Rheological Study of 3D Printed Semi Interpenetrated Networks

The vat photopolymerization 3D printing technique enables the fabrication of complex and precise geometries that exceed the capabilities of conventional polymer processing methods, while reducing the overall waste generated during production. Despite these advantages, the resulting products often exhibit densely cross-linked and brittle polymeric networks, what is a problem for their reprocessing. This work takes advantage of a strategy developed in the group [1] to synthesize high molecular weight and low viscosity resins based on latexes, suitable for printing. After printing with this strategy, a chemical cross-linked network is obtained, in which the latex particles are encapsulated. Furthermore, after drying of the printed parts, the polymeric chains diffuse and form a second physical network of entanglements, giving rise to a semi-interpenetrated network (SIPN). In this work we present the rheological study of these SIPN's, where we seek to understand how the two types of networks (both the physical and the chemical) affect the rheological and mechanical properties of the final material, and for that the viscoelastic properties of the networks have been studied. Finally, in order to study the reprocessability of the systems melt viscosity measurements have played a key role.