Preceramic polymer-grafted nanoparticles assembled via ionic complexation

Abstract

High-temperature, structural ceramics are critical for demanding aerospace applications. Ceramic precursors or preceramic polymers (PCPs) may be utilized for ceramic production. Recent advances in chemistry provide an opportunity to improve PCP synthesis and design. Herein, we leverage ionic interactions to create PCP grafted-nanoparticles, inspired by prior work on nanoscale ionic materials (NIMs). Linear and hyperbranched cationic polycarbosilanes were synthesized for NIMs assembly. PCP NIMs were created by assembling these cationic PCPs with silica nanoparticles that had been surface-modified with sulfonate groups. The resulting PCP NIMs were characterized with respect to morphology, rheology, thermal stability, thermal processing, and ceramic formation. Hybrid materials prepared with linear PCPs did not yield appreciable polymer-derived ceramic after firing, while those utilizing a modified, hyperbranched commercial PCP produced a SiC/SiO2 composite material. These results represent a compelling proof-of-principal study that establishes the feasibility of using a dynamic ionic bonding strategy to assemble PCP-based hybrid nanomaterials.

Keywords

• Nanoscale ionic materials
• Preceramic polymers
• Polycarbosilanes
• Pyrolysis
• Polymer-grafted nanoparticles
• Silicon carbide