Effects of TiO2 on fiber spinnability, structure, and mechanical properties of glasses derived from simulated lunar soils

The construction of lunar stations for research and habitation requires high-performance building materials that can adapt to the harsh lunar environment. One of the feasible building materials is fiber-reinforced composites, for which the composition of glass fibers can be designed like lunar soils, i.e., terrestrial basalt, and in turn the “lunar glass” can be drawn into fibers. Because of a wide variation of TiO2 in lunar soils, our study focused on a series investigation on the effect of TiO2 (0.55 wt%-6.14 wt%) on fiber spinnability and strength of the simulated “lunar glass and glass fibers”. The baseline glass composition was derived from a simulated TiO2-lean lunar soil and other glasses were made at different TiO2 doping levels. The addition of TiO2 was found to reduce the thermal stability of the melt, there appears a TiO2 threshold (6.14 wt%), at which fibers cannot be drawn without breakage because of melt devitrification. The fiber tensile strength exhibits a nonlinear characteristic with an apparent maximum at 1.52 wt% TiO2. FTIR and Raman spectroscopic studies were carried out to investigate the glass network structure responses to TiO2 modifications and show TiO2 functions as a network modifier, depolymerizing the silicate network. Statistical structure (FTIR & Raman based)–property modeling was attempted to further elucidate the effect of TiO2-induced structure change on Tg and fiber tensile strength. Good agreements were found between the model predictions and the measured values.