Preparation of High Percentage <i>α</i>-Calcium Sulfate Hemihydrate via a Hydrothermal Method
- 1 Applied Materials Science, Department of Engineering Sciences, Uppsala University, Uppsala, Sweden
- 2 Applied Materials Science, Department of Engineering Sciences, Uppsala University, Uppsala, Sweden
- 3 Applied Materials Science, Department of Engineering Sciences, Uppsala University, Uppsala, Sweden
- 4 BioArctic Neuroscience AB, Stockholm, Sweden
- 5 Applied Materials Science, Department of Engineering Sciences, Uppsala University, Uppsala, Sweden
Abstract
α -calcium sulfate hemihydrate ( α -HH) is known to be suitable for application as bone void filler. High percentage of α -HH is obviously needed for medical applications, especially for implantation. Three commercially available calcium sulfate dihydrates (DH, CaSO 4 ·2H 2 O) with different sizes and surface morphologies were used as starting materials to synthesize high percentage α -HH via a hydrothermal method. The median particle sizes of the three types of DH were 946.7 μm , 162.4 μm and 62.4 μm, respectively . They were named as DH-L, DH-M and DH-S in this paper. The particle size distribution, morphology and phase composition of the raw materials were evaluated before synthesis. SEM results revealed that DH-L consisted of irregular large particles, while DH-M and DH-S were composed of plate-like particles with some small ones. High percentage HH can be obtained with proper synthesis parameters by hydrothermal method, specifically, 105 ° C /90 min for DH-L (achieving 98.8% HH), 105 °C /30 min for DH-M (achieving 96.7% HH) and 100 °C /45 min for DH-S (achieving 98.4% HH). All the synthesized HH were hexagonal columns, demonstrating that they were α -phase HH. The particle size and morphology of starting material (DH) have significant influences on not only the rate of phase transition but also the morphology of the synthesized α -HH. Calcium sulfate dihydrate cements were prepared by the synthesized α -HH. The highest compressive strength of calcium sulfate dihydrate cement was 17.2 MPa. The results show that the preparation of high percentage α -HH is feasible via a hydrothermal method and the process can be further scaled up to industrial scale production.
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