Properties of polypropylene/(natural rubber)/organomontmorillonite nanocomposites prepared by melt blending

The aim of this work was to study the effects of an organomontmorillonite or organoclay (OMMT) on the properties of a thermoplastic elastomer blend prepared by melt blending and based on polypropylene (PP) and natural rubber (NR). The results obtained showed a slight improvement of the blend mechanical (strength, modulus, and elongation), thermal, and solvent resistance properties when the amount of the organoclay was 3 phr. Results obtained by XRD analysis showed that at 3 phr of organoclay loading there was a shift toward low angles of the organoclay (001) plane diffraction peak and a disappearance of the PP β–phase peak. This shift signifies an intercalation of the polypropylene/(natural rubber) chains between organoclay platelets. An SEM study revealed that at the 3 phr organoclay concentration the blend became tougher, and the organoclay was located both at the PP/NR interface and inside the NR dispersed phase. A DSC study showed a decrease of the melting temperature of the PP phase at the 3 phr organoclay loading. A rheological study revealed that the addition of organoclay had not increased the melt viscosity of the PP/NR blend, and the stiffness was related to the maximum torque increase as a function of the organoclay loading. J. VINYL ADDIT. TECHNOL., 2011. © 2011 Society of Plastics Engineers