Poly(phenylene-carborane) for boron-carbide/carbon ceramic precursor synthesized via nickel catalysis

• A poly(phenylene-carborane) (PPB) was synthesized via Ni(0)-catalyzed polymerization.
• PPB exhibited excellent thermal and thermo-oxidative stability.
• PPB has proven to be excellent precursors to boron-carbide/carbon ceramic materials.
• The ceramics showed excellent thermo-oxidative stability.

High thermally and thermo-oxidatively stable poly(phenylene-carborane) (PPB) was synthesized via Ni(0)-catalyzed polymerization of bis(aryl chloride) monomer containing carborane. This polymer was soluble in THF and NMP at room temperature, thus allowing molecular weight and spectroscopic analysis. Number-average molecular weight determined by 1H-NMR spectroscopy was 5.4 × 103 g/mol. The crystalline character of PPB was verified by XRD analysis. This polymer exhibited excellent thermal and thermo-oxidative stability with 5% weight loss temperature to be 707 °C and >1000 °C in nitrogen and air, respectively. High char yields of 93.2% and 97.9% were obtained at 1000 °C in nitrogen and air, respectively. Additionally, PPB has proven to be excellent sing-source precursor to boron-carbide/carbon ceramic materials with high ceramic yields in the range of 91.1%–92.6%. According to XRD analysis, boron carbide crystallization for PPB occurred between 1000 and 1200 °C.

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