Mechanical properties of acrylic bone cement containing PMMA-SiO₂ hybrid sol-gel material

An organic-inorganic hybrid material, poly(methyl methacrylate) (PMMA)- SiO₂ (SiO₂ content of 72 wt%), was prepared by incorporating PMMA structure units covalently into an SiO₂ glass network via the sol-gel approach. The hybrid sol-gel material PMMA-SiO₂ was subsequently used as the solid powder component of bone cement and its mechanical properties were evaluated. The effects of the addition of tricalcium phosphate (TCP), hydroxyethyl methacrylate (HEMA), and ethylene glycol dimethacrylate (EGDMA) on the properties of the sol-gel hybrid bone cement were also investigated. The influence of these components on the temperature rise during polymerization was discussed. It was found that the new bone cement containing PMMA-SiO₂ hybrid sol-gel material had higher modulus than that of Simplex®-P bone cement. The addition of TCP in the new bone cement increased the Young's modulus and the polymerization time; the inverse was observed for the tensile, bending, and compressive strengths, and the polymerization temperature. The addition of HEMA and EGDMA in the new bone cement had the opposite effect of TCP. The comparison between the new sol-gel bone cement and the commercial Simplex P bone cement was discussed.