Melt Extruded SiC-acrylonitrile Fibers for SiC Yarn Domestic Production

Currently, the majority of silicon carbide (SiC) yarns are produced and controlled by foreign entities. For decades, sourcing continuous SiC fibers has been a major struggle for US-based companies looking to incorporate them into ceramic matrix composites (CMCs). To combat these issues, utilizing discontinuous SiC fiber for yarns has been gaining interest. The prospect of discontinuous SiC fiber yarns can lead to improved drapability, processing, and tunable thermal properties for a wide range of domestically produced CMCs. It is the goal of this Phase I program to develop a melt extrudable SiC-acrylonitrile system to produce C/SiC fibers. NanoSonic will develop a copolymer, acrylonitrile system that will be melt extruded via screw-based extrusion. Manipulating the rheology of the copolymer with melt-modifiers will allow NanoSonic to tune the viscosity to meet parameters of screw-based extrusion. In addition, NanoSonic will incorporate SiC discontinuous fibers at high loadings into the copolymer system that will permit the transfer of the SiC properties to the C/SiC fiber once carbonized. NC State’s Wilson College of Textiles, a US leader in textile engineering, and Free Form Fibers, a domestic producer of SiC discontinuous fibers, are in support of this program.