Particle size characterization: comparison of laser difraction (LD) and scanning electron microscopy (SEM)

HEGEL, CINTIA; JONES CARLOS; CABRERA, FERNANDA; BUCALA, VERONICA; YAÑEZ MARIA JULIA

Cartagena de Indias

Congreso; ? 12 th Inter-American Microscopy Congress (CIASEM 2013); 2013

Sociedad Colombiana de microscopia

ABSTRACTTwo of the most significant properties of particles are size and shape; they often have direct influence on the materialsbehavior. Since the particulate systems are constituted by 3D particles of different size, the characterization of this propertyhas to be given by a particle size distribution (PSD). Among the most popular techniques for PSDs measurement, the imageanalysis (IA) presents some disadvantages: sampling errors, the analysis of only hundred or a few thousand particles torepresent the whole population, the use a 2-D projected image of a 3-D particle and long analysis times. In contrast, thelaser diffraction technique allows fast particulate systems characterization, processes a high number of particles per assayand provides highly reproducible results. However, LD provides no details about the particle morphology. Both techniquescan be considered complementary, however several data interpretation problems appear when the results are compared. Todo so, it is necessary to understand the meaning of the size descriptors given by each technique and under which conditionsthe comparison of results from different size analyzers can be done. In this sense, this work explores first the number ofparticles required to obtain reproducible PSDs by SEM. Then, it presents a comprehensive characterization of PVC particlesby assessing a set of size and shape descriptors. The PSDs obtained by IA-SEM and LD were mathematically transformedto be compared. Finally, IA-SEM data was used to evaluate the convenience of using more than one size descriptor torepresent the particles volume.