Porous TiO2 particles as reinforcing fillers for 3D printing thermosetting polymers

Abstract Synthesizing high-performance particle composites often entails grappling with poor filler dispersions and highly complex processes. Therefore, the need for inexpensive workable fillers for producing such composites with simple equipment is becoming increasingly important. Herein, we report on the fabrication of lepidocrocite (a 2-dimensional polymorph of titania), porous, mesoscopic particles, PMPs, comprised of 1D strands of self-assembled 1D titanate, reinforced polymer composites featuring a flexible acrylic-based, commercially available resin – using a desktop UV-light operated 3D printer. Uniform particle dispersion within the monomer is achieved by high-shear mixing. Adding 2 wt.% filler increased the tensile yield stress, TYS, from 31 (neat polymer) to 55 MPa, while maintaining strains to failure of ~ 10%. At 5 wt.% loading, the elastic moduli increased from 1.75 GPa to ~ 2.4 GPa. The enhancement in properties is most probably related to the porous nature of our meso-particles that the polymer penetrates, yielding a very strong interface. This work is significant in that it presents a new way to couple strength and toughness in thermosets, a commonly reported limitation in this class of polymers. This is especially true given the ease, scalability, and low cost of manufacturing PMPs.