Structural and thermal behavior of 45S5 Bioglass®-based compositions containing alumina and strontium

The present research exposes the influence of 2 mol% of Al2O3 and 2 mol% SrO in 45S5 Bioglass(R)-based compositions. Four compositions were produced to elucidate the difference in how both oxides influence structure and thermal behavior separately and their synergy when together. Thermal properties, crystallization tendency, and sintering behavior was evaluated by differential scanning calorimetry, hot stage microscopy, and dilatometry. Changes of medium-range structures were characterized by Q(n) distribution of Raman spectroscopy and evaluation of P-31, Al-27, Na-23, and Si-29 environment obtained by magic angle spinning nuclear magnetic resonance. Despite Q(n) distribution was predominantly Q(2) in all samples, the composition criteria used enabled improved processing and stabilibity characteristics. The addition of Al2O3 and SrO promoted larger sinterability parameter (S-c) which indicates better sintering behavior, the glass stability against crystallization doubled (K-H) compared to 45S5 and the processing window enlarged from 106 to 171.