[article]
Titre : |
Measuring in microns |
Type de document : |
texte imprimé |
Auteurs : |
Henry Warson, Auteur |
Année de publication : |
2002 |
Article en page(s) : |
p. 17-19 |
Langues : |
Anglais (eng) |
Catégories : |
Latex Mesure Mesure -- Instruments Taille des particules
|
Index. décimale : |
667.9 Revêtements et enduits |
Résumé : |
The author details just a few of the methods and instruments available that are able to measure the size of fine particles down to 0.003 micrometers in diameter.
The methods of measuring fine particle sizes have seen major developments in the past few decades. This applies to fine solids, but especially to latex particules. The oldest method for separating solid particles by size was the use of a sieve. Later, a range of sieves with different meshes was used.
Woven sieves are available for measuring sizes of particles from several millimeters to 20 micrometers, although some care is needed in the latter case to ensure that the sieve does not become distortes. Shape has a strong influence on particule size by sieving.
Originally, the only method of measuring the size of latex particles was by direct microscopic observation, which could give a maximum magnification of about 400. The phase microscope with oil immersion increases magnification to a maximum of about 600. The latex is diluted at least 10 times before a drop is placed on a slide and a cover glass is pressed over it. The assumption here is that particles in latex are essentially spherical, but this is noy always true.
Simple observations can show whether particles in any latex are unisized or have a variety of sizes and shapes. In dealing with solids, size and shape have more significances. The minimum size which can be observed directly is about 0.4 micrometers. |
Note de contenu : |
- Modern methods
- Electrode method
- Light scattering
- Photo correlation spectroscopy
- Fine solids measurement
- Turbimetry
- Disc centrifuge
- FIGURES : 1a. Flow schematics of Horiba system - 1b. Operation of Horiba system - 2. Accusizer 780 particle sizing system - 3. Brookhaven instrument, showing the effects of spinning
- Equation 1. The stokes equation, which relates the sedimentation of particles to size and viscosity |
Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=28092 |
in POLYMERS PAINT COLOUR JOURNAL - PPCJ > Vol. 192, N° 4451 (04/2002) . - p. 17-19
[article]
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