The effect of variation of polyamide hardener (EH411) on a novolac epoxy resin (Dobeckot E4)has been studied in terms of tensile strength and percent elongation. Based on a combination of tensile strength and percent elongation, formulation 9 (Dobeckot E4:100 + hardener EH411:50 )has been selected for studying the effect of liquid polysule de rubbers (LP-32 and LP-33 ). The data indicate that gel time, tensile strength, heat resistance, and e ame retardancedecrease,whereaselongationanddioctyladipateabsorptionincreaseastheproportionofliquidpolysule de rubbers increases. The effect of antimony trioxide and alumina trihydrate e llers on formulation 20 (Dobeckot E4 :100 + hardener EH411 :50 + LP-33:20 ) and formulation 21 (Dobeckot E4:100 + hardener EH411:50 + LP33:30) has also been studied. Based on tensile strength, elongation, dioctyl adipate absorption, heat resistance, and e ame retardance data, formulation 27 (Dobeckot E4 : 100 + hardener EH411:50 + LP-33:30 + Sb 2O3 :40) has been selected for inhibition followed by static evaluation of hydroxy-terminated-polybutadine- (HTPB-)based tubular composite propellants. The pressure ‐time proe les from i 40 to 50±C indicate that the formulation 27 (Dobeckot E4:100 + hardener EH411:50 + LP-33:30 + Sb 2O3 :40) is a viable inhibition system for inhibition of HTPB-based composite propellants.