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Wang X.-B.,Beijing Institute of Technology | Li J.-Q.,Beijing Institute of Technology | Li J.-Q.,Academy of Ordnance Science | Luo Y.-J.,Beijing Institute of Technology
Huozhayao Xuebao/Chinese Journal of Explosives and Propellants | Year: 2012

Ammonium perchlorate/graphene aerogels (AP/GA) nanocomposites were prepared by sol-gel method and characterized by scanning electron microscope(SEM), elemental analysis and X-ray diffraction(XRD). Their thermal decomposition behaviours were investigated by TG-DSC-IR. The results indicate that AP is presented in the AP/GA nanocomposites with an average particle size of 69.41nm and occupied 94.4% of total mass. GA shows an obvious catalytic effect on the thermal decomposition of AP/GA. Compared to pure AP, the low temperature decomposition peak of AP/GA nanocomposites disappears, the high temperature decomposition peak temperature decreases by 83.7°C, and the total heat release reaches 2110 J/g. Source


Wang X.,Beijing Institute of Technology | Li J.,Beijing Institute of Technology | Li J.,Academy of Ordnance Science | Luo Y.,Beijing Institute of Technology
Fuhe Cailiao Xuebao/Acta Materiae Compositae Sinica | Year: 2013

Graphene aerogel (GA) was prepared by sol-gel chemistry, and then GA/epoxy (EP) composites were prepared by sonicate-mixing method. The structure of GA was characterized by SEM, N2 nitrogen sorption tests, XPS and XRD. In addition, the effects of GA mass fraction on the thermal property and the conductivity property of the GA/EP composites were also investigated. The results indicate that the GA shows a three-dimensional network of randomly oriented graphene sheets with wrinkled texture, and is rich in pores. After thermal reduction, the specific surface area of GA increases to 731.84 m2·g-1, the interlayer spacing of the graphene decreases to 0.347 nm, and the oxygen-containing functional groups are almost all removed. DMA and electrical conductivity testing results show that with the increase of GA content, Tg of GA/EP composites increases first and then decreases, and the electrical conductivity increases with the percolation threshold of 0.05%-0.3%. Source


Zhang W.-Y.,Beijing Institute of Technology | Li J.-Q.,Academy of Ordnance Science | Luo Y.-J.,Beijing Institute of Technology | Li X.-M.,Beijing Institute of Technology | Jiu Y.-B.,Beijing Institute of Technology
Hanneng Cailiao/Chinese Journal of Energetic Materials | Year: 2012

A series of thermoplastic polyurethane elastomers(TPUEs) with bonding function which can be used as propellant binders were synthesized from polyethylene/polypropylene adipate diol(PEPA), tetrahydrofuran/ethylene oxide copolyether(PET), isophorone diisocyanate(IPDI), 1, 4-butanediol (BDO) and diethyl bis(hydroxymethyl) malonate(DBM) as primary substances by melt pre-polymerization method. Then Fourier transform infrared spectroscopic(FTIR), gel permeation in chromatography(GPC), differential scanning calorimetry(DSC) and tensile test techniques were employed to characterize the structures and properties of TPUEs. Results show that the microphase segregation of TPUEs become more obvious with the BDO content in chain extenders increasing. When the molar content of BDO exceeds 50% in chain extender, the glass transition temperature of soft segment become lower than -70°C. It is also observed that tensile strength of the TPUE increased with the BDO content increasing, while the elongation to break decreased. TPUEs extended with mixed diols have better effect than that extended with BDO or DBM to improve the mechnical properties of modified double-based propellant. Source


Wang X.,Beijing Institute of Technology | Li J.,Beijing Institute of Technology | Li J.,Academy of Ordnance Science | Luo Y.,Beijing Institute of Technology | Huang M.,Beijing Institute of Technology
Science of Advanced Materials | Year: 2014

A novel ammonium perchlorate (AP)/graphene aerogel (GA) nanostructured energetic composite was prepared by the sol-gel method. The structure was characterized by using scanning electron microscope (SEM), nitrogen sorption tests and X-ray diffraction (XRD). The thermal decomposition behavior was investigated by using thermogravimetric analysis/differential scanning calorimetric/infrared spectrometry (TG-DSC-FTIR). The results show that the as-prepared AP/GA nanostructured energetic composites have numerous nanoscale pores and the specific surface area is 49.18 m2 g-1. The XRD results show that AP homogeneously disperses in the energetic composites at nanometric scale. TG-DSC-FTIR analysis indicates that GAs exhibit high promoting effects in the thermal decomposition process of AP. After incorporating with GAs, the hightemperature decomposition of AP is accelerated and its total heat release is significantly increased which is caused by the oxidation reaction between GAs and the oxidizing products. This study provides a new choice of metastable intermolecular composites which may have great potential in use for the solid rocket propellants. © 2014 by American Scientific Publishers. Source


Zhang W.-Y.,Beijing Institute of Technology | Li J.-Q.,Academy of Ordnance Science | Luo Y.-J.,Beijing Institute of Technology
Huozhayao Xuebao/Chinese Journal of Explosives and Propellants | Year: 2010

A series of novel thermoplastic polyurethane elastomers(TPUE) containing side ester groups which can be used as propeliam binder were synthesized from polyethylene/polypropylene adipate diol ( PEPA ), tetrahydrofuran/ethylene oxide copolyether ( PET ), isophorone diisocyanate ( IPDI ) and diethyl bis (Hydroxymethyl) malonate (DBM) as primary substances by melt pre-polymerization method. FTIR, GPC, DSC and tensile test were employed to characterize the structures and properties of TPUE. Results show that the polyurethane elastomers present higher molecular weight (Mn>8×104), and have relatively lower glass transition temperature of soft segment (T, < -56 C) which indicate that they have good low temperature mechanical properties. The elastomers exhibit optimum mechanical properties (σ >18 MPa and ε>500%) when the hard segment concentration is controlled between 50% and 60%. When the TPUE is introduced into modified double base propellant, the mechanical properties at low temperature are remarkably improved and the tensile strength at high temperature are slightly lowered. Source

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