Properties and application of a novel type of Glycidyl Azide Polymer (GAP)-modified nitrocellulose powders

GAP-modified nitrocellulose powders were prepared by an internal solution method and applied in cross-linked modified double base (XLDB) propellants. It was found that GAP-modified nitrocellulose powders exhibit high round, no bonding between the particles and excellent fluidity. When the amount of GAP increased from 10.0% to 30.0%, the median diameter (d₅₀) of powders decreased from 134.53 μm to 94.54 μm. The thermal decomposition process of GAP appeared also in the GAP-modified nitrocellulose powders, but the thermal decomposition peak temperatures of -N₃ and the GAP main chain were found to be lower for the 10.0% and 20.0% GAP-modified samples than the corresponding peak temperatures for pure GAP, respectively. The plasticizing properties of GAP-modified nitrocellulose powders are better than that of pure nitrocellulose powders, and the drop weight impact sensitivity of the modified powders is reduced as the mass ratio of GAP increases. It was experimentally shown that GAP-modified nitrocellulose powders can improve the mechanical characteristics of the propellant with a maximum tensile strength (σ_m) between 0.36 MPa < σ_m < 1.10 MPa and an elongation at maximum tensile strength (ε_m) between 28.8% < ε_m < 51.8% at temperatures of -40, +20 and +50°C.