In the present study, the viscoelastic response of three composite solid propellants based on hydroxyl-terminated poly(butadiene), ammonium perchlorate and aluminum has been investigated. The investigation was surveyed by dynamic mechanical analysis over a wide range of temperatures and frequencies. The mechanical properties of these materials are related to the macromolecular structure of the binder as well as to the content and nature of solid fillers. The storage modulus, loss modulus, loss factor and glass transition temperature for each propellant sample have been evaluated. The master curves of storage (log G' vs log ?) and loss modulus (log G'' vs log ?) were generated for each propellant. A comparison of logaT vs temperature curves for all propellants indicate conformance to Williams-Landel-Ferry equation. Choosing the glass transition as the reference temperature, WLF equation constants are determined. Fractional free volume at the glass transition temperature and thermal coefficient of free volume expansion values are in accordance with the consideration that Al is reinforcing filler.

The study aim is to develop hybrid filament-wound polymeric composites based on flame retardant polyester resin (UPe) and multi-layer structured glass or combined carbon and glass fibers for use as ablative thermal insulation of rocket motor by wet filament winding technique. The composites have a multi-layered structure consisting of two layers of carbon (CF) or glass woven fabric (GF) and one layer of carbon or glass direct roving (CR or GR, respectively), repeated in three cycles. Structural analysis, performed using FTIR spectroscopy and dynamical-mechanical analysis, confirm highly polymerized network. Lower values of the tanδ peak height indicate improved interfacial adhesion between carbon/glass fibers and UPe. The improvements of thermal insulation index of 37% and erosion rate of 38.6% at 180°C are achieved for combined carbon/glass fiber–based composite compared to the neat UPe. Tensile and interlaminar shear properties are investigated according to the fiber orientation and the highest values of tensile and interlaminar shear strengths are obtained for composites with longitudinal orientation, 417.48 MPa and 22.30 MPa, respectively. Compared to the neat UPe, which degrades after 50 s at 3000°C, the composites are stable up to 192 s.

In design of aircraft it is important to use lightweight , but mechanically strong materials and for this purpose, many new composite structures have been developed, mostly based on strong fibers and a binding resin. In this research a possibility is considered to reinforce composite based on carbon fibers and epoxy resin, adding a small amount of poly (vinyl butyral), PVB and nanostructures of tungsten disulfide. Two kinds of nanoparticles were used in experiments, both known by their good mechanical resistance: fullerene-like nanoparticles and multi-wall nanotubes, IF-WS2 and INT-WS2. Composite samples were prepared to consist of multi-layers of carbon fibers impregnated with epoxy resin and PVB solution containing dispersed nanostructures of WS2 in defined concentrations. Nanoparticles have been observed with scanning electron microscope, SEM. Mechanical properties of the multi-layer composite samples have been tested with two configurations of fiber directions. Analysis has been made to compare results and give conclusions that encourage the future application of these nanostructures to enhance the performance of composites for military aircrafts.