A new family of thermoplastic nanocomposites based on isotactic polypropylene (iPP) and inorganic fullerene-like tungsten disulfide (IF-WS 2 ) has been successfully prepared. A very efficient dispersion of IF-WS 2 material was obtained by mixing in the melted polymer without using modifiers or surfactants. The addition of IF-WS 2 nanoparticles induces a remarkable enhancement of the thermal stability of iPP, as well as an increase in the crystallization rate of the matrix when compared with pure iPP. The nucleating efficiency of IF-WS 2 solid lubricant nanoparticles on the a-phase of iPP reaches very high values (60-70%), the highest values observed hitherto for polypropylene nanocomposites. The incorporation of IF-WS 2 has also been observed to increase the size and stability of the crystals formed. The melting behavior of the nanocomposites indicates the formation of more perfect crystals as determined by differential scanning calorimetry and time-resolved synchrotron X-ray scattering experiments. The new nanocomposites show an increase in the storage modulus with respect to pure iPP measured by dynamic mechanical analysis. V V C 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45:

Isotactic polypropylene (iPP) blends were prepared with two different thermoplastic elastomers, a triblock copolymer styrene–ethylene butylene–styrene (SEBS) and a metallocenic ethylene‐octene copolymer (EO). The mechanical properties and morphology of blends with 0–50 wt% elastomer were studied to determine the influence of the presence of the elastomer on the improvement of toughness. The addition of a nucleating agent as a third component exerted a significant effect on the overall properties. Dynamic mechanical properties, flexural modulus, and impact strength as well as morphology were studied for nucleated and nonnucleated iPP/SEBS and iPP/EO blends. The improvement of impact properties found in binary blends was accompanied by a decrease in stiffness. However, the addition of the nucleating agent provided a good balance between impact strength and stiffness. From the results, SEBS was determined to be a better impact modifier for iPP than EO. The nucleated iPP/SEBS blends demonstrated improved mechanical properties compared with both the nucleated iPP/EO blends and the nonnucleated blends. POLYM. ENG. SCI., 48:80–87, 2008. © 2007 Society of Plastics Engineers

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