Obtenção e caracterização de nanocompósitos de PS / argila esmectítica. / Obtention and characterization of PS/ smectite clay nanocomposites.

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

27/07/2010

RESUMO

In this work, the obtention of organoclays and nanocomposites of polystyrene (PS) using these modified clays was studied. In a first part Brazilian smectites clays were modified to be used in clay containing polymer nanocomposites. Several quaternary ammonium salts and experimental methods to modify the clays were used. In particular four parameters were evaluated: the type of ammonium salt, the particle clay size, the temperature and time used during the process of modification. The samples obtained were characterized by X-ray diffraction (XRD), Foster swelling test and differential thermal analysis (DTG). The results indicated that the most two important parameters in the process of modification are the time and the temperature used. In a second part nanocomposites of PS with organoclays (one obtained in the first part, and commercial clay, named cloisite 20A) were obtained by melt intercalation method using a twin screw extruder and an internal mixer. The clays were incorporated to the polymer as a fine dried powder and as a suspension of ethanol. Nanocomposites were molded by compression and injection. The injection conditions were modified to evaluate their influence on the morphology of the samples. The nanocomposites samples were characterized by XRD, transmission electronic microscopy (TEM), DTG and mechanical tests. Small amplitude oscillatory shear (SAOS) and time sweep tests were carried out. Nanocomposites of intercalated structure were obtained. The ones obtained using the internal mixer were shown to present a finer microstructure. The experimental results revealed that the residence time was showed the most important parameter in obtention of nanocomposites.

ASSUNTO(S)

argila organofílicas nanocomposites nanocompósitos organoclay poliestireno polystyrene reologia rheology

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