TABLE OF CONTENTS Four applications are selected as examples for this section: ( a) nanocomposite rocket ablative materials (NRAMs), ( b) flammability properties of polymer nanostructured materials, ( c) nanomodified carbon/carbon composites (NCCCs), and ( d) nanocomposites for carbon fiber-reinforced polymer matrix composites (NCPMCs). These examples were used to illustrate the processing techniques to form the desired polymer nanocomposites and to transform them into polymer nanostructured materials for the intended applications. Flammability properties, mechanical properties, and performance characteristics for their specific applications are included.
Ablative materials are required to protect aerospace propulsion systems against rocket exhaust plumes. The flow environment of solid rocket exhaust is particularly hostile. System components need to be protected from extreme flow temperatures of 1000 to 4000 C and from highly abrasive particles ejecting at velocities greater than 1000 m/s. Phenolic matrix composites have been used extensively for ablative materials. Current rocket nozzle assemblies are made of carbon phenolic composites such as MX-4926 from Cytec Engineered Materials (CEM). Three versions of carbon phenolic ablative MX-4926 laminates were fabricated by CEM as controls for this study. The three versions of MX-4926 laminates were fabricated based on fiber orientation: ( a) 60 shingle, ( b) molding compound, and ( c) two-dimensional fabric.
Vaia et al.39 examined the ablative performance of poly(caprolactam) (nylon 6) nanocomposites. A relatively tough, inorganic char forms during the ablation of these nanocomposites, resulting in at least an order-of-magnitude decrease...
