Preparation and Characterization of Polyurethane/Nitrocellulose Blends as Binder for Composite Solid Propellants

Abstract Polyurethane (PU) elastomers are largely used in the field of high‐energy composites such as composite solid propellants (CSPs) and high‐energy polymer‐bonded explosives (PBXs) due to their distinguished characteristics. Conventional PU binders are mostly non‐energetic materials, and consequently reduce the energy performance significantly. Nitrocellulose (NC), is an energetic polymer widely used as an ingredient in propellants, explosives, fireworks, and gas generators, may be introduced in PU‐based compositions to overcome their performance drawback. In this context, PU/NC polymer blends at different mass ratios were prepared in the present work using hydroxyl‐terminated polyester prepolymer (Desmophen® 1200) and nitrocellulose (NC) by solution blending process. The physico‐chemical structure of the prepared PU/NC polymer composites were characterized by Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD) and density measurements. The thermal decomposition behavior was investigated by differential scanning calorimetry (DSC). Based on the obtained DSC results, the Arrhenius parameters were computed by different isoconversional kinetic approaches, namely, iterative Kissinger‐Akahira‐Sunose (It‐KAS), iterative Flynn‐Wall‐Ozawa (It‐FWO) and Vyazovkin's nonlinear integral method coupled with compensation effect (VYA/CE). Additionally, in order to highlight the influence of the introduction of the NC to the binder composition on the performance of a composite propellant, the theoretical performances, namely, theoretical specific impulse, the adiabatic flame temperature, as well as the ideal exhaust gaseous species were determined based on NASA Lewis Code, Chemical Equilibrium with Application (CEA).