GLASS-FIBERS IN SIMULATED LUNG FLUID - DISSOLUTION BEHAVIOR AND ANALYTICAL REQUIREMENTS

Dissolution rates of glass fibres were found to vary from 1 to 50 000 ng cm(-2) h(-1) under laboratory conditions approximating the environment in the extracellular fluid in the lung. Experimental conditions are shown to have an impact on dissolution. Test parameters were varied among the samples to minimize the effects of dissolution products in the fluid, and good agreement was obtained between different measures of dissolution rate. Seventy-nine compositions in the system SiO2-Al2O3-B2O3-P2O5-TiO2-CaO-MgO-BaO-ZnO-Na2O-F-2, were tested, including a slag wool composition. The effects of glass components on dissolution rate are consistent over a wide compositional range. The effect of glass structure was evident in the different dissolution behaviours of glass wools vs a slag wool. Build up of dissolved products in the fluid affected the mechanism of dissolution and the character of the residual material most strongly; the dissolution rate was significantly affected for rapidly dissolving fibres only.