Papers by Keyword: Macroporous Ceramic

Abstract: Aluminium powder was used as foaming agent in the production of macro-porous alumina ceramic. The porous ceramic material was developed by mixing an appropriate composition of cement, aluminium powder (Al), alumina (Al₂O₃), calcium oxide (CaO), gypsum (calcium sulphate dehydrate, CaSO₄.2H₂O), silica powder and deionized water. Different compositions of porous ceramic were produced at 2wt.%, 3wt.% and 4wt.% of aluminium powder. Their mechanical properties and macro-porosity structural of the porous ceramic material were analysed and compared. It is determined that the optimal properties of porous ceramic material were found at 3wt.% of aluminium powder and degraded drastically at 4wt.%. This phenomenon is due to the chemical reaction between the aluminium powder and DI water in which they form aluminium oxide that promotes the strength of the material but at the same time, more pores are created at higher reaction rate between these two fundamental materials.

Abstract: Macroporous polymer-derived SiCN ceramics are fabricated directly by mixing polysilazane precursors followed with crosslinking and pyrolysis. Two kinds of polysilazanes namely polyvinylsilazane and polyhydrosilazane are mixed, crosslinked by 2, 2-Azo-bis-isobutyronitrile to form resins before pyrolyzed to form ceramics in argon flow at 1000°C. The density of the SiCN ceramic is 1.65 g/cm³ with corresponding porosity of 30 % compared to dense SiCN ceramics. SEM images show that the ceramics possess high porosity and homogeneous honeycomb-like macropores of ~2 μm. The porous SiCN exhibits good mechanical property with Vicker hardness of 11-13 GPa under a load of 0.2 kg.

Abstract: The potential of porous materials for applications in the medical, engineering and pharmaceutical areas has been widely reported. Several processing techniques have contributed to the progress in research involving porous biomaterials. To this purpose, a globular protein based (i.e. ovalbumin) consolidation approach has been proposed. In the present study, a porous hydroxyapatite: -tricalcium phosphate - biphasic ceramics (BCP), was processed by direct consolidation using the protein-action technique. The processed porous ceramic exhibited appropriate pore configuration in terms of size, morphology and distribution. BCP cylindrical samples were implanted in male rabbits tibia to the evaluation of the initial biocompatibility and osseointegration for a 30 days period. The morphological analyses, optical microscopy and scanning electron microscopy evaluated the osseointegration. A rough surface pattern displayed by the ceramics seemed to have improved cell adhesion and proliferation processes. Furthermore, the open porosity of samples was an essential requirement for a suitable bone-implant osseointegration. In conclusion, this study revealed that the porous matrices obtained, promoted suitable development for bone tissue growth and also properties for osseoconduction and osseointegration.

Abstract: In this paper, Nanoslurry-ZrO2 were added into alumina powders to improve the bending strength of macroporous Al2O3 Ceramic sintered at 1550°C, 1600°C, 1650°C corresponding for3h each in air, respectively. The results show that the bending strength of porous alumina ceramic was simultaneously greatly influenced by various ZrO2 contents. When ZrO2 content is 2wt%, the maximum bending strength value of sample heated at 1650°C was observed, which achieves to 50 MPa. And the maximum bending strength value of any sample also exists at 1650oC. By SEM analysis, many fine ZrO2 particles with high activity surface form a neck bonding which is beneficial to the improvements of bending strength.

Abstract: Calcium phosphate ceramics are widely used as bone substitutes since they are biocompatible and bioactive. Given that their chemical composition is close to natural bone, calcium phosphate ceramics are promising bone substitute materials in orthopaedics, maxillofacial surgery and dentistry. Hydroxyapatite (HA) and tricalcium phosphate (TCP) are the most commonly used calcium phosphates, because their calcium/phosphorus (Ca/P) ratios are close to that of natural bone and they are relatively stable in physiological environment. Furthermore, other critical parameters must be accomplished when designing a biomaterial for bone regeneration, namely: pore size, shape and interconnectivity [1]. Porosity is one of the most important factors since it influences the adhesion, migration nutrient supply and ultimately, proliferation of mesenchymal stem cells. In this study, HA scaffolds with controlled porosity were obtained and their capacity to support human and rat mesenchymal stem cells attachment and proliferation was evaluated.