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Determination of the Refractive Index of Water‐dispersible Granules for Use in Laser Diffraction Experiments
Author(s) -
Saveyn Hans,
Mermuys Dries,
Thas Olivier,
van der Meeren Paul
Publication year - 2002
Publication title -
particle and particle systems characterization
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.877
H-Index - 56
eISSN - 1521-4117
pISSN - 0934-0866
DOI - 10.1002/ppsc.200290006
Subject(s) - refractive index , particle size , laser , diffraction , extrapolation , mie scattering , particle size distribution , materials science , optics , particle (ecology) , range (aeronautics) , analytical chemistry (journal) , light scattering , scattering , chemistry , optoelectronics , organic chemistry , mathematics , physics , composite material , statistics , oceanography , geology
Modern laser light scattering equipment can cover a very broad particle size range by using complex algorithms, such as the Mie theory. A disadvantage of this theory, however, is that it requires the knowledge of the refractive index of the particles, which is not straightforward for powdered organic substances. In this study, thiram, a common dithiocarbamate fungicide, was used as a model compound. In a first part, a method was elaborated to determine the refractive index, based on refractive index measurements of solutions of the compound of interest in a range of solvents. Two different extrapolation techniques were compared. Both techniques were validated by applying them to the determination of the refractive indices of poly(vinyl acetate) and poly(methyl methacrylate). Secondly, the influence of the refractive index value on the generated particle size distribution in the laser diffraction software was investigated. It was observed that widely different particle size distributions can be generated by the laser diffraction software for a single experimental data‐set. Therefore, accurate refractive index information is required to obtain reliable particle size distribution results.