We prepare polypropylene (PP) composites with both pristine halloysite nanotubes (p-HNT) and PP grafted halloysite nanotubes (PP-g-HNT) using two processing techniques, solid-state shear pulverization (SSSP) and melt mixing. We address the role of isolated polymer-filler interaction effects on polymer nanocomposite property enhancement at similar, high levels of filler dispersion. As demonstrated by microscopy and rheology, nanocomposites prepared by SSSP with different fillers have very similar, well-dispersed states, eliminating differences in dispersion as a factor in property enhancements. The well-dispersed PP/PP-g-HNT nanocomposites exhibit a broad range of properties that are superior to those of PP/p-HNT, including tensile strength, PP non-isothermal crystallization onset temperature, and isothermal PP crystallization half-time. However, the Youngâs modulus is the same regardless of filler modification. Only superior filler dispersion contributes to Youngâs modulus enhancement in nanocomposites.
