Additive Manufacturing of Filled and Unfilled Bio-Photopolymers

Abstract

Vinyl-ester based monomers have shown minimal cytotoxic behaviour during invitro tests which could lead to an alternative to traditional used (meth)-acrylate-based compositions in biomedical applications. Even more promising, network densities of these photopolymers can be modified by adding multifunctional thiols resulting in biodegradable polymers with nontoxic degradation products. Biodegradability as well as reactivity during the polymerisation process can be controlled by the amount of added thiol. In a next step manufacturing of scaffolds or implantable structures out of these polymers is of great interest. This work is dealing with attempts to structure such polymers by means of additive manufacturing processes or 3D-printing. Layer by layer structuring with an overall resolution of 25µm was achieved using DLP-technologies (digital light processing). Different biodegradable formulations were tested with respect to flexural strength and modulus as well as impact strength. Further improvement was achieved by adding biocompatible glass microfibers. Resulting composites were also structured successfully using 3D-printing techniques, showing a flexural modulus around 1GPa and flexural strength up to 36MPa. The impact strength (Charpy) of unfilled bio-photopolymers was measured to be around 17kJm-2.