Impact of the Backbone Structure on the Rheological and Thermal Properties of Preceramic Polymer-Grafted Nanoparticles and Derived Ceramics

• Published in: ACS applied nano materials 2022-01, Vol.5 (1), p.446-454
• Main Authors: Martin, Kara L, Street, Dayton P, Thompson, Christina M, Parvulescu, Maria J. S, Dickerson, Matthew B
• Format: Article
• Language: English
• ISSN: 2574-0970; 2574-0970
• DOI: 10.1021/acsanm.1c03278

Here, we demonstrate the synthesis of two novel preceramic grafted nanoparticles (GNPs) and compare their physical properties and derived ceramics to previously reported GNPs. Three variations of preceramic polymer GNPs are synthesized using hydrosilylation grafting-from chemistry, with brushes comprising poly­(1,1-dimethylpropylsilane) (allyl-GNP), poly­(1,1-dimethylethylbenzylsilane) (styryl-GNP), and poly­(1,1-dimethylethylsilane) (vinyl-GNP) on silica nanoparticles (10–15 nm in diameter). The brush structure is confirmed using FTIR, 1H NMR, and dynamic light scattering (DLS). The rheological properties of the GNPs change depending on the brush composition, with the allyl-GNP displaying the formation of a strong interparticle network and the styryl-GNP exhibiting a weaker interparticle network. Thermal gravimetric analysis shows that after thermal treatment, the ceramic yield of all three GNPs increases at 800 °C, with the allyl-GNP and vinyl-GNP showing a significant improvement in yield as compared to the styryl-GNP. Finally, the three GNPs are pyrolyzed to 1400 °C giving ceramic composites with compositions dependent upon the precursor brush, as determined through X-ray diffraction (XRD) and Raman spectroscopy. This study demonstrates that hydrosilylation grafting-from is a robust method of anchoring ceramic precursor polymers to nanoparticles and can be employed to produce preceramic GNPs that subsequently convert to brush-dependent ceramic composites.