A melt-quenched of mixture of alumina and silica (46 wt% Al2O3 or Al2O3(SiO2)(2)) was found to react with an alkaline silicate solution (Na2O)(SiO2)(1.2)(H2O)(9.5)) at low-temperatures to form a synthetic aluminosilicate inorganic polymer. The as-quenched material consisted of a mixture of amorphous and crystalline phases with a range of aluminium coordination environments. Upon reaction with the alkaline silicate solution, solid-state aluminium and silicon magic-angle spinning nuclear magnetic resonance (SS Al-27 and Si-29 MAS NMR) indicated that a conversion to four-fold aluminium coordination environments occurred, consistent with the formation of a three-dimensional cross-linked inorganic polymer comprised of NaAlO4 and SiO4 tetrahedra. Mechanical testing showed the compressive strength of the inorganic polymer increased as the Na2O/Al2O3 molar ratio decreased. Solution studies indicated that 73% of the aluminosilicate starting material was reactive. Scanning electron microscopy (SEM) showed the inorganic polymers had a porous nanoscale grain structure. Open porosity was confirmed by relatively high specific surface area values. Energy dispersive spectroscopy (EDS) and elemental x-ray composition mapping showed that the high-strength specimens had a composite microstructure consisting of 40% unreacted Al2O3(SiO2)(2) and an inorganic polymer binder Na2O.Al2O3(SiO2)(3.4). The high compressive strengths have been rationalized by this in-situ particle reinforced composite structure, consisting of similar to10 mum agglomerates of unreacted starting material bonded within a sub-micron aluminosilicate/inorganic polymer matrix. (C) 2002 Kluwer Academic Publishers.
Hos, J. P., Mccormick, P., Byrne, L., & Byrne, L. T. (2002). Investigation of a synthetic aluminosilicate inorganic polymer. Journal of Materials Science, 37(11), 2311-16. https://doi.org/10.1023/A:1015329619089