Characteristics of Polypropylene/Graphite Nanocomposites Obtained by In Situ Polymerization

摘要

The nanocomposites based on fine-grained graphite (FGG) and isotactic polypropylene (PP) were synthesized via polymerization in situ. Molecular weight distribution, stereoregularity, the thermal properties (melting point and enthalpy) of PP in PP/FGG nanocomposites were determined. The reactivity of PP/FGG nanocomposites in the reactions of thermooxidation and chemiluminescence is studied. Data of thermogravimetric analysis indicate high improvement of the thermal stability of PP after the addition of carbon nanofillers. It is demonstrated that, even at low (less than 1%) concentrations, graphite retards the oxidation of polypropylene and speeds up the termination of PP peroxy macroradicals. It has been concluded that the mechanism of the protective action of graphite in the oxidation of PP involves inhibition due to the interaction of graphite nanoparticles with peroxy PP macroradicals. The average size of the reactive graphite particles was estimated from kinetic data on the reaction of graphite with radicals.