A Pyrolysis Cycle Optimization Framework for Evaluation of Novel Carbon Precursors

Over the past twenty years, Materials Research & Design, Inc. (MR&D) has been involved on many programs focused on the simulation, development, and study of various pyrolysis processes.ĀThe initial pyrolysis of polymer-derived high-temperature composites is a process step during carbon-carbon (C/C)Ā and ceramic matrix composite (CMC) fabrication that poses a significant challenge to the material system, particularly ones utilizing 2D continuous fiber reinforcement. The decomposition induced stresses which result from pore pressure generation and conversion of the matrix from a cured polymer to a porous carbonaceous char can be severe enough to induce delaminations in a component. To combat this, many fabricators utilize conservative, lengthy pyrolysis cyclesĀwhich areĀapplied to components agnostic of geometry or layup architecture. As domestic manufacturers of C/C and CMCsĀtransition from prototyping operations to production, there exists a need not only to accelerate the rate at which components are produced, but to ensure that the existing processes are not being changed in a way that is deleterious to the manufacturability or structural capability of the resulting material.ĀMR&D and their program partners propose an effort to develop a computational framework for the optimization of C/C pyrolysis cycles. Despite being focused on C/C, the approach will be equally applicable to CMC manufacturers utilizing similar process routes. The Phase I STTR program proposed herein will focus on two carbon precursors.ĀOne resinĀhas a long legacy as a carbon precursor, represents multiple incumbent hypersonic thermal protection system (TPS) solutions, and has been extensively characterized through pyrolysis across various DoD-funded efforts.ĀIn contrast, the second resin under considerationĀis relatively novel, showing promise as a potential high char yield alternative to the incumbent, but has not yet been thoroughly assessed or characterized for manufacturability as a C/C composite. MR&D will work closely with the National Institute for Aviation Research (NIAR) at Wichita State University (WSU) ¢ the Phase I Research Institute (RI) ¢ to characterize various thermo-poro-elastic propertiesĀthrough initial pyrolysis.ĀThe measured material properties through decomposition will serve as critical inputs to the computational analyses performed by MR&D.ĀA feasibility demonstration of the proposed pyrolysis cycle optimization methodology would be incomplete without preliminary validation. To this end, MR&D has enlisted the support of Kratos SRE (KSRE) (Birmingham, AL) to perform pyrolysis trials on flat panel materials. These trials will employ the cycles defined by MR&D and the resulting materials will be assessed mechanically and microstructurally. By these metrics, the Phase I team will assess the degree of material improvement over a baseline pyrolysis cycle, and establish a path forward for transition and commercialization in Phase II.