Influence of nucleating agent on the crystallization kinetics and morphology of polypropylene

Abstract The influence of three nucleating agents from different generations on the crystallization behavior of propylene homopolymer was studied by differential scanning calorimetry (DSC) and atomic force microscopy (AFM). The amount of nucleating agent used varied between 1000 and 2200 ppm. The new generation nucleating agent, Hyperform® HPN-68L, accelerates the crystallization more efficiently than the other nucleating agents tested. It was also possible to verify the effects of agglomeration and negative interaction between calcium stearate and sodium benzoate. Furthermore, AFM images allowed to differentiate the crystals generated by Millad® 3988 through the observation of a fibrillar intertwining network structure, with characteristic spacing and length of crystals, justifying its excellent performance to improve polypropylene optical properties.