Effect of Clay Surface Charge on the Emerging Properties of Polystyrene−Organoclay Nanocomposites
Author
Summary, in English
A series of polystyrene-clay nanocomposites, based on two natural clay
types (Na-Montmorillonite and Hectorite) and two synthetic clays (Laponite and Li- Fluorohectorite), were prepared via in situ intercalative polymerization after surface modification with an organic ammonium cation (CTAB). The structural characteristics of
the organically modified clays as well as the nanocomposites were investigated by means of wide-angle X-ray scattering (WAXS), and the thermal properties were studied with TGA.
In the organically modified clays, the silicate interlayer spacing increases, and the magnitude seems to be directly correlated with the amount of clay surface charge. In the nanocomposites, polymer intercalation is also observed, but partial exfoliation is present,
modifying significantly the morphology of the material. The degree of dispersion of the clay platelets, as well as the resulting properties of the nanocomposites, were found again to be systematically, and almost linearly, correlated with the intrinsic surface charge of the
clays, which varied between 44 and 120 meq/100 g. Increased dispersion was seen in the nanocomposites made from clays with
low surface charge, here Hectorite and Laponite, suggesting that these can be suitable alternatives to the more employed
Montmorillonite for enhancement of thermal properties. The thermal stability was found to be better for the nanocomposites
than for the pure polystyrene.
types (Na-Montmorillonite and Hectorite) and two synthetic clays (Laponite and Li- Fluorohectorite), were prepared via in situ intercalative polymerization after surface modification with an organic ammonium cation (CTAB). The structural characteristics of
the organically modified clays as well as the nanocomposites were investigated by means of wide-angle X-ray scattering (WAXS), and the thermal properties were studied with TGA.
In the organically modified clays, the silicate interlayer spacing increases, and the magnitude seems to be directly correlated with the amount of clay surface charge. In the nanocomposites, polymer intercalation is also observed, but partial exfoliation is present,
modifying significantly the morphology of the material. The degree of dispersion of the clay platelets, as well as the resulting properties of the nanocomposites, were found again to be systematically, and almost linearly, correlated with the intrinsic surface charge of the
clays, which varied between 44 and 120 meq/100 g. Increased dispersion was seen in the nanocomposites made from clays with
low surface charge, here Hectorite and Laponite, suggesting that these can be suitable alternatives to the more employed
Montmorillonite for enhancement of thermal properties. The thermal stability was found to be better for the nanocomposites
than for the pure polystyrene.
Department/s
Publishing year
2013
Language
English
Pages
19656-19663
Publication/Series
Journal of Physical Chemistry C
Volume
117
Issue
38
Document type
Journal article
Publisher
The American Chemical Society (ACS)
Topic
- Physical Sciences
- Natural Sciences
Keywords
- Polystyrene organoclays nanocomposites
- wide angle x-ray scattering
- clay
- CEC
Status
Published
ISBN/ISSN/Other
- ISSN: 1932-7447