ARAUJO, S. S.; http://lattes.cnpq.br/5879783367155053; ARAÚJO, Sueila Silva.
Résumé:
Polypropylene (PP) and clay nanocomposites were prepared by the melt
intercalation process. Bentonite clay, provided by Bentonit Uniao Nordeste, of
Campina Grande, Paraiba (Brazil), was subject to a chemical purification
treatment in order to remove organic matter impurities. Raw and purified clays
were then modified with the organic salt cetyl trimethyl ammonium bromide.
Clays samples were characterized by infrared spectroscopy and x-ray
diffraction. Results showed that the purification and organofilization treatments
were successful. As a comparative, tests were also performed with a
commercial organoclay (Closite 20A) provided by Southern Clay Products,
Gonzales, Texas (USA). PP/bentonite nanocomposites with 1, 3 and 5 %
organoclay loading (by weight) were prepared in a counter-rotating twin-screw
extruder coupled to a Haake rheometer. Test specimens were injection-molded
for mechanical and thermal characterization. The composites morphology was
evaluated by x-ray diffraction. Hardness, impact, and heat deflection tests were
also performed. Then results showed that the type and amount of clay greatly
affect the morphology and mechanical properties of the composite. In general,
better results were obtained with 1% organofilic clay. Nanocomposites prepared
with the bentonite purified and organofilized in this study showed properties
similar to those prepared with the commercial organoclay tested.