New ablative composite materials based on mesoporous silica nanoparticles

LUCÍA ASARO; MARIELA COLOMBO; SERGIO PELLICE; RAÚL PROCACCINI; LILIANA MANFREDI; EXEQUIEL RODRÍGUEZ

Buenos Aires

Conferencia; 6th International Conference on Science and Technology of Composite Materials; 2015

UBA - Facultad de Ingeniería

In this work, mesoporous silica nanoparticles were synthesized and added to phenolic resin/carbon fiber composites in order to obtain ablative resistance materials. These composites are used in aerospace application were very high temperature resistance is required (e.g. nozzle of rocket engines). Mesoporous nanoparticles were obtained by sol-gel and the mesoporosity was confirmed by transmission electronic microscopy (TEM). Composite material rectangular samples were prepared by compression molding and tested in terms of ablation resistance with an oxyacetylene torch, following the ASTM E285 standard. Unreinforced phenolic resin/nanoparticles composites were first prepared and tested in order to evaluate the effect of the particles on the matrix thermal resistance. During the ablation test, the temperature of the back face of the plaque and the burn-through time were recorded. An insulation index and the erosion rate were then calculated with those values. A carbonaceous residue (char) is formed during the combustion and plays a key role in the ablation resistance, since it acts as an insulation barrier. Silica nanoparticles can stabilize that char, that otherwise is easily removed by the effect of the flame erosion. The results obtained for the silica/phenolic resin materials were compared with the standard materials used in the aerospace industry (phenolic resin + carbon black). The mesoporous structure and the thermal resistance of the silica particles produced an increase in the ablative resistance of the phenolic matrix composites when comparing with the loaded with carbon black. The better performance was also obtained in the final composite materials, reinforced with carbon fibers.