IN-VITRO TESTING OF SOLUBILITY OF THERMAL INSULATION FIBERS

This recent work presents the results of dissolution of glass fibers in corrosion medium. The main objective of this research was to obtain the information about long-term dissolution of three types commercially produced glass fibers (E-fibers, fibers Promaglaf HTI 1200 and Promaglaf HTI 1250), which are commonly used as thermal insulation. The long-term dissolution of fibers was investigated at the temperature of 37 C by dynamic flow-through tests in simulated lung fluid (SLF). The flow rate of SLF was 120 mlday -1 . In solutions, the pH values and changes in weight loss of fibers were measured and changes in corrosion medium were evaluated by AAS. Also the values of the time dependence of the normalized leach amount of glass components (NLi) were computed and were compared with the data of NLi obtained from kinetic model of UCT Prague. The changes in appearance and composition of the fibers were evaluated with SEM-EDS techniques. This research confirmed that all fibers were dissolving in SLF, but each type differently. E-fibers dissolved nearly congruently, compared to fibers Promaglaf HTI 1200 and 1250 which were less soluble than E-fibers and dissolved incongruently. That was caused by production of precipitates -calcium phosphorous and silica layers.