ABSTRACT Preceramic polymers (PCPs) are versatile ceramic precursors with tunable processing and composition, but their use is limited by shrinkage and mass loss during pyrolysis. PCP‐grafted nanoparticles (PCP GNPs) mitigate these limitations by reducing shrinkage, enhancing char yield, and imparting viscoelasticity for additive manufacturing. Here, we investigate PCP GNPs dispersed in SMP‐10 to establish chemistry‐dependent structure‐dynamics‐processing relationships and contrast them with SMP‐877 systems. Rheology shows SMP‐10 is Newtonian, whereas PCP GNP addition induces shear thinning and network formation. At ∼60 wt%, storage modulus exceeds loss modulus, indicating rheological percolation via grafted polymer networks. X‐ray photon correlation spectroscopy confirms restricted particle mobility with increasing loading and a direct transition from diffusive to ballistic motion. Thermogravimetric analysis reveals synergistic char yield enhancements that peak in the percolated regime (50–70 wt%), demonstrating that network formation suppresses polymer mobility and volatilization during pyrolysis giving rise to a higher char yield of 29.3–33.9 wt% after thermal treatment when compared to SMP‐877, respectively. Additionally, the percolation threshold and char yield increase due to differences in polycarbosilane crosslinking chemistry, compared to SMP‐877. These results establish design rules for PCP GNP‐polycarbosilane systems and identify SMP‐10 as a promising matrix for printable, high‐yield preceramic inks.
Germanton et al. (Wed,) studied this question.