Liquid silicone rubber with uniformly dispersed nanosized silica for the preparation of SiOC ceramics

Abstract

Facile preparation process and the readily available raw materials are favorable for scale-up of SiOC ceramics. In our work, Liquid silicone rubber (LSR) was creatively developed to prepare silica-enhanced SiOC ceramics by injection molding. Benefiting from the excellent processability of the LSR precursor, complex ceramic devices could be easily prepared. The ceramics showed a microstructure similar to that of a tough asphalt/gravel road material, with silica nanoparticles well dispersed as a reinforcement phase within a continuous phase of SiOC. Compared with the pure SiOC ceramic, the addition of silica can increase the ceramic yield from 5.8% to 73.8%, and the flexural strength can be increased from an unmeasurably low value to 282.7 ± 24.2 MPa. Additionally, by varying the pyrolysis temperature and silica content, the porosity of the ceramic morphology could be tailored to achieve specific surface areas of 13–501 m2/g. The optimal sample with both good flexural strength (216.3 ± 13.5 MPa) and high specific surface area (293 m2/g) contained 20 wt% silica and was pyrolyzed at 1000 °C.The SiO2/SiOC samples are referred to as S-X%-Y, where S denotes silica, X is the silica content (wt%), and Y is the pyrolysis temperature (°C).