Method of chemical bonding of solid propellant grains to the internal

Abstract

The trimer of 1,6-hexanediisocyanate, which has the chemical name in acconce with (International Union of Pure and Applied Chemistry) (IUPAC) nomenclature of 7-aza-8-oxo-7[1-isocyanato-6-oxohexyl]pentadecanediisocyanate, is employed in a method of chemical bonding of solid propellant grains to the internal insulation of an interceptor motor. Both the propellant composition and the insulation are chemically reactive with the trimmer identified hereinabove. The method comprises providing a solid propellant rocket motor case having the internal insulation installed therein. Following degreasing of the insulation outer surface, the trimer identified hereinabove is spray coated onto the insulation, and the solid propellant composition is placed onto the trimer. A chemical bond is formed between the propellant and the trimer and the insulation to achieve the chemical bonding of an isocyanate curable solid propellant composition to the internal insulation. The insulation employed in the preferred embodiment is formulated with ethylene-propylene-diene monomer prepolymer, peroxide-cured, and plasticized with 9% dioctyl sebacate. The propellant composition is cast onto the spray coated insulation surface where the chemical insulation-to-polyisocyanate-to-propellant bond is achieved which shows superior tensile, shear, and peel strength when compared to conventional insulation-liner-propellant bonding by prior art.