Synthesis, Characterization Of Magnesium Borate Nanowires And Composite Nanohydroxyapatite/Collagen Membrane

For general synthesis method of nanowires, such as thermal evaporation and chemical vapor deposition, it often needs highly pure inert gases and complex equipments. In this dissertation, we try to design a novel method to synthesize Mg₂B₂O₅ nanowires. The mixture powders of Mg(BO₂)₂ and graphite are pressed into tablets and sintered directly in the vacuum. Large quantities of single crystalline Mg₂B₂O₅ nanowires are synthesized with typical diameter about 120¹80nm and the length about 50⁸0μm. This synthetical method has the attributes of low cost, simple process and fast reaction and also the promising application to realize industrialization. We investigate the influences of temperature, sintered time and the proportion of reactants on the synthesis of one-dimensional nano-material Mg₂B₂O₅. The morphology and structure are charactered and analyzed by XRD, FESEM, TEM and SEAD. Furthermore, the tribological properties of the Mg₂B₂O₅ nanowires as the additive of lubricating oil are investigated under the different load using the high temperature terminal face friction and wear tester.By analyzing the influences of temperature, pressure, time of heat preservation on the morphology and structure of the Mg₂B₂O₅, we can find that the different morphology and simple phase of Mg₂B₂O₅ nanowires are synthesized with the heating temperature in the range of 1150℃¹250℃. The SEAD result indicates that the nanowires we fabricated are anorthic single crystal with integrated crystal structure and few disfigurements. The mechanism of in-situ growth can be used to explain the growth of nanowires. The large quantity of the Mg₂B₂O₅ nanowires might find applications in enhancement of metal alloys and ceramics.The second part is on the preparation of nHA powders by the liquid method with neutralization reaction of H3PO4 and Ca(OH)₂. It indicates that the best Ca/P molar ratio is 1.67, and the best pH value is bigger than 8. The impurity in the nHA is eliminated after the sintering process at 800℃. Compact and porous nanocomposite membrane of nHA/Col is prepared by an in-situ polymerization method. The best condition for the synthesis of composite membrane is attempted to achieve by altering the content of collagen and the value of pH. nHA/Col composite structure is formed via the intertwined assembly of collagen fibers surrounded by HA nanoparticles. There are interactions existed between nHA and Col molecular. The results show that the composite structure is porous and consists of nano- hydroxyapatite (10nm 50nm²0nm 80nm) and collagen fiber. The pore size of the porous membrane is 15⁴0μm, and the nHA particles disperse uniformly in the collagen matrix. The crystallite phases and size of the nHA particles is similar to that of the natural bone, which indicates that the composite membrane can be applied to the experiments of biocompatibility.