CONICET | Buscador de Institutos y Recursos Humanos

The nature has become an innovation model for the design of porous ceramic structures. In particular, wood tissue is considered as a potential candidate to be used as template to generate different micro, meso and macro-cellular ceramic structures because it presents a hierarchical porous microstructure and unique microstructure-properties relationships. Several processing routes which include in a variable sequential order the infiltration of a carbon template with different chemical agents and the pyrolysis in controlled atmosphere. However, an alternative processing route that has been little studied, which is based on the infiltration of wood templates with a silicon-based preceramic polymer and subsequent pyrolysis in inert atmosphere, is presented as a promising way for the development of porous biomimetic SiOC-based ceramics. In this work, a polysilsesquioxane (MP-POSS; silicon-based preceramic polymer) with high concentration of Si-OH groups synthetized by condensation of 3-methacryloxypropyl-trimethoxysilane (molar ratio HCOOH/Si=0.055; 60°C, 1.5 days) and characterized by density measurement, ATR, RMN and DSC, was used as infiltration agent of poplar templates (native and physically activated by Soxhlet extraction; diameter=2.0cm, length =1.5cm), which were characterized by density and porosity measurements, and optical microscopy and SEM. The infiltration of the templates was carried out under vacuum at room temperature. The infiltrated samples were cured at 135°C, 3h and characterized by measurements of weight gain, density and porosity, and by ATG and SEM/EDS. The pyrolysis was performed at different temperatures (1000°C-1500°C) in N2 atmosphere, and the obtained porous biomimetic SiOC-based ceramics were characterized by XRD, SEM/EDS, FTIR and Raman.