Accession Number : ADA297042

Title :   Mechanistic Study of the Evaporation of Liquids from Porous Microparticles.

Descriptive Note : Final rept. Jan 94-Jan 95,

Corporate Author : EDGEWOOD RESEARCH DEVELOPMENT AND ENGINEERING CENTER ABERDEEN PROVING GROUND MD

Personal Author(s) : Rubel, Glenn O.

PDF Url : ADA297042

Report Date : MAY 1995

Pagination or Media Count : 31

Abstract : The objective of this study is to investigate the evaporation of volatile liquids from individual microparticles composed of an aggregate of primary porous particles. The evaporation of octyl alcohol from microparticles containing porous silica was measured using single particle electrodynamic levitation. Liquid evaporation rates were determined from changes in the particle- levitation electric field intensities. A class of Syloid silicas was chosen for this study because of their well-defined pore volumes and specific surface areas which both affect the liquid evaporation rate. It is shown that the silica matrix retards octyl alcohol evaporation, and the degree of evaporation retardation increases with decreasing silica pore radius. A shrinking core evaporation model is used to interpret experimental results, and pore radii are determined for each of the silicas. This study also demonstrates that single particle levitation can be used to determine the liquid absorption capacity of solid particles. jg p.3

Descriptors :   *LIQUIDS, *EVAPORATION, *POROUS MATERIALS, CORES, MODELS, SILICON DIOXIDE, INTENSITY, ELECTRIC FIELDS, SOLIDS, SURFACES, PARTICLES, VOLATILITY, ABSORPTION, RETARDATION, ALCOHOLS, ELECTRODYNAMICS, OCTYL RADICALS.

Subject Categories : Inorganic Chemistry
      Organic Chemistry
      Physical Chemistry
      Laminates and Composite Materials
      Electricity and Magnetism

Distribution Statement : APPROVED FOR PUBLIC RELEASE