Mechanical Properties of Bioactive Hybrid Organic/Inorganic Aerogels
Hybrid silica-organic polymer aerogels based on tetraethoxysilane (TEOS) have been synthesized, polydimethylsiloxane (PDMS) and methyltriethoxysilane (MTES) have been used as organic phases. Synthetic wollastonite powder was added as bioactive phase. The composites were prepared by dispersing wollastonite powder in the sol with the assistance of high power ultrasounds to control the gelling time. Wet composites were dried under supercritical conditions of the solvent. The mechanical characterization was performed by uniaxial compression and by nanoindentation. Young`s modulus from uniaxial compression increase from 5 MPa to 100 MPa for increasing MTES content and also rupture modulus was enhanced from 0.85 MPa to about 50 MPa, so the incorporation of cross linkers in this kind of aerogels, was proven to enhance the mechanical resistance. However the inclusion of wollastonite powders provokes a dropping of the Young’s modulus and hardness. All the composites showed bioactivity by the formation of an apatite layer when immersed in Simulated Body Fluid (SBF).
Nicolás de la Rosa Fox
V. Morales-Flórez et al., "Mechanical Properties of Bioactive Hybrid Organic/Inorganic Aerogels", Key Engineering Materials, Vol. 423, pp. 155-160, 2010