Preparation and characterization of polypropylene-based systems with enhanced thermal conductivity.

In this contribution, polypropylene based-composites, containing multiwalled carbon nanotubes are prepared by melt-blending and characterized in terms of thermal conduction and dispersion (TEM, SEM, rheological test, OP, THz) but flexural and electrical characterization techniques are also considered to gain more insights about the potentials of realized systems. In details, the influence on properties of products of both two commercial polypropylene resins, different in MFI and the addition of a compatibilizer, as maleic anydryde grafted polypropylene (Ma-g-PP), is verified. Different melt-compounding and molding conditions in terms of temperature, time, screw speed, pressure, filler drying are considered to optimize them for enhanced thermal conductivity. Three different commercial MWNTs with the same aspect ratio, one neat and two chemically modified with carboxyl (†"COOH) and amino (†"NH2) groups, respectively, are compared to prove effects of functionalization on final properties of respective nanocomposites. Finally, melt-compounded hybrid composites, involving not functionalized carbon nanotubes (MWNT) and an additional particle, with different shape and sizes, as boron nitride (BN), zinc oxide (ZnO), calcium carbonate (CaCO3) and talc, respectively, are also taken into account to give rise to specific thermal conductive paths.