Search

Hardening composite materials based on calcium phosphates (hydroxyapatite, monocalcium phosphate monohydrate) and polymer binders (polyvinyl alcohol, polyvinylpyrrolidone) were obtained. It was found that the amount of brushite and tricalcium phosphate grows with increasing calcium acid phosphate content in the composition. The introduction of polymeric binders into the composition of hardening composite materials promotes growth of their mechanical strength and inhibition of structural-phase transformations of calcium phosphates at 800°C. Compositions based on 5% solutions of polymers and powders of hydroxyapatite or its mixtures with weight content 10 – 40% monocalcium phosphate monohydrate can be used as a consumable for 3D printing of calcium phosphate biomaterials and ceramic.

Ceramic in the system Ca2P2O7–Ca(PO3)2 was obtained by firing cement stone fabricated from a powder mixture which included β-tricalcium phosphate β-Ca3(PO4)2 and monocalcium phosphate monohydrate Ca(H2PO4)2 ∙ H2O. The molar ratio Ca/P of the initial powder mixtures was set as Ca/P ≤ 1. X-ray phase analysis shows all ceramic samples after firing at 1000°C to include β-calcium pyrophosphate β-Ca2P2O7, and a sample of the ceramic made from a powder mixture with the maximum content of monocalcium phosphate monohydrate Ca(H2PO4)2 ∙ H2O also contained β-calcium polyphosphate β-Ca(PO3)2. The obtained calcium phosphate ceramic with reduced firing temperature can be used to develop a resorbable matrix for tissue engineering structures.

The introduction of 10 – 50% (by weight) brushite powder, preheated at 50° and then fired at 1200°C, into a permeating suspension based on hydroxyapatite powder heat-treated at 800°C results in partial decomposition of hydroxyapatite to the α- and β-modifications of tricalcium phosphate. The presence of a tricalcium phosphate phase in calcium phosphate foam ceramic promotes an increase of the porosity from 40 to 60% and the resorption with significant static strength reduction from 3 – 7 to 0.3 MPa.

Powder mixtures prepared by mechanical activation from synthetic hydrated acidic calcium phosphates Ca(H2PO4)2 · H2O and CaHPO4 · 2H2O were used to obtain resorbable ceramic in the system Ca (PO3)2–Ca2P2O7. The phase composition of the ceramic after firing in the interval 700 – 1000°C was represented by biocompatible and bioresorbable phases: calcium polyphosphate Ca(PO3)2, tromelite Ca4P6O19, and calcium pyrophosphate Ca2P2O7. The obtained materials can be used to fabricate resorbable implants for regenerative treatment of defects of bone tissue.