A System for the Continuous Generation of Phosphorous Aerosols from Red Phosphorus-Butyl Rubber. Chemical Characterization and Toxicological Evaluation of Airborne Mixtures

A system for the continuous generation of phosphoric acid aerosols from burning Red Phosphorus-Butyl Rubber (RPBR) is described. The system is primarily intended for inahlation toxicology experiments using high aerosol concentrations (ca. 0.3 to 3 g/cu m), but is adaptable to other studies where a time independent concentration of the aerosol is desired in a flowing system. The RPBR formulation is softened by addition of a small amount of hexane and extruded at a controlled rate at high pressure through an orifice. A precision hydraulic extrusion system using a micrometer adjustable high pressure hydraulic pump has been developed to control the extrusion rate. The emerging filament is ignited and burned in a flowing air stram for delivery to chambers. In addition to the extrusion-combustion system for aerosol generation, devices for recovering the spent aerosol and for monitoring its concentration are described.