Development of biomedical porous titanium filled with medical polymer by in-situ polymerization of monomer solution infiltrated into pores

Porous metallic materials can have a low Young's modulus, which is approximately equal to that of human bone, by controlling the porosity. On the other hand, certain medical polymers exhibit biofunctionalities that are not intrinsically present in metallic materials. Therefore, a composite consisting of these materials is expected to possess both these advantages for biomedical applications. However, in the case of using porous metallic materials, the deterioration of mechanical properties should of concern because a stress concentration may be induced near the pores. In this study, for the fabrication of the abovementioned composite, a versatile process for filling a medical polymer into a porous metallic material has been developed using porous pure titanium (pTi) and polymethylmethacrylate (PMMA). Then, the tensile strength and Young's modulus of pTi filled with PMMA (pTi/PMMA) fabricated using this process are systematically investigated. The tensile strength of pTi can be improved by the PMMA filling. Particularly, the improvement in the tensile strength of pTi pretreated using a silane coupling agent before PMMA filling is greater than that of the non-pretreated pTi because the stress concentration near the pores may be reduced by the improvement in the interfacial adhesiveness between the titanium particles and the PMMA. In contrast, the effect of the PMMA filling on the Young's modulus of pTi is smaller than that on the tensile strength because the Young's modulus of PMMA is considerably lower than that of pTi. Further, tensile strengths and Young's moduli comparable to the tensile strength and Young's modulus of the human bone are successfully obtained in the case of some pTi/PMMA samples.