Application of nitramines coated with nitrocellulose in minimum signature isocyanate-cured propellants

Cyclotrimethylenetrinitramine (RDX) coated with nitrocellulose (NC-RDX) is prepared by an internal solution method and applied in a minimum signature isocyanate-cured propellant. It was found that RDX was coated or bonded by NC to form NC-RDX particles: the median particle diameter (d(50)) and specific surface area of NC-RDX are in the range from 150 to 240 mu m and 0.03 to 0.04 m(2) . g (1), respectively. The NC-RDX particles could swell in nitrate ester plasticizers with relatively low swelling rate compared with NC added directly in the plasticizers. Different types of ballistic modifiers can be effectively added to NC-RDX. It was experimentally shown that NC-RDX can increase the content of NC in the propellant with viscosities in the range from 371 to 394 Pa s and improve the mechanical characteristics of the propellant with maximum tensile strength (sigma(m)) between 0.48 MPa < sigma(m) < 1.92 MPa, elongation at maximum tensile strength (epsilon(m)) between 28.0% < epsilon(m) < 37.3%, and elastic modulus between 3.18 MPa < E < 8.68 MPa in the temperature range from -40 to 50 degrees C.