New Thermo-Oxidative Protective Coating for Carbon/ Carbon Composites in Mid-Temperature Range Using a Combination of Nano-Filler and Macro-Filler With Polybenzoxazine as a Carbon-Forming Matrix

摘要

A novel main-chain type, oligomeric benzoxazine has been synthesized as a highly thermo-oxidative matrix material. The structure of the monomer is confirmed by ~1H nuclear magnetic resonance spectroscopy and size exclusion chromatography. Octasilane polyhedral oligomeric silsesquioxane (OctaSilane POSS) and glass sphere are incorporated to form an effective oxidation-protective coating for the carbon/carbon composites. The composition has been optimized by varying benzoxazine and OctaSilane POSS ratio with the aid of thermogravimetric analyses. The even distribution of the three components has been confirmed by laser Raman image, and the effectiveness of the coating has been investigated using isothermal weight loss measurement at 700℃ in air for 1300 h.