A Synergistic Low-Toxicity Gelcasting System by Using HEMA and PVP

A new low-toxicity gelcasting system with a 2-hydroxyethyl methacrylate (HEMA) monomer was applied for casting of alumina ceramics. Polyvinyl pyrrolidone (PVP) was adopted for modifying the homogeneity of the PHEMA (poly-HEMA) gel. The rheological properties of alumina suspension in the HEMA–PVP premix solution were studied. After preparation of a concentrated alumina suspension, homogenous alumina green body with a relatively high strength of about 19 MPa could be formed through the PVP-modified HEMA system. Dense complex-shaped ceramic parts can be successfully produced through the system. Besides, the surface exfoliation phenomenon that seems inherent to the acrylamide gelcasting system could also be eliminated by using the PVP-modified HEMA system. Analysis of the interaction of HEMA and PVP suggested that the improved microstructure and strength homogeneity, as well as the elimination of surface exfoliation in the new system, should be attributed to the intermolecular hydrogen bonding formed between PHEMA and PVP molecules.