Polymer ionomers for rapid prototyping and rapid manufacturing by means of 3D printing

The powder blend of poly(acrylic acid) (PAA) with zinc oxide or zinc oxide/magnesium oxide was applied successfully to produce zinc polycarboxylate during the 3D dispensing of an aqueous ink by means of 3D printers (Z402(TM) from Worporation and Deskmodeler(TM) from brat Company). The layer-by-layer inkjet printing afforded zinc ionomer 3D objects with excellent water resistance, no inherent color formation and high mechanical and dimensional stabilities. In contrast to the 3D printing of conventional powders such as starch/cellulose/dextrose blends, poly(vinyl alcohol) (PVA) or plaster, no postprinting treatments were required. Excellent dimensional accuracy of the models, as evidenced by very small deviation of the dimensions from mechanical properties improved with increasing PAA content, ink amount (saturation value), decreasing particle size of the sintered zinc oxide cerarnic. At high PAA content >7wt.-%, post-treatment with aqueous zinc acetate solution improved the mechanical properties. The setting time of the zinc cements shows no significant effect on the mechanical properties, but on the water resistance of the models. The porosity of the 3D objects, measured by means of X-ray microtomography (mu-CT), had profound impact on the variations of the mechanical properties of the 3D objects prepared by 3D printing processes.