Thermal insulation behaviour of Ethylene propylene diene monomer rubber/kevlar fiber based hybrid composites containing Nanosilica for solid rocket motor insulation

The current research discusses the properties of an elastomeric heat-shielding material, based on nano-silica (NS) filled ethylene propylene diene monomer (EPDM) rubber/Kevlar fiber (KF) hybrid composites. The developed elastomeric insulating material consists of an aromatic polyamide fiber (KF) and silica nanoparticles. An in-depth analysis of mechanical properties, density, coefficient of thermal expansion, thermal conductivity, thermogravimetric analysis, and heat release rate of the insulating materials -was performed. TEM micrograph represents an excellent distribution of nanoparticles in the EPDM matrix. The improvement in the mechanical and the flame retardancy of the NS filled EPDM/KF hybrid composite insulations is based on the fiber/matrix adhesion. Maleic anhydride grafting confers polarity to the nonpolar rubber matrix. The char residues of the insulations inspected by scanning electron microscopy and energy dispersive spectroscopy are depicting a rigid and rough surface by the optimal composites, which can aid in better insulation. The optimal formulation of the hybrid composites exhibited a 220% enhancement in char residue with improved thermal stability and mechanical properties.