Effects of Low-Temperature Treatment on the Properties of Commercial Preceramic Polymers

Low-temperature, pre-gelation, thermal treatment of ceramic precursors is a common preliminary step in the polymer infiltration-and-pyrolysis-based processing of ceramic matrix composites (CMCs). A variety of polymer properties can be modified using this approach, the most important being molecular weight distribution, viscoelastic state, solidification behavior, and ceramic yield. In this work, the effects of thermal treatment on the processing properties of two commercial preceramic polymers, StarPCS™ SMP-10 and KiON Ceraset® PSZ-20, have been investigated. It was determined that the volatilization, molecular chain scission, and polymerization phenomena occurring during treatment, lead to increased viscosity, higher molecular weight, lower temperature of solidification onset, and improved ceramic yield. A wide range of tailorable viscoelastic states was obtained, and allowed the formation of continuous polymer filaments. Understanding the nature and effect of these modifications on the processing state can improve the current state of CMC processing, and open novel processing routes for constituent development.