Interpenetrating three-dimensional carbon nanotube nanocage network for exceptional thermal and structural stability in polymer composites

초록

Lightweight polymer composites are attractive for weight-sensitive structural applications; however, their low glass transition temperatures (T-g) often lead to mechanical and dimensional instability at elevated temperature, primarily due to the inherent mobility of polymer chains. Increasing the T(g)toward the decomposition temperature is widely accepted strategy to enhance thermomechanical stability. However, increasing chemical crosslink density alone often proves insufficient to suppress segmental motion of polymer under such conditions, especially beyond T-g. Here, we embed rigid threedimensional nanotube nanocages into a polymer network, yielding an interpenetrated architecture that physically restricts polymer chain mobility by acting as nanoscale structural barriers. This architecture increases the T(g)of the resulting nano-composite to 350 degrees C, compared to 160 degrees C for the neat polymer (similar to 119% increase). It also results in a low coefficient of thermal expansion (approximate to 10 ppm degrees C-1 at 300 degrees C) and excellent flame retardancy (similar to 98% reduction in peak heat release rate). By integrating nanocages with carbon-fiber fabric, the hybrid laminates maintain > 90% modulus retention up to 370 degrees C, exceeding practical titanium alloys, demonstrating remarkable potential for high-temperature aerospace applications.

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