In-Situ Real Time Monitoring of the Polymerization in Gel-Cast Ceramic Processes

Abstract

The method of gelcasting requires making a mixture of a slurry of ceramic powder in a solution of organic monomers and casting it in a mold. Gelcasting is different from injection molding in that it separates mold filling from setting during conversion of the ceramic slurry to a formed green part. In this work, nuclear magnetic resonance (NMR) spectroscopy and imaging has been used for in-situ monitoring of the gelation process and gelcasting of alumina. 1H N M R spectra and images are obtained during polymerization of a mixture of soluble reactive acrylamide monomers. Polymerization was initiated by adding an initiator and an accelerator to form long-chain, cross-linked polymers. Multidimensional NMR imaging was utilized for in-situ monitoring of the process and for verification of homogeneous polymerization. Comparison of the modeled intensities with acquired images shows a direct extraction of T1 data from the images.