Carbon nanoparticles as effective nucleating agents for polypropylene

The effect of four nucleating agents on the crystallization of isotactic polypropylene (iPP) was studied by differential scanning calorimetry (DSC) under isothermal and non-isothermal conditions. The nucleating agents are: carbon nanofibers (CNF), carbon nanotubes (CNT), lithium benzoate and dimethyl-benzylidene sorbitol. Avramișs model is used to analyze the isothermal crystallization kinetics of iPP. Based on the increase in crystallization temperature ( T c ) and the decrease in half-life time (τ ½ ) for crystallization, the most efficient nucleating agents are the CNF and CNT, at concentrations as low as 0.001 mass%. Sorbitol and lithium benzoate show to be less efficient, while the sorbitol needs to be present at concentrations above 0.05 mass% to even act as nucleating agent.