Evaluating Extrusion Deposited Additively Manufactured Fiber-Reinforced Thermoplastic Polymers as Carbon/Carbon Preforms

Although development of high char-yielding polymers has reduced the manufacturing costs of carbon/carbon composites associated with multiple densification cycles, manufacturing highly customized complex-shaped carbon/carbon composites can still be expensive due to molds/tooling surfaces used by traditional preform production techniques. In this study, we explored whether extrusion deposition additive manufacturing (EDAM) could be used as a mold-less approach to manufacturing complex-shaped carbon/carbon composites. The thermogravimetric analysis and coupon distortion results of several short carbon fiber-reinforced thermoplastic polymers used for 3D printing were investigated, including polyphenylene sulfide, polyetherimide, poly sulfone, polyether ether ketone, and polyether sulfone. Although polyetherimide had the highest char yield \(\left(57 wt.\%\right)\), carbon fiber-reinforced polyphenylene sulfide was the best preform for manufacturing complex shapes because of its dimensional stability, with carbonized strains of \(-4.18\times{10}^{-2}\) and \(1.82\times{10}^{-1}\) at 1 \(^\circ C/min\) in the 1- and 3- direction, respectively, after heat treating to \(900\;^\circ C\). The distortion results of more complex shapes showed that EDAM can be a practical alternative over more traditional preform production techniques for manufacturing complex-shaped carbon/carbon composites.