability emerged. Addition of more than 19 wt% clay caused a reduction of the heat of fusion of PA6. An unexpected reduction of the Delta C-p at the glass transition,... (More)
The effect of incorporating modified clay into a polyamide 6 (PA6) matrix, on the free volume cavity sizes and the thermal and viscoelastic properties of the resulting nanocomposite, was studied with positron annihilation lifetime spectroscopy, differential scanning calorimetry and dynamic mechanical analysis. At low concentrations of clay the fraction of PA6 crystals melting close to 212 degrees C was increased, while the fraction of the a-form PA6 crystals, melting close to 222 degrees C, was reduced. At higher concentrations of clay, a crystal phase with increased thermal stability emerged. Addition of more than 19 wt% clay caused a reduction of the heat of fusion of PA6. An unexpected reduction of the Delta C-p at the glass transition, contradicting the measured reduction of the heat of fusion, was detected, indicating an altered mobility in the non-crystalline regions. The viscoelastic response of PA6/clay nanocomposites, as compared to unfilled PA6, pointed towards a changed mobility in the non-crystalline regions. At high concentrations of clay (> 19 wt%) an increase of the free volume cavity diameter was observed, indicating a lower chain packing efficiency in the PA6/clay nanocomposites. The increased free volume sizes were present both above and below the glass transition temperature of PA6. (c) 2005 Elsevier Ltd. All rights reserved. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Polymer
volume
46
issue
19
pages
8239 - 8249
publisher
Elsevier
external identifiers
  • wos:000231573100049
  • scopus:24044520740
ISSN
0032-3861
DOI
10.1016/j.polymer.2005.06.063
language
English
LU publication?
yes
id
7a35ef38-1fe0-446e-9b1d-791b2b5ad84a (old id 152519)
date added to LUP
2007-07-13 16:50:52
date last changed
2017-08-27 05:13:05
@article{7a35ef38-1fe0-446e-9b1d-791b2b5ad84a,
  abstract     = {The effect of incorporating modified clay into a polyamide 6 (PA6) matrix, on the free volume cavity sizes and the thermal and viscoelastic properties of the resulting nanocomposite, was studied with positron annihilation lifetime spectroscopy, differential scanning calorimetry and dynamic mechanical analysis. At low concentrations of clay the fraction of PA6 crystals melting close to 212 degrees C was increased, while the fraction of the a-form PA6 crystals, melting close to 222 degrees C, was reduced. At higher concentrations of clay, a crystal phase with increased thermal stability emerged. Addition of more than 19 wt% clay caused a reduction of the heat of fusion of PA6. An unexpected reduction of the Delta C-p at the glass transition, contradicting the measured reduction of the heat of fusion, was detected, indicating an altered mobility in the non-crystalline regions. The viscoelastic response of PA6/clay nanocomposites, as compared to unfilled PA6, pointed towards a changed mobility in the non-crystalline regions. At high concentrations of clay (> 19 wt%) an increase of the free volume cavity diameter was observed, indicating a lower chain packing efficiency in the PA6/clay nanocomposites. The increased free volume sizes were present both above and below the glass transition temperature of PA6. (c) 2005 Elsevier Ltd. All rights reserved.},
  author       = {Winberg, Petra and Eldrup, Morten and Pedersen, N J and van Es, M A and Maurer, Frans},
  issn         = {0032-3861},
  language     = {eng},
  number       = {19},
  pages        = {8239--8249},
  publisher    = {Elsevier},
  series       = {Polymer},
  title        = {Free volume sizes in intercalated polyamide 6/clay nanocomposites},
  url          = {http://dx.doi.org/10.1016/j.polymer.2005.06.063},
  volume       = {46},
  year         = {2005},
}