Nanopartículas de Fe3O4 funcionalizadas e nanocompósitos de base epóxi
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2015-12-17Autor
Lima, Bruno Henrique Ramos de
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The use of metal oxide nanoparticles in nanocomposite has provided new
and interesting properties and is one of the most promising areas in composites.
Compatibility between these nanoparticles and polymer matrix is the most critical
fator on development of these materials. In this context, this thesis project has
focused on study of synthesis and functionalization of magnetite nanoparticles
(Fe3O4) aiming its incorporation into bisphenol A based diglycidyl ether based to
produce nanocomposites with very high compatibility between dispersed and
matrix phases. Synthesis and functionalization of nanoparticles were performed
in a single step by thermodecomposition of iron (III) acetylacetonate in poly (1,4-
butanediol) with molar weight 1000, which served both as a solvent for the
reaction as a source of molecules for surface functionalization of the
nanoparticles. Nanoparticles with an average size of 8,4 nm and with high volume
fraction of organic layer were obtained and the synthesis was highly reproducible.
The produced nanocomposite exhibited high homogeneity of nanoparticles
dispersion and the absence of large agglomerates. The interaction between the
nanoparticles and matrix occurred through the chemical reaction between the
functional groups of the organic layer and the DGEBA, as was expected, and
through intercalation of DGEBA molecules between the molecules from the
organic layer, thereby creating a new interphase with unique properties. Due to
the high volume fraction of this new phase, the density and modulus of elasticity
exhibited behavior that could not be explained by traditional methods. A new
approach was used to develop a model that considered this third phase and set
more consistently to the experimental data obtained, and showing the domain of
this new interphase on the nanocomposite`s properties.