Freeze-Dried Porous Composites Based on Sodium Alginate and Powders of Calcium Salts Synthesized from Mixed-Anionic Solutions Prepared from (NH4)2CO3 and (NH4)2H2P2O7 Taken in Different Proportions
Year: 2026
Type: article
Abstract: Freeze-dried porous (0.05-0.06 g/cm3) composite materials were prepared from homogeneous molding compositions containing distilled water (95 wt. %), fine inorganic powders of calcium salts (2.5 wt. %) and sodium alginate (2.5 wt. %). Aqueous solution of calcium chloride (CaCl2) and aqueous mixed-anionic solution prepared by mixing solutions of (NH4)2CO3 and (NH4)2H2P2O7 taken in different proportions were used for syntheses of fine inorganic powders. Molar ratios (NH4)2Н2P2O7)/((NH4)2CO3+(NH4)2Н2P2O7) of salts used for mixed-anionic solutions preparation were established as 0 (reference powder), 0.02, 0.04, 0.08 and 0.16. Quantities of aqueous solutions of calcium chloride (CaCl2) was taken to provide molar ratio CaCl2/((NH4)2CO3+(NH4)2Н2P2O7) equal 1.00 (reference powder), 1.02, 1.04, 1.08 and 1.16. Phase composition of synthesized inorganic powders included calcium carbonate (CaCO3) (mostly vaterite) and quasi-amorphous phase of hydrated calcium pyrophosphate (Ca2P2O7 xH2O). All synthesized powders contained adsorbed and occluded salts presented in the mother liquor after synthesis completed before separation of precipitate. Mother liquors were aqueous solutions of ammonium chloride (NH4Cl) (all syntheses) and calcium chloride (CaCl2) (syntheses from mixed-anionic solutions). As components of inorganic powders used as fillers in composite materials ammonium chloride (NH4Cl) and calcium chloride (CaCl2) provoked a partial cross-linking of sodium alginate in the stages of preparation of molding compositions, composite sample molding, freezing and freeze drying. All freeze-dried porous composite materials demonstrated high water absorption capacity 4700-9300%. The most pronounced cross-linked effect was observed for alginate matrixes loaded with powders synthesized at molar ratio CaCl2/((NH4)2CO3+(NH4)2Н2P2O7) equal 1.04 and 1.08 demonstrating lowest water absorption and dry mass-loss after dipping in distilled water for 12 hours. Prepared freeze-dried porous composite materials with alginate matrix and calcium carbonate and/or hydrated calcium pyrophosphate powders as a filler can be recommended for subsequent testing as extracellular matrix for soft/hard tissue repair, as wound dressings or bone defects fillers.
Source: Journal of Composites Science
DOI: 10.3390/jcs10110565
Authors: Marat M. Akhmedov, Tatiana V. Safronova, Olga T. Gavlina, Farhunda F. Nematova, Tatiana B. Shatalova, Vadim B. Platonov, Albina M. Murashko, Nikita M. Nikandrov, Dmitry M. Tsymbarenko, Olga V. Boytsova, Tatiana V. Filippova, Ekaterina A. Karpuk, Grigoriy M. Timofeev, Yaroslav Y. Filippov, Nikita A. Sazhnev, Natalia R. Kildeeva
Language: English
Subfield: Civil and Structural Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,172
OpenAlex ID: W7213877065