Synthesis and Characterization of Hydroxyapatite from Biowaste for Poly (methyl methacrylate) Composites

The aim of this work is to determine the chemical composition of hydroxyapatite (HAp) and evaluate the stress at the onset of plastic deformation and how quickly heat spreads through poly (methyl methacrylate) (PMMA) Composites. Sixteen samples of heat-cured PMMA were filled with snail shell hydroxyapatite (SHAp) and periwinkle shell hydroxyapatite (PHAp). Isopropyl tri (dioctyl pyro phosphate) titanate was used as a coupling agent on the hydroxyapatite. The HAp was synthesized by hydrothermal synthesis, and the PMMA samples were produced by the casting method followed by compression and curing. Scanning Electron Microscope-Energy Dispersive X-ray (SEM-EDX) spectroscopy was used to characterize the HAp, and Universal Testing Machine and Modulated Differential Scanning Calorimeter were used for Yield Strength (YS) and Thermal Diffusivity (TD) analysis of the PMMA composites, respectively. Design-Expert software using the optimal mixture design of experiment (OMDOE) method was used to design and analyze the YS and TD of the PMMA composites, with p < 0.05 considered statistically significant. The ratio of calcium/phosphorus (Ca/P) was 1.70 for PHAp and 1.60 for SHAp. The YS is between 19.04 and 48.06 MPa, and the TD is between 9.07 X 10-7 and 2.39 X 10-7 m2/s. The highest mechanical and thermal properties were obtained when PHAp and SHAp were combined, showing a synergistic property of the HAp.