Development and characterization of novel photopolymerizable formulations for stereolithography

Novel photopolymerizable formulations, able to photopolymerize with a dual mechanism (cationic and radical), were developed and characterized as potential resins for stereolithography (SL) process. The influence of the presence of organically modified boehmite nanoparticles on the properties of the photopolymerizable mixtures was also analyzed. The main properties required for a liquid SL resin are a high reactivity and a low viscosity. All of the experimental formulations produced, even in the presence of boehmite nanoparticles, are able to satisfy these significant requirements. Physical-mechanical and thermal properties of the photocured samples, obtained starting from the experimental formulations, were finally measured. The cured nanocomposite bars show a high transparency, confirming the good dispersion of the nanofiller in the polymeric matrix and possess improved glass transition temperature (T) and mechanical performances, compared to the unfilled system and to a commercial stereolithographic resin. These results suggest the possibility of using the novel nanofilled photopolymerizable suspensions in the stereolithographic apparatus to build, not only esthetical, but also functional prototypes.