Heterogeneous Nucleation in PA66: Efficency of Flow-induced Precursors vs Equivalent Loading of Carbon Nanotubes*

The nucleating efficiency of a known volume of flow-induced precursors in polyamide 66 (PA66) was established and compared to the nucleating efficiency of a volumetric and surface-area equivalent loading of carbon nanotubes loaded into quiescent PA66.  Fast Scanning Calorimetry (FSC) was used to establish critical cooling rates and rotational rheology was used to investigate flow-induced crystallization (FIC). The onset of crystallization time was found to be a function of CNT content, where higher CNT loading reduced the onset time.  Above the percolation threshold, CNT nucleation was maximized as quantified by the halftime of crystallization, overshadowing the heterogeneous nucleation that results from FIC.