Commercial light-sensitive resins for Rapid Prototyping of cellular materials are often unsuitable for different molding techniques because removal of the mold uses thermal decomposition at temperatures of up to 600°C. In this study, a resin formulation based on water-soluble polymers was developed and evaluated regarding its usability as sacrificial mold material. The base monomer dimethylacrylamide gave fast curing and excellent polymer solubility. Methacrylic acid was found to be a useful comonomer to improve mechanical strength and feature resolution. The latter criterion was also improved by adding poly(vinyl pyrrolidone) as filler and by using a hydrolytically cleavable crosslinking agent such as methacrylic acid anhydride.

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Many biological materials (e.g. wood, cork, bone,. . .) are based on cellular designs, since cellular architectures offer the possibility to optimise the properties (stiffness, density, strength,. . .) of a structure according to the environmental conditions the structure is exposed to. By using Rapid Prototyping it is possible to fabricate cellular materials on a similar size scale as in natural material-structures. By using appropriate moulding techniques, these structures can be fabricated out of a wide variety of materials (polymers, ceramics, composites). In this work, several RP techniques are investigated regarding their suitability for the fabrication of cellular solids. The main focus is on using direct light projection (stereolithography) in combination with gelcasting as moulding technique. Besides using commercial light-sensitive resins, a class of newly developed water-soluble resins has been evaluated regarding its usability as sacrificial mould material.

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