Promising formulations with phosphate modification outperformed the neat CAC encapsulants in all experiments performed, considering both powder and plate aluminium.
This focuses upon assessment of the degree of conversion, identifying phosphate modifications which prolong the presence of metastable CAC hydrates for up to days and also formulations that prevent any conventional phases forming at all and hence avoid conversion.
The series of formulations with polyphosphate to cement Calcium phosphate cement thesis ratio of 0. This binding phase, optimal formulations, is shown to be stable in to a minimum of days with elevated compressive strength.
It was determined from the results of this study that altering the average phosphate ion chain length in solution prior to mixing can be used as a tool to tune the fresh state properties, including the heat of hydration and setting time.
The phase assemblage over the long term is examined by XRD and TGA up to a period of days, elucidating trends in hydration behaviour with phosphate modification.
Formulations of CAC modified by sodium polyphosphate, sodium monophosphate and mixtures of these, in varying proportions, are investigated.
Download 67Mb Preview Abstract The effect of phosphate modification on CAC hydration is poorly understood, and the investigation in this thesis focuses on the sodium phosphate modification of a commercially available calcium aluminate cement, examining the following: Immediately after mixing the fresh state properties are investigated using isothermal calorimetry, to assess the effect of average phosphate chain length on the heat of hydration and thermal behaviour of pastes during the initial curing period.
NMR spectroscopy is used to positively verify the binding phase to be a calcium aluminium phosphate hydrate phase. The kinetics of long term hydration and phase assemblage development maybe affected with the addition of sodium monophosphate, and radically altered away from conventional CAC hydration and instead the formation of an x-ray amorphous binding phase.
Promising formulations with no conventional CAC hydrate formations are studied up to a period of days to confirm the longer-term stability of the alternate hydrates being formed. The disordered binding phase of this system is further investigated using solid-state nuclear magnetic resonance NMR to probe the environments of the 31P and 27Al nuclei.
Characterisation of these samples after hydrothermal treatment showed the formation of hydroxyapatite, boehmite and a zeolite type phase.ON THE PROPERTIES OF CALCIUM PHOSPHATE BASED CEMENTS Shubhashree Sahoo CR ON THE PROPERTIES OF CALCIUM PHOSPHATE BASED CEMENTS A thesis submitted in partial fulfillment of the requirements for the degree of Bachelor of Technology To Ceramic Engineering Department Calcium phosphate cement (CPC) is a hydraulic cement.
Thus, alternative cements with similar mechanical strengths are being explored.
Calcium phosphate cements (CaP) have been a material of high interest due to their bioactive and thermal properties. Figure XRD of calcium aluminate cement Figure Particle size distribution of calcium aluminate cement 33 Figure XRD of p-tricalcium phosphate 34 Figure p-tricalcium phosphate particle size distribution 34 Figure Typical surface roughness graph 35 Figure Drawing of pull-out test fixture and specimen 39 Figure Calcium Phosphate Cements loaded with Pantoprazole as Novel Bone Substitutes Michel Victor Furtado Araújo, Master of Science, Faculty of Dentistry.
Among them, calcium phosphate cements (CPCs) have been attracting great attention due to their excellent biological behavior (e.g.
biocompatibility, bioactivity and osteoconductivity),. CPCs were first created in the s, by Brown and Chow .
Advances in Applied Ceramics The credit for the formulation of the first calcium phosphate cement applicable for use in the clinical setting is rightly given to Brown and Chow of the von Calciumphosphat-Pulvern zur Einstellung von Prozessparametern für die Herstellung von Knochenzement’, PhD thesis.Download