The increasing diversity of commercial polypropylene products in recent years, related to the increase in the production volumes of PP, has led to a high number of studies dealing with structure-specific nucleating agents (NA's) [1]. Experiments on sorbitol-based NA's suggest that the nucleation function of this group of nucleating agents is a result of hydrogen bonding and self-assembly. So far, nucleation studies have been conducted in an indiscriminate manner with little reference to the exact effect of PP structure on nucleating behaviour of NA's. However, given the variety of commercial PP structures produced today, the question on the existence of synergy between polypropylene structure and nucleating efficiency of NA's remains open. The SIST (Stepwise Isothermal Segregation Technique) has been used in this study as a fast and efficient method to characterize a group of random PP's having different structures, giving the lamellar thickness distribution. In addition, temperature sweep measurements were performed to study the effect of flow on the interaction between NA and PP. In this way, small discrepancies between different materials can be pointed out to assess the nucleating efficiency of the nucleating agent.
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