Preparation And Characterization Of Nano-SiO₂ And Go Reinforced Poly （Ether-Ether-Ketone） Composites

In recent years,bioactive nanocomposites have attracted more and more attention in hard tissue repair materials.As a special engineering plastic,Poly（ether-ether-ketone）（PEEK）has excellent mechanical properties,thermal stability,radiation resistance,and good biocompatibility.It is considered as one of the ideal candidates for hard tissue repair.However,its poor interface with surrounding tissue after implantation limits its application in clinical complex tissue repair due to the chemical and biological inertness of pure PEEK.Therefore,it is of great significance to improve the mechanical properties and surface bioactivity of PEEK-based composites using inorganic nanomaterials.Nano-SiO₂ nanoparticles with good biocompatibility are widely used as inorganic filler to improve the mechanical properties and surface hydrophilicity of the composites.However,the high surface energy of nano-SiO₂ makes it easy to agglomerate in the composite matrix,which affects the improvement of the properties of the composites.In this study,a series of the PEEK/nano-SiO₂ composites are firstly prepared,and the effects of different contents of nano-SiO₂ on the mechanical and thermal stability of PEEK/nano-SiO₂ composites are studied.Then,nano-SiO₂ modified by 3-aminopropyltriethoxysilane（m-SiO₂）is used to prepare PEEK/m-SiO₂composite,and the mechanical properties of PEEK/m-SiO₂ composite is studied.To improve the interfacial combination between PEEK and nano-SiO₂,graphene oxide（GO）is introduced as interface reinforcing material.On the one hand,the conjugated structure composed of sp² hybrid carbon atoms in the GO molecular structure can combine with the benzene ring in the PEEK molecular segment throughπ-πinteraction;on the other hand,GO can provide anchoring sites for nano-SiO₂ by oxygen-containing functional groups.Therefore,GO nanosheets reduce not only the agglomeration of nano-SiO₂,but also improve the adhesion between GO and PEEK matrix.Experimental results show that nano-SiO₂ with different contents significantly improves the mechanical properties of PEEK/nano-SiO₂ composite,and the PEEK/nano-SiO₂ composite with a 30%content of nano-SiO₂ has the best mechanical properties,the maximum tensile strength of PEEK/nano-SiO₂ is 95.9±2.1 MPa.The highest tensile strength of PEEK/m-SiO₂ composite is approximately 103.0±3.6 MPa.The addition of GO nanosheets also significantly improves the mechanical properties of the composites.When the content of nano-SiO₂ and GO is 30%and 1.5%,the tensile strength,flexural strength,and Young’s modulus of PEEK/nano-SiO₂/GO composite are approximate 101.5±1.7 MPa,120.1±5.1 MPa,and 4617±82.0 MPa,respectively,which is approximate 10.8%,17.7%,and 39.5%higher than that of pure PEEK.The mechanical properties of the composites decrease with a further increase of GO content.The water contact angle test shows that the surface hydrophilicity of PEEK/nano-SiO₂/GO composites is higher than pure PEEK.The simulated body fluid experiment shows that the composite effectively promotes the mineralization of hydroxyapatite on its surface,implying that it has good bioactivity for promoting bone repair.These results provide an essential basis for developing novel medical implants based-on PEEK/nano-SiO₂/GO composites and their applications in clinical complex tissue repair.