Initial development of preceramic polymer formulations for additive manufacturing

Abstract

Three preceramic polymer formulations for potential use in additive manufacturing technologies were investigated. The polymeric precursors include an allyl hydrido polycarbosilane (SMP-10), a mixture of SMP-10 with a reactive ester (1,6-hexanediol diacrylate, HDDA), and a polydimethylsiloxane (4690A/B). The SMP-10/HDDA proved to have outstanding photo-curing properties, high-resolution printing, and the ability to easily transform into the silicon carbide phase. The same polymeric mixture showed the lowest viscosity value which is preferred in vat additive manufacturing. Thermogravimetric analysis showed that, after pyrolysis to 1350 °C, the polydimethylsiloxane polymer showed the highest onset decomposition temperature and the lowest retained weight (52 wt%) while the allyl hydrido polycarbosilane showed the lowest onset decomposition temperature and highest retained weight (71.7 wt%). In terms of crystallography, X-ray diffraction and microstructural results showed that the ceramic matrix composites contained both silicon carbide and silicon oxycarbide. Overall, the results are very promising for the fabrication of ceramic materials using additive manufacturing technologies.