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Bonding of alkaline and alkaline earth cations in Na‐Ca‐Sr polyphosphate glasses
Author(s) -
Morguetto Gabriel Felipe,
Tsunaki Lucas Ely Bins,
Schneider José
Publication year - 2020
Publication title -
international journal of applied glass science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.383
H-Index - 34
eISSN - 2041-1294
pISSN - 2041-1286
DOI - 10.1111/ijag.13645
Subject(s) - polyphosphate , alkaline earth metal , dissolution , metaphosphate , phosphate , phosphate glass , materials science , analytical chemistry (journal) , alkali metal , inorganic chemistry , crystallography , chemistry , organic chemistry , chromatography
Dissolution of phosphates bioglasses, for bone regeneration or controlled ion release, is a key property to be tuned by adequate selection of chemical species. Mixed Na‐Sr and Na‐Ca polyphosphate glasses exhibit definite bonding preferences of the stronger cations to O from chain‐end phosphates (Q 1 ) instead of random bonding to the network (Q 1 and Q 2 ). This behavior is important for the control of dissolution, as hydration starts from the reaction of H with O in Q 1 . To analyze this bonding preference in glasses with two alkaline earths competing for O, mixed Na‐Ca‐Sr polyphosphates (0.57‐ x ) Na 2 O· x /2 SrO· x /2 CaO·0.43 P 2 O 5 (0 ≤ x ≤ 0.30 molar fraction) were considered. 31 P nuclear magnetic resonance was used to analyze the short‐range environments of Q n groups, detecting preferential bonding of Ca and Sr to Q 1 . To probe variations in the medium‐range organization of the network induced by Ca or Sr, glasses with compositions (0.57‐ x ) Na 2 O· x MO·0.43 P 2 O 5 (M = Ca,Sr; 0 ≤ x ≤0.30 molar fraction), were analyzed using 31 P‐double‐quantum techniques. An increase in mutual Q 2 self‐connectivity relative to the base Na‐polyphosphate network was detected as Ca or Sr were added, indicating conversion of linear phosphate chains into rings.