Measurement of Particle Size in the Submicron Range - Evaluation of Liquid Exclusion Chromatography (LEC)

Abstract

<p>Herein is reported a theoretical and experimental evaluation of liquid exclusion chromatography (LEC) for the measurement of particle size distribution (PSD) and diameter averages for colloidal spheres of various compositions.</p> <p>Correction factors for axial dispersion have been derived for a general detector whose signal is proportional to the number of particles time particle diameter to the power gamma (γ) where γ varies from zero to six. This general detector includes a turbidimeter (γ=6) and a refractometer (γ=3).</p> <p>Equipment and operational variables and their effect on resolution were investigated experimentally. These included packing and pore sizes, bed length and carrier liquid flowrate.</p> <p>The use of LEC for the off-line monitoring of the growth of latex particles was investigated for the surfactant-free emulsion polymerization of two monomer systems-styrene and vinyl acetate.</p> <p>LEC can be used to quantitatively measure the size distribution and diameter averages of both organic latices and inorganic particles in the submicron range in an off-line analytical mode. LEC is sufficiently rapid for the off-line monitoring of latex particle growth in emulsion polymerization. With some modification it could be used in an online mode as a sensor for reactor control.</p>