Fabrication of β-tricalcium phosphate/polyacrylic acid composite granules as a potential bone substitute

Composite granules of β-tricalcium phosphate (βTCP) derived from limestone were fabricated by mixing with polyacrylic acid (PAA) for potential bone substitute applications. Samples with varying ratios were evaluated using X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), porosity analysis, and diametral tensile strength (DTS) testing. XRD confirmed the crystalline nature of βTCP, with peak intensities increasing as βTCP content increased. FTIR showed C=O stretching of -COOH and symmetric COO^- vibrations, with ν_s(COO^-) bands appearing in composites, indicating interactions between PAA and βTCP through Ca²⁺-carboxylate coordination. SEM revealed a porous structure in the composite granules, with pore size increased with βTCP content. Porosity was higher in all composite granules compared to PAA granules, while DTS values improved with increasing βTCP, indicating enhanced mechanical strength. In conclusion, composite granules were successfully fabricated by mixing βTCP derived from limestone with PAA, exhibiting promising characteristics as synthetic bone substitutes.