Bioactive carbon fibres/pseudowollastonite composites for bone surgery application

Teresa Gumuła, Marta Błażewicz, Czesława Paluszkiewicz Akademia Górniczo-Hutnicza, Wydział Inżynierii Materiałowej i Ceramiki, al. Mickiewicza 30, 30-059 Kraków, Poland

Quarterly No. 1, 2008 pages 41-46

DOI:

keywords: carbon-ceramic composites, polymeric precursors, polysiloxanes, pseudowollastonite, carbon fibres, bioactivity

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abstract In this work pseudowollastonite Ca3(SiO3)3 matrix composites reinforced with carbon fibres, which may be used for bone reconstruction, were investigated. The composites were obtained by new way, namely impregnation of carbon fibres with active fillers-containing polysiloxane polymer (so-called preceram). As received composites were then subjected to controlled heat treatment at 1000C. Two types of composites differing in fibres spatial arrangement, namely unidirectional (1D) and multidirectional (2D/1D/2D), were prepared. The ceramic composites were analysed by means of Fourier transform infrared spectroscopy (FTIR). Their structure was carried out on XRD diffractometer. Mechanical properties, namely bending strength and Young’s modulus of the composite samples were investigated in three point bending test. The bioactivity was determined in in vitro conditions, by immersing of composite samples in simulated body fluid (SBF) during the time of 8 and 16 days. After that test surfaces of composites were studied by scanning electron microscope (SEM) and EDS point analysis. FTIR spectra of composites indicate that after heating process, in both cases, pseudowollastonite i.e. ring silicate of the formula Ca3(Si3O9), is formed. XRD analysis reveals that heat treatment products of carbon fibres and active fillers-containing polysiloxane precursor, contain carbon and pseudowollastonite Ca3(Si3O9). The crystallite sizes of pseudowollastonite, calculated from diffraction peak using the Scherrer’s equation, are in case of 1D composite 52 +/– 21 nm and in case of 2D/1D/2D composite - 47 +/– 11 nm. Bending strengths of as received composites are rather low. Higher bending strength represents 1D composite. This composite can be applied as an implant in maxilofacial surgery. Both composites posses Young’s modulus values adequate for bone surgery applications. Different spatial arrangement of carbon fibres influences on fracture toughness of composites. Such obtained composites demonstrate bioactivity in in vitro conditions. On 2D/1D/2D composite surface already after 8 days of immersing in SBF calcium phosphate precipitated. The results presented in this work indicate that heat treatment at 1000C of composites reinforced with carbon fibres, which matrices were obtained from active fillers- containing polysiloxane polymer, is a new method leading to receiving of bioactive carbon fibres/pseudowollastonite composites. Future studies on such composites should be focused on investigation of their biological properties and on further improvement of their bending strength, what could widen their application as constructive implants.