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Process-Based Model of Mixed-Matrix Membrane
Čapek, P. ; Hejtmánek, Vladimír ; Veselý, M. ; Sysel, P. ; Kočiřík, Milan ; Brabec, Libor ; Zikánová, Arlette ; Bernauer, B. ; Fíla, V.
The focus of this contribution was on the formulation and verification of a process-based model of the mixed-matrix membrane that consisted of the polyimide matrix synthesized from the monomers 4,4’-(hexafluoroisopropylidene)diphtalic anhydride and 4,4’-oxydianiline, and silicalite-1. When a solution of a polyimide precursor in N,N-dimethylformamide was ready, silicalite-1 particles were dispersed in the solution and the dispersion was subsequently cast on a Teflon support plate. An initial mass ratio of silicalite-1 and polyimide was about 1:1. After solvent removal, the films were heated in subsequent steps up to 230°C for two hour. From a process-based model point of view, a key operation of the entire synthesis was slow sedimentation of silicalite particles in the viscous solution. Preliminary observation of 2D cuts through the solid membrane in a scanning electron microscope revealed that there were a lot of contacts among the silicalite particles. Therefore, a sequential (ballistic) deposition algorithm, well representing sedimentation in a low-energy environment, was used to create an off-lattice model of spatial distribution of the silicalite particles in the polyimide matrix.
Plný tet: SKMBT_C22012102413461 - PDF Plný text: content.csg - PDF
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Porous composites based on siloxane resin for hard tissue replacements
Suchý, T. ; Balík, Karel ; Sochor, M. ; Černý, Martin ; Hulejová, H. ; Pešáková, V.
A composite material based on polysiloxane and first on glass fabrics was prepared. The composite samples were prepared with controlled open porosity, the sizes of which were in the range: i) 0,2-0,4 mm, ii) 0,4-0,6 mm, and iii) >0,6 mm. For further improvement of osseointegration, a powder hydroxyapatite, particle size of 0,005 mm in the amount of 10 wgt %. The effects of surface treatment and hydroxyapatite matrix additives on osseointegration were studied by methods in vitro and in vivo.
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