Flexible and Porous Nonwoven SiCN Ceramic Material via Electrospinning of an Optimized Silazane Solution

The processing of nonwoven porous ceramics by combining the polymer-derived ceramic (PDC) route with electrospinning offers an excellent strategy for developing new porous ceramic structures. Currently, the manufacturing of nonwoven porous materials from preceramic polymers is conducted by trial and error approaches. The necessity to predict the e-spinnability conditions from properties assessment offers a potential tool to control the manufacture and the resulting material morphology. This work assesses the relationship between the preceramic polymer solutions and the resulting electrospun nonwoven morphology. For this, a commercially available liquid oligosilazane (Durazane 1800) is selectively cross-linked to achieve a reliable and spinnable preceramic polymer (HTTS), which is then dissolved in tetrahydrofuran (THF). Based on the investigation of the rheological behavior of various polymer concentrations, three different polymer solution regimes (diluted, semidiluted, and concentrated) are identified and correlated with the resulting morphology of the e-spun material (spherical particles, beaded fibers, and seamless fibers). After the pyrolysis, the nonwoven ceramics manufactured from the solution with 65 wt% of HTTS is converted to a SiCN ceramic nonwoven with 86% of open porosity, profiling as a promising candidate for developing high-performance filter systems and catalytic supports in harsh environments.