The Prepraration Of Tricalcium Silicate And Physico-Chemical Properties Of Calcium Silicate-Phosphate Bong Cement

Experimental purposes: (1) Tricalcium silicate (C₃S) was usually synthesized by high-temperature solid-phase reaction at 1500℃and above with repeated calcinations or long holding time. Study a process which can get high-purity powder C₃S at a lower temperature. (2) In order to adjust the setting time and degradability of (tetracalcium phosphate TTCP + dalcium hydrogen phosphate DCPA) system bone cement, optimize its compressive strength, improve its bioactivity, we try to compound C₃S that we have prepared to (TTCP + DCPA) system bone cement, and explore the physical and chemical properties of the composite bone cement.Experimental methods: (1) C₃S powders were synthesized by a novel co-precipitation method with doping CaF₂. The content of free CaO in the C₃S powders was analyzed using the glycol-ethanol method. The C₃S powders were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). (2) The stting time of composite bone cement was determined by the Gill Morocco (Gilmore) Determination of needle; the mechanical properties of bone cement was estimated by the compressive strength of composites; after soking in the simulated body fluids (SBF), the changes of dissolution extracts pH value and the weight of bone cement along soaking time, and combining the micro-morphology of the bone cement which was observated by SEM and XRD, described the dynamic change of bone cement in the human body.Experimental results: (1) Pure C₃S could be obtained at 1350℃for 4 h by adding CaF₂ from 0.6 to 1.5wt%, compared with previous preparation technology, the synthesis temperature of C₃S was lowered and the holding time was reduced. (2) With the percentage of C₃S increasing, the setting time of bone cement increased correspondingly. (3) The compressive strength of composite bone cement was enhanced first, and then reduced along the percentage of C₃S increasing. When the percentage of C₃S was 40%, the compressive strength of cement reach its maximum 21.6MPa, which was higher than the strength of traditional (TTCP + DCPA )bone cement. (4) The composite bone cement has good degradability, and the degradability increased along the percentage of C₃S increasing. When the percentage of C₃S was 40%, the degradability of cement reach its maximum10.26%. After immersion for 7 d, the compound bone cement maintained higher compressive strength, the maximum was 27.84 MPa, and the pH value of soaking liquid closed to neutral.Experimental conclusion: The bone cement mixing with C₃S prolonged the setting time of (TTCP + DCPA ) system bone cement, improved its degradability and enhanced the compressive strength a bit. This compound bone cement overcame shortcoming poor degradability of (TTCP + DCPA) cement, and has suitable setting time, higher compressive strength and excellent bioactivity and security, therefore, it might be taken as a potential bone cement repair alternative material.