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Preparation of Borosilicate Bioactive Xerogel and Research on Simulation of Mineralization

Author: LiuLang
Tutor: LiYaDong
School: Suzhou University
Course: Materials Science
Keywords: boron silicon xerogels vitro simulative mineralization Calcium Phosphate SEM nano HA crystal
CLC: TB383.1
Type: Master's thesis
Year: 2009
Downloads: 36
Quote: 1
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Abstract


Preparation of the need for traditional high-temperature glass melting process, even if the use of sol-gel process is also subject to high temperature calcination to complete, so it is difficult in the field of drug delivery direct application. Preparation of xerogel at room temperature near the process can be completed, it is hoped that the field of drug delivery used directly, but the mineralization of the xerogels and the ability to assess the degradation of work and have not seen the report public.This article firstly studied the sol-gel CaO-B2O3-SiO2 system and CaO-B2O3-SiO2-P2O3-line xerogels with different initial pH values of aqueous solutions of 0.25M K2HPO4 mineralization capacity to explore the xerogel mineralization mechanism, and gives the CaO-B2O3-6SiO2-0.25P2O3 xerogel mineralization model of phase transition process. Studies have shown that the biological activity of boron silicon xerogel process of mineralization: DCPD→TCP→ACP / HA.Using XRD, TG-DSC, ICP, FTIR, SEM and EDS analysis microstructure of boron silicon technology xerogel, the main group and the law of thermal decomposition. Studies have shown that the system of borosilicate xerogel formation process, the boric acid involved in the hydrolysis of TEOS polycondensation to form a certain number of> BO-Si≡bond hybrid. At the same time show that under the experimental conditions can be no flocculation, crystallization, such as stratification and defective structure with amorphous silicon boron xerogel.Studies have shown that the initial pH value has a significant influence in the composition of mineralization products of boron silicon-based xerogel, initial pH = 5 and 7, the main formation is DCPD and small amounts of TCP.CaO-B2O3-SiO2 xerogels soaked in the initial pH = 9,0.25 M K2HPO4 aqueous solution studies have shown that mineralization capacity, B / Si ratio of xerogels have a greater impact in mineralization products phase, when B / Si Comparison little, B will promote the HA content increase in the nucleation and growth, so that particle size increased HA; when the B / Si relatively large, B will hinder the increase of the content of the transformation of DCPD to HA, culminating in coexistence of two phase, DCPD and HA.CaO-B2O3-SiO2-P2O3 xerogels soaked in the initial pH = 9,0.25 M K2HPO4 aqueous solution studies have shown that mineralization capacity, P content in favor of an increase in calcium phosphate nucleation and growth form. mineralization products of 2CaO-B2O3-6SiO2-0.125P2O3 and 2CaO-B2O3-6SiO2-0.25P2O3 xerogels are coexistence of two phase, DCPD and HA. 2CaO-B2O3-6SiO2-0. 5P2O3 and 2CaO-B2O3-6SiO2-P2O3 xerogel mineralization products are single-phase HA.the study of mineralization product micro morphology shows that, HA morphology is related with ingredients of xerogels. When the B / Si ratio = 1, mineralization product of CaO-B2O3-SiO2 and CaO-B2O3-SiO2-P2O3 xerogels （x> 0.25 ）xerogels soaked in the initial pH = 9,0.25 M K2HPO4 are worm-like nano-HA crystals and the formation of porous structure of accumulation.Studies have shown that osteoporosis structure of boron silical xerogel has a result of fast mineralization. In the initial pH = 9,0.25 M K2HPO4 aqueous solution 2CaO-B2O3-6SiO2-0.5P2O3 mineralization xerogel responsive, when the immersion time of 1min DCPD formed, and then gradually extended with the mineralization into TCP （3d） and the HA phase （7d）. Mineralization product of the component analysis results showed that, Mineralization product HA of CaO-B2O3-SiO2 system and CaO-B2O3-SiO2-P2O3 xerogels in the initial pH = 9,0.25 M K2HPO4 aqueous solution was the poor calcium hydroxyapatite , Ca / P ratio of 1.36 1.58.

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