Polymer-derived SiOC ceramic lattice with thick struts prepared by digital light processing

Compared with the photosensitive ceramic slurry containing ceramic particles, the photosensitive preceramic polymer was more suitable for the digital light processing (DLP) printing of ceramics. However, the strut thickness of the DLP 3D printed polymer-derived ceramics is always limited due to the serious deformation caused by the aggregation of the enormous by-product gases during the pyrolysis process. Herein, a novel photosensitive epoxy-acrylic siloxane was employed as the matrix for the digital light processing and a nonphotosensitive liquid siloxane was introduced as an additive to generate micro-sized channels during pyrolysis, consequently ensuring that the by-product gases can be smoothly released through these channels. With the increase of the pyrolysis temperature, those micro-sized channels would shrink, leaving some nano-pores (or uneven surface) in the pyrolyzed SiOC components. Results show that the DLP 3D printed SiOC lattices with the addition of liquid siloxane show a better macro-appearance and macro-mechanical property with scarifying its micro-hardness. We believed that the method of promoting the release of by-product gases by introducing a nonphotosensitive siloxane can be further applied to other DLP 3D printed polymer-derived ceramics.