Abstract
Glasses in the system 24.5Na2O.24.5CaO.6P2O5.xSrO.(45-x)SiO2 have been studied in the composition region of x = 0–15 mol%. The as-prepared glasses are transparent and have an amorphous network structure. On the other hand, heat-treated glasses are transformed to opaque white glass-ceramic characterized by their highly crystalline network structure. Crystalline apatite (calcium phosphate, Ca3(PO4)2), wollastonite (calcium silicate, CaSiO3), and strontium calcium phosphate [Ca2Sr (PO4)2) are the main well-formed crystalline species that played the major role in material bioactivity. Increasing SrO leads to enhancing material crystallite and enhances the hardness of the host glass matrix. The change of XRD spectra,31P NMR chemical shift, and hardness number upon increasing SrO are considered due to modification of the apatite Ca(PO3)2 to involve Sr ions inducing Ca2Sr (PO4)2 apatite one. Such species play the role in enhancing material properties and hardness.
Highlights
Porous inorganic materials have unique properties that can help biomaterials be developed for controlled loading stresses and/or the release of biologically active substances [1, 2]
SrO gives the glasses good advantages toward improvements of their properties like extremely high resistant to thermal shock, high mechanical strength, good chemical stability, crystallinity and bioactivity [19]. It is evidenced from x-ray diffraction (XRD) and FTIR Figs. 1 & 2, of the as-prepared glasses that the well-formed structural species are constructed in its amorphous state [8,21]
Bioglasses and glass ceramics containing different SrO concentrations have been studied by different structural techniques
Summary
Porous inorganic materials have unique properties that can help biomaterials be developed for controlled loading stresses and/or the release of biologically active substances [1, 2]. Bioactive glasses can actively stimulate bone growth by releasing critical concentrations of ionic dissolution products, which cause rapid expression of genes that regulate osteogenesis and growth factor production[1, 5]. In this regard, strontium-based bioactive glasses have a strong ability to prevent osteoclasts from resorbing bone[6, 7]. SrO has recently been shown to improve the surface adhesion properties of strontium-containing glasses, resulting in increased material hardness. The lower electronegativity of Sr ions in the glassy network compared to Ca2+ ions is thought to be the reason for the increased surface adhesion[8, 9]. For Sr-doped glasses, the well-formed Ca-P species would be transformed more quickly into an apatite layer, allowing for more Ca2+ substitutions within the newly formed apatite layer[10]
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