Binder Formulation in EVA-wax system for Fused Deposition of Ceramics

Abstract

Blends in the ethylene vinyl acetate (EVA) - wax system have been evaluated as potential binders.to be used in fused deposition of ceramics (FDC). In order to obtain good handling strength, it was indicated that the melting point of the polymer needs to be lower than that of the wax. In this context, it was shown that the melting point of the EVA decreases as the vinyl acetate content in the copolymer increases. By measuring the viscosity as a macroscopic property, it was shown that 20 % vinyl acetate-containing EVA is miscible in microcrystalline wax up to, atleast, 30 %.Binders used in FDC need to have low viscosity and it was pointed out that the slumping can be one main problem associated with binders with low viscosity. Thus, thermolysis of wax at low temperature is suggested as a solution. The volumetric thermal expansion and melt strength of an EVA-wax blend were displayed as a function of temperature, in the form of a penetration test.