Study On The Mechanisms Of Simulative Mineralization Of Borosilicate Glasses

Bioactive glasses are the new kind of bioactive medical materials, which can be applied to prepare for bone reparation and bone tissue engineering scaffolds. In order to improve the bioactive and degradability, H12 borosilicate glasses were prepared by melting-derived route in this paper. The microstructure and bio-mineralization characteristic of H12 bioactive glass were investigated in detail by weight loss, pH changes and Ca2+ concentration of K2HPO4 solution during the mineralization conversion reaction and using XRD,FTIR,SEM,EDS techniques as well as in vitro simulative mineralization method and also compared with 0B bioactive glasses. The influence of the H12 bioglass components to the bio-mineralization performance were investigated by comparing the mineralization performance of 0B,1B and H12 bioglasses to provide definite theoretics for preparing this new type bioglass as well as improving and adjusting its bio-mineralization characteristic. In order to reveal the simulative mineralization mechanism of the H12 bioglass, the influences of initial pH value of K2HPO4 solution, the reactive temperature, the reactive time and the concentrations of K2HPO4 solution to the process of mineralization and the mineralization productions were investigatedPorous spherical HCA crystal formed on the surface of H12 bioglass by simulative mineralizing in 0.25M K2HPO4 solution at 37℃for 10 days and the mineralization speed is faster than the 0B bioglass, which showed the H12 bioglass processes favorable bio-mineralization performance. The influence of the H12 bioglass components to the bio-mineralization performance indicated that the join of boron element is conducive to the nucleation and growth of the apatite crystals and the mineralization speed of H12 is enhanced. The sodium element reinforced the ion exchange and hydroxylation reaction which in favor of nucleation and grow up. Aluminum element strengthened the net structure but weaken the ion exchange and hydroxylation reaction, which go against nucleation and grow up. The influences of initial pH value of K2HPO4 solution, the reactive temperature, the reactive time and the concentrations of K2HPO4 solution all have significant impacts on the process of mineralization and the mineralization productions. Analysis results showed that the process of apatite crystal formed contain five steps. The boron/silicon sol-gel and a double electrode layer formed are important factors of the apatite crystal.