Gelcasting in moulding of ceramic powders with application of new monomers
|Paulina Bednarek , Mikolaj Szafran , Tadeusz Mizerski|
Warsaw University of Technology, Faculty of Chemistry, Noakowskiego 3, Warszawa 00-664, Poland
In fabrication of ceramic elements widely applied methods are still injection moulding and slip casting, but both techniques have serious limitations. In order to overcome these limitations the colloidal processes are investigated. One of the extensively studied forming method is gelcasting, which combines conventional moulding from slips with polymer chemistry. Gelcasting process allows obtaining high-quality, complex-shaped ceramic elements by means of an in situ polymerization, through which a macromolecular network is created to hold ceramic particles together.
The key role in the process plays selection of a suitable monomer, which is able to provide high mechanical strength of a gelled part. The applied monomers must perform a series of conditions: they must be water soluble, non-toxic and high mechanical properties must be achieved by as low as possible concentration of a monomer in a ceramic slurry.
For many years commonly applied monomer in gelcasting method was acrylamide, which has probably cancerogenic action, therefore recently acrylic monomers, such as 2‑hydroxyethyl acrylate started replacing hazardous acrylamide.
The research made by authors concentrate on the synthesis and application of new water-soluble and non-toxic monomers on the basis of monosaccharides. The presence of many hydroxyl groups in a monomer molecule allows forming hydrogen bonds in a polymer network. As a result a cross-linked polymer network is received and no external cross-linking agent is necessary to obtain a rigid ceramic part. This fact allows reducing the quantity of added organic substances to the ceramic slurry and the amount of gases released to the atmosphere during polymer burnout.
This work was partially financially supported by Faculty of Chemistry Warsaw University of Technology: Project no. 504G/1020/0787
Presentation: Poster at E-MRS Fall Meeting 2008, Symposium I, by Paulina Bednarek
See On-line Journal of E-MRS Fall Meeting 2008
Submitted: 2008-05-12 15:40 Revised: 2009-06-07 00:48