Investigation of layered calcium phosphates and related materials for Biomaterial applications

Cave, Matthew R. (2010). Investigation of layered calcium phosphates and related materials for Biomaterial applications. University of Birmingham. Ph.D.

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Abstract

The purpose of this study was to identify and investigate novel layered materials with potential as biomaterials. This study has concentrated on layered calcium phosphate phases and their analogues due to their obvious biocompatibility and potential for resorption. Materials were prepared using a range of synthetic techniques including ceramic methods, acid flux and hydrothermal synthesis. Some of the layered phases prepared were then modified using intercalation and exfoliation. Characterisation was performed mainly using powder X ray diffraction with thermogravimetric and fourier transform infrared providing further means of analysis. When possible, single crystal X ray diffraction was also utilised. Investigations were performed on metal alkyl phosphates with strontium pentyl and phenyl phosphate phases being fully characterised by single crystal X ray diffraction. To our knowledge, this represented a rare family of inorganic/organic hybrid materials whose structures have been characterised in any detail. These structures show inorganic metal phosphate layers separated by organic layers containing alkyl chains displaying an unexpected cooperative ordering. The intercalation and exfoliation properties of monocalcium phosphate monohydrate [MCPM] were studied and a monoamine intercalated version of this MCPM was successfully prepared. These materials were investigated as a component of a calcium phosphate bone cement system, whereby, the inclusion of this amine intercalated MCPM species had a potentially useful retarding effect upon the setting of the cement. Layered calcium pyrophosphates were investigated due to their similar lamellar structure and slower dissolution rates compared with MCPM. Two previously known layered calcium pyrophosphate phases were successfully synthesised, namely calcium pyrophosphate tetrahydrate (Ca2P2O7•4H2O) and calcium disodium pyrophosphate tetrahydrate (CaNa2P2O7•4H2O) and their intercalation, ion exchange and exfoliation reactions were studied to determine whether it was possible to exploit their layered structures. Results of this study indicated that these phases were highly stable, allowing limited modification. When modification was suggested it resulted in as yet unidentified new phases.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

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