³¹P NMR characterisation of phosphate fragments during dissolution of calcium sodium phosphate glasses

Abstract

In this study we show using 31P NMR that phosphate glasses dissolve by a combination of chain hydration and P–O–P hydrolysis.

Effects of water immersion and humid weathering on the near‐surface mechanical properties of phosphate laser glass

“…After immersion for a long time, aqueous corrosion breaks the cross‐link structure and induces further hydration of entire phosphate chains, which causes the dissociation of phosphate chains from the glass substrate . The uniform dissolution of glass network is considered the main corrosion factor in aqueous solution for many phosphate glasses . Taking sodium calcium phosphate glasses for example, by inductively coupled plasma emission spectroscopy (ICP), Bunker et al revealed that the ion concentration of Na, Ca, and P in aqueous solution increased linearly with increasing immersion duration, where the ratios of Na, Ca, and P ions in the solution were found to be same with those of the bulk glass.…”

“…However, the poor water‐resistance of the PL glasses limits their some more applications. Most researchers agree that the interaction between water molecules and glass surface involves several processes, that is, hydration, hydrolysis, and leaching . Hydration can be considered a penetration process of intact water molecules into the glass substrate.…”

New calcium‐free Na2O–Al2O3–P2O5 bioactive glasses with potential applications in bone tissue engineering

“…In the other samples, weight losses of 2.7 ± 0.9% for NAP7 and 0.7 ± 0.2% for NAP10 after 7 days of incubation were observed. As mentioned previously, P 2 O 5 content and glass structure strongly affect the solubility of phosphate glasses. We are hypothesizing that the much faster degradation of NAP3 glass can be caused by the lower alumina concentration and consequently different structure in comparison to NAP5‐10 glasses, but this idea requires further studies to confirm it.…”

The influence of phosphorus precursor on the structure and properties of SiO 2 –P 2 O 5 –CaO bioactive glass

“…For PA-BG, 31 P NMR spectrum showed a main peak at ~2ppm and a minor peak at ~ -7.5ppm, which were assigned to 0 and 1 units, respectively 33 . This suggests that the majority of phosphorus atoms were present as orthophosphate ( 0 units, PO4, 74%) with the remainder present as P-O-X (X = P or Si, Q 1 units).…”

“…For TEP-BG and BP-BG, three resonances at approximately 2, -8 and24ppm were present on the 31 P NMR spectra. These resonances can be assigned to 31 P in Q 0 , Q 1 and Q 2 structural units, respectively 33 . Compared to PA-BG, the TEP-BG and BP-BG samples had a lower fraction of 0 units, a higher fraction of 1 and 2 units (table 2).…”