Characterizing CaCO₃particle dispersion in blown film

A novel method for the visualization and quantification of the state of dispersion of calcium carbonate particles in thin blown polymer films is described. Particle imaging was achieved by elemental mapping using energy dispersive spectroscopy. This generated outlines of particles and agglomerates located close to the film surface. ImageJ software facilitated the extraction of the corresponding Feret diameters. Finally, the Bootstrap technique was used to estimate confidence intervals for the kurtosis of the Feret particle size distribution. Kurtosis is a statistic that describes the shape of a distribution's tails in relation to its overall shape. It therefore provides a measure that characterizes the degree of particle agglomeration. The proposed procedure was applied to analyze high-density polyethylene films prepared using different calcium carbonate masterbatches in which formulation parameters were varied.