Elastomeric ablative nanocomposites used in hyperthermal environments

Pristine multiwalled carbon nanotubes (MWCNTs) along with the silane coupling agent were incorporated into ethylene propylene diene monomer (EPDM) rubber using dispersion kneader and two roller mixing mill to fabricate ablative nanocomposites used in hyperthermal environment encountered by space vehicle or rocket motor. The 1 wt% addition of MWCNTS in the rubber matrix has remarkably reduced the backface temperature elevation up to 40°C during the ablation testing of the ablatives. The linear and mass ablation resistances have been diminished up to 125% and 74%, respectively, while insulation indexes at 110°C backface temperature of the composite specimens have been elevated up to 51% with increasing the MWCNTS incorporation into the EPDM matrix. Thermal stability and heat absorbance capability of the polymer composites were progressed with increasing the filler to matrix ratio. Thermal conductivity/impedance of the ablatives have been conducted according to the ASTM E1225-99 and D5470-03, respectively to execute the effect of MWCNTs concentration on the thermal transport characteristics of the tested specimens. Tensile strength of the composite specimen was augmented up to 42% with increasing nanotubes to polymer ratio. Evenly dispersed MWCNTs in the polymer matrix, polymer pyrolysis, and voids formation in the ablated samples can be scrutinized in the scanning electron microscopy images. POLYM. ENG. SCI., 54:255–263, 2014. © 2013 Society of Plastics Engineers