New Low-Toxic PEG(200)DMA/AM Gel System for 3YSZ Gel-Casting

Abstract

Gel-casting is promising in fabricating uniform and complex-shaped ceramic body, but it is confined in industrial application for the neurotoxic acrylamid (AM) gel system. Ether-contained oligomer poly(ethylene glycol)(200) dimethacrylate (PEG(200)DMA) with methacrylate end-group on either side of the long chain can act as cross-linking agent in free radical polymerization to form branchy gel network structure, which improves the green body strength. In this study, low-toxic PEG(200)DMA was chosen as the main binder and crosslinker and small dosage AM was applied to adjust the viscosity of the ceramic slurry to gel-cast 3YSZ (PEG(200)DMA: AM = 4:1, mass ratio). Influence of monomer concentration, dispersant concentration and solid loading on the rheological behavior of the slurry and the flexural strength of the green body were investigated using aqueous PEG(200)DMA/AM gel system to gel-cast 3YSZ. The results show that the flexural strength of green bodies notably increases with the increasing of monomer concentration and reaches high up to 14.4 MPa when gel-cast 3YSZ ceramics using PEG(200)DMA/AM gel system with appropriate amount of PAA-NH4, monomer and solid loading. This gel system obviously reduces the toxicity of the conventional AM system and, at the same time, ensures high flexural strength of green bodies.