Polymer Nanocomposites as Ablative Materials - A Comprehensive Review(Abstract)

摘要

One of the most important and pioneering research on the use of the montmorillonite (MMT) organoclay as ablative material was investigated by Vaia et al. of Air Force Research Laboratory (AFRL) in 1999 [1]. The authors compared the ablative behavior of neat poly (caprolactam) (nylon 6) to a 2 wt% and 5 wt% loaded layered silicate/poly(caprolactam) nanocomposite. These polymer nancocomposites (PNCs) were synthesized by in situ polymerization of e-caprolactam in the presence of dispersed organically modified MMT organoclay. The ablation rate of these PNCs was determined from exposure to combustion gases produced by a subscale solid rocket motor. Experimental results showed that the mesoscopic structure of the exfoliated PNCs resulted in a substantial improvement of ablative performance relative to the neat polymer. A relatively tough, inorganic char formed during the ablation of the poly(caprolactam) nanocomposites. This refractory char resulted in at least an order of magnitude decrease in the mass loss rate relative to the neat polymer, even for as little as 2 wt% (approx 0.8 vol%) exfoliated layered silicate.