Synthesis and characterization of thermooxidatively stable poly(dimethylsilyleneethynylenephenyleneethynylene) with o-carborane units

Carborane-containing poly(dimethylsilyleneethynylenephenyleneethynylene) (CB-PSEPE) with o-carborane in main chains was prepared by a coupling reaction between poly(dimethylsilyleneethynylenephenyleneethynylene) (PSEPE) and decaborane (B10H14) in the presence of acetonitrile (CH3CN). The chemical structures of CB-PSEPE were determined by infrared (IR) and nuclear magnetic resonance (NMR) spectroscopies. The glass transition temperature (Tg) and thermal curing behavior of CB-PSEPE were evaluated with differential scanning calorimetry (DSC). The thermal and thermooxidative stabilities were examined by thermogravimetric analysis (TGA). The results show that CB-PSEPE polymer could be converted into a thermoset below 250 °C. The thermoset exhibits excellent heat resistance especially under air atmosphere. The residue yield at 800 °C arrives at 95.8% for CB-PSEPE thermoset in air. When the thermoset was oxidized at 800 °C for 1 h in air, a protective layer would be formed on the surface of the oxidized product according to scanning electron microscopy (SEM) observations.