Gamma Radiation Dose Variation of Hydroxyapatite/Ultra High Molecular Weight Polyethylene (UHMWPE) Nano Composite as Orthopedic Implant Material

A study was conducted on gamma-ray modified nanoHydroxyapatite (HAp)/Ultra High Molecular Weight Polyethylene (UHMWPE) composite as orthopedic implant material. This study aims to characterize the effect of gamma radiation on the physical, chemical, and mechanical properties of UHMWPE/HAp composites so that they can be used as orthopedic implant materials. The composite film was irradiated with gamma rays at a dose variation of 0 kGy, 15 kGy, and 30 kGy and a dose rate of 8 kGy/hour. Composites before and after radiation were tested for physical, chemical and mechanical properties. Physical properties test includes surface microstructure analysis; chemical properties test includes phase and functional group analysis; mechanical properties test, including hardness, tensile strength, and elongation at break. The results obtained are gamma radiation from IRKA changes the chemical properties of composites in terms of crosslinking and the number of radicals, as well as mechanical properties in terms of hardness, tensile strength, and elongation at break with different changes from the initial state before radiation. The best mechanical properties were obtained at 25% HAp composition in a dose of 30 kGy with a hardness (shore A) of 97.17; tensile strength of 18.15 MPa; and elongation at break of 17.85%, so that the UHWMPE/HAp composite has potential as an orthopedic implant material following the Ultimate Tensile Strength (UTS) of cancellous bone ranging from 10-20 MPa.