Excess entropy and thermal behavior of Cu- and Ti-doped bioactive glasses

Abstract

International audienceBioactive glasses belong to the ceramic family. They are good materials for implantation due to their excellent capacities to create an intimate bond with bones. Copper is known for its anti-inflammatory, antibacterial, and antifungal properties. Titanium is biocompatible and resistant to corrosion. These chemical elements can be introduced in bioactive glasses to provide a wide variety of uses and to enhance the physiological properties of implanted biomaterials. In this work, bioactive glasses doped with different contents of copper and titanium were synthesized by the melting method. The purpose is to study the effect of doping metal element on the thermal characteristics (T g, T c, and T f). The results revealed that the increase of the content of copper and titanium in the glass matrix decreases the melting temperature and induces an increase of the thermal stability. The excess entropies of pure and doped glasses were calculated. Obtained results highlighted the decrease of the excess entropy with the increase of metal elements contents

The Influence of Cu2+ and Mn2+ Ions on the Structure and Crystallization of Diopside–Calcium Pyrophosphate Bioglasses

“…However, further additions of those oxides inverted that trend, resulting in a gradual decrease in T c and T p . Similar results have been achieved by E. Wers and co‐workers …”

“…Adding MnO to CaP-10 resulted in greater differences in chemical shift, from À83.5 ppm (CaP-10) to À79.5 ppm (Mn-5), revealing the higher depolymerizing effect of Mn 2+ on the glass structure, as observed in the 29 Si MAS-NMR spectra shown in Fig. 3a.…”

“…Samples for FTIR analysis were prepared by mixing a 1/150 (by weight) portion of the sample with KBr, which was pressed to obtain pellets. 29 Si MAS-NMR spectra were recorded for glass powders prepared from frit glass on a ASX 400 spectrometer (Bruker, Billerica, MA) operating at 79.52 MHz (9.4 T), using a 7-mm probe at a spinning rate of 5 kHz. The pulse length was 2 ls with 60-s delay time, and kaolinite was used as chemical shift reference.…”

“…Further, the~487 cm À1 band is attributed to Si-O-Si bending modes, 31 while the weak shoulder at~763 cm À1 is due to Si-O-Si symmetric stretching with simultaneous Si cation motions. 32 Figure 3 shows the 29 Si and 31 P MAS-NMR spectra of the parent glass CaP-10 and compositions with the incorporation of 1 and 5 wt% of doping oxides. The parent glass featured a broad 29 Si spectra (Fig.…”

“…32 Figure 3 shows the 29 Si and 31 P MAS-NMR spectra of the parent glass CaP-10 and compositions with the incorporation of 1 and 5 wt% of doping oxides. The parent glass featured a broad 29 Si spectra (Fig. 3a) implying toward a wider distribution Q n (Si) species in the glass structure with the peak centered at about À83.5 ppm indicating the dominance of Q 2 (Si) structural units.…”