Cyanate ester (CE) is an important class of materials among high-temperature performance thermosets due to their high glass transition temperatures (&gt;220°C), excellent thermal stability, and low flammability. In this work, we demonstrate carborane-filled CE nanocomposites that have an exceptionally high oxidative thermal stability as compared to the pristine resin. Carborane fillers were solvent blended at various mass loadings in the resin and cured to study their effect on thermal properties. Our TGA experiments show that the ultimate char yield of the resin can be increased from 0% to as high as 76 and 82.1% with 30 wt.% PD and EP carborane loading respectively at 1000 deg C in air. We interrogated the degradation mechanism of these carborane-CE composites through FTIR, Elemental Analysis, TGA-Mass Spectroscopy (TGA-MS), and solid-state 11B and 12C NMR. We have discovered that the iminocarbonate and oxazolidinone linkages between CE and carboranes are labile, producing a moderate temperature (ca. 450 deg C) initial degradation in TGA. Howbeit, at higher temperatures (&gt; 650 deg C) the carborane structure disintegrates and is oxidized to boronic acid and boroxine structures.<br/>In further studies, we are now working to translate these mechanistic insights to design other thermally protected thermoset matrices such as epoxies. Additionally, we are elucidating the effect of boron-based fillers on mechanical properties.

High-temperature performance cyanate ester composites with carboranes

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.