Stereolithography based additive manufacturing of high-k polymer matrix composites facilitated by thermal plasma processed barium titanate microspheres

Stereolithography (SL) is a promising 3D printing method for the fabrication of high dielectric constant polymer matrix composites (high-k PMCs) because of its high geometric accuracy and few manufacturing defects. However, the presence of ceramic filler destroys the fluidity and transparency of high-k PMCs, reducing their 3D printability. In this study, we fabricated barium titanate microspheres (BT-S) to facilitate the SL-based 3D printing of high-k PMCs using radio-frequency thermal plasma spheroidization (RF-TPS) technology. Experimental results showed that the prepared BT-S particles have spherical shape, smooth surface, large particle size, improved mechanical strength and higher purity, which lead to the enhancement in the 3D printability of UV curable high-k composites: i) the employment of BT-S significantly reduces the apparent viscosity and yield stress; and ii) the UV curing depth increased by 542% maximum. As a result, high-k composites were successfully printed using digital light processing (DLP) technique under low UV light energy. Moreover, the increase of dielectric constant was experimentally verified, which is explained by electrostatic energy increment according to finite element method (FEM) simulations. This study provided an effective approach (i.e.