Propriedades Térmicas de Compósitos de Polipropileno e Bentonita Organofílica

Abstract

A Brazilian polycationic bentonite clay was used for producing an organophilic clay with the quaternary ammonium salt, cetyltrimethylammonium chloride. The salt treated clay (BENT-org) and untreated clay (BENT) were characterized by infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Then, each clay was mixed with polypropylene (PP) by melt intercalation in a counter-rotating twin-screw extruder. The composites were characterized by XRD, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The results from FTIR and XRD showed the presence of specific groups of the ammonium salt and their intercalation in between the clay layers. XRD analyses of the composites with 3 and 5 wt. (%) of BENT-org revealed peaks displaced towards smaller angles, suggesting the intercalation of the chain polymer into the clay layers. DSC results indicated that the clay may have acted as a nucleating agent as seen from the increase in the T∞ (crystallization temperature in the cooling) of the composites. Consistent with the TG results, the incorporation of clay into PP improved the thermal stability of the polymer in the composites with 5 wt. (%) of BENT and 3 and 5 wt. (%) of BENT-org.