The formation of exfoliated polymer–clay nanocomposites depends upon several factors such as the nature of the polymer, the nature of the clay, as well as the type, packing density, and size of the organic modifier on the silicate layers. The main aim of this work was focused on the role of the chemical structure of the organic modifier on the intercalation properties of the organo-modified clay into non-polar polymer matrices such as a polypropylene homopolymer. To achieve this purpose organo-montmorillonites containing different loadings of organic modifier with increasing molar volume were prepared and used to produce PP based nanocomposites. Morphology studies per- formed on the composites pointed out that two distinct aspects have to be considered for organic modification of the clays: the interlayer distance and the degree of the inorganic surface coverage, which are the main driving forces for the intercalation process. It was found that an intercalated structure was reached when either a large non-polar molecule, which ensures an optimal interlayer distance with a partial surface coverage or a mixture of small and large molecules leading to a slightly lower interlayer distance but to a higher surface coverage degree was used. Moreover, rheological, mechanical, and thermal studies indicated that the degree of dispersion and interaction between clay platelets and the polymer chains strongly depended on the interlayer spacing and clay surface coverage.

Intercalation degree in PP/Organoclay nanocomposites: role of surfactant structure

TERENZI, Andrea;
2008

Abstract

The formation of exfoliated polymer–clay nanocomposites depends upon several factors such as the nature of the polymer, the nature of the clay, as well as the type, packing density, and size of the organic modifier on the silicate layers. The main aim of this work was focused on the role of the chemical structure of the organic modifier on the intercalation properties of the organo-modified clay into non-polar polymer matrices such as a polypropylene homopolymer. To achieve this purpose organo-montmorillonites containing different loadings of organic modifier with increasing molar volume were prepared and used to produce PP based nanocomposites. Morphology studies per- formed on the composites pointed out that two distinct aspects have to be considered for organic modification of the clays: the interlayer distance and the degree of the inorganic surface coverage, which are the main driving forces for the intercalation process. It was found that an intercalated structure was reached when either a large non-polar molecule, which ensures an optimal interlayer distance with a partial surface coverage or a mixture of small and large molecules leading to a slightly lower interlayer distance but to a higher surface coverage degree was used. Moreover, rheological, mechanical, and thermal studies indicated that the degree of dispersion and interaction between clay platelets and the polymer chains strongly depended on the interlayer spacing and clay surface coverage.
2008
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11391/149386
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