Yang Q.,Chengdu University of Technology |
Yu H.,Southwest University |
Song L.,Southwest University |
Lei Y.,Institute of Chemical Materials |
And 4 more authors.
Journal of Applied Polymer Science | Year: 2017
A series of microcellular high temperature vulcanized (HTV) silicone rubber foams were prepared using CO2 as a physical blowing agent. Rheological properties, gas diffusive behavior, and foaming parameters of silicone rubber were investigated. The results show that saturation pressure has a significant effect on the diffusivity of CO2 in HTV silicone rubber matrix. The gas concentration and diffusivity increase from 2.45 wt % to 3.24 wt %, and from 1.62 × 10-5 cm2/s to 7.83 × 10-5 cm2/s as the saturation pressure increases from 2 MPa to 5 MPa, respectively. The value of the gas diffusivity in HTV silicone rubber is almost 1000 times higher than that of the gas diffusivity in polyetherimide (PEI) matrix. Additionally, microcellular HTV silicone rubber foams with the smallest cell diameter of 9.8 μm and cell density exceeding 108 cells/cm3 are achieved. © 2017 Wiley Periodicals, Inc.
Han Y.,Institute of Chemical Materials |
Long X.-P.,China Academic of Engineering Physics |
Huang H.-J.,Institute of Chemical Materials |
Nie F.-D.,Institute of Chemical Materials |
Huang Y.-M.,Institute of Chemical Materials
Binggong Xuebao/Acta Armamentarii | Year: 2012
In order to get the detonation front structure of TATB-based PBX explosive, the interface velocity between detonated PBX explosive and PMMA window was measured using all-fiber displacement interferometer (DISAR). The frequency sign in oscillograph was analyzed by the method based on short time Fourier transform and wavelet transform algorithms. The results reveal that there is not obvious inflection point in the history of particle velocity. Thermo-chemical code VLW was used to calculate the iso-entropy curves of detonation products of PBX, and 235 ns reaction time in the reaction zone of PBX was obtained by the impedance matching method.
Li T.,Institute of Fluid Physics |
Hua C.,Institute of Chemical Materials |
Li Q.,Institute of Fluid Physics
Propellants, Explosives, Pyrotechnics | Year: 2013
The shock sensitivities of plastic bonded explosives were studied with a thin flyer impact test by using two types of pressed RDX. The thin flyer, driven by an electrically exploding plasma, exerts a short-duration, high-pressure pulse to the samples to trigger a shock-to-detonation process. It was found that the duration and magnitude of the incident shock strongly influence the dominant mode of hot-spot formation, promoting a fast pore collapsing mechanism while suppressing other slower shear or friction mechanisms, as proposed by Chakravarty et al. . The pressed PBX based on reduced sensitivity RDX had higher shock threshold pressure, compared to the pressed PBX based on commercial RDX. The difference was observed even with a certain portion of external extragranular defects. It is postulated that the internal crystal defects are more efficient than the external porosity in terms of the rapid reaction of hot spots. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Lin H.,Nanjing University of Science and Technology |
Zhu S.-G.,Nanjing University of Science and Technology |
Li H.-Z.,Institute of Chemical Materials |
Peng X.-H.,Nanjing University of Science and Technology
Journal of Physical Organic Chemistry | Year: 2013
Intermolecular interactions and properties of octahydro-1,3,5,7-tetranitro- 1,3,5,7- tetrazocine (HMX) / 2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105) cocrystal were studied by using the dispersion-corrected density functionals (ωB97XD, B97D) and meta-hybrid functional (M062x) methods. Binding energies, heats of formation, thermodynamic properties, atoms in molecules, and natural bond orbital analysis were performed to investigate HMX/LLM-105 complexes. Results show that the main intermolecular interactions between HMX and LLM-105 are CH.O, NH.O, N.O, and O.O interactions. In addition, Monte Carlo simulation was employed to predict the crystal structure of HMX/LLM-105 cocrystal. The HMX/LLM-105 cocrystal is most likely to crystallize in C2/c space group, and its corresponding cell parameters are Z = 8, a = 41.63 Å, b = 6.77 Å, c = 45.63 Å, ß = 164.55°, and ρ = 1.99 g/cm3. Detonation velocity and pressure of HMX/LLM-105 cocrystal are 8.95 km/s, 37.69GPa, a little lower than those of HMX (9.10 km/s, 37.76GPa). However, according to the net charges of nitro group, HMX/LLM-105 cocrystal exhibits less sensitive than HMX. Finally, bond dissociation energy calculation shows that HMX/LLM-105 complexes are thermally stable. Considering thermal stability, sensitivity, and detonation performance, HMX/LLM-105 cocrystal meets the requirements of insensitive high energy density materials. Copyright © 2013 John Wiley & Sons, Ltd.
Liu Y.-G.,Institute of Chemical Materials |
Jiang Y.-Q.,Institute of Chemical Materials |
Liu S.-J.,Institute of Chemical Materials |
Wen Y.-S.,Institute of Chemical Materials |
Zhang J.-H.,Institute of Chemical Materials
Binggong Xuebao/Acta Armamentarii | Year: 2012
The influence of polymer binder on the impact sensitivity and shock sensitivity of pressed PBX was studied by drop weight impact test and gap test. The correlation between the thermal property of binder and the impact sensitivity of PBX was found. The results show that the thermal and mechanical properties of binder have an important influence on impact sensitivity. A polymer binder with high specific heat, high latent heat of fusion and high thermal conductivity has better desensitizing effect. The shock sensitivity could be improved by adjusting the mechanical properties of PBX. The results should be useful for the design of new desensitizing binder and the prediction of impact sensitivity and shock sensitivity of PBXs.
Bai J.-W.,University of Sichuan |
Bai J.-W.,Institute of Chemical Materials |
Zhong F.-C.,Institute of Chemical Materials |
Liu X.-Y.,Institute of Chemical Materials |
Zhang J.-H.,University of Sichuan
Polymer International | Year: 2014
Magnetic TNT imprinted polymers were prepared via a facile approach. Scatchard plot indicates the formation of two kinds of binding sites in the MIPs. A safe and facile approach for the preparation of magnetic molecularly imprinted polymer nanospheres for 2,4,6-trinitrotoluene (TNT) recognition is reported. The imprinted nanospheres were synthesized using TNT as the imprinting molecule, acrylamide as the functional monomer, N,N'-methylenebisacrylamide as the crosslinker and magnetic particles as the support. The structure of the materials was identified via Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and transmission electron microscopy. Static adsorbing experiments were carried out and Scatchard plot analysis showed that two kinds of receptor sites were formed in the imprinted materials. The adsorption equilibrium constant and the maximum adsorption capacity were evaluated. These results indicated that the imprinted nanospheres have higher adsorption capacity and selectivity for TNT than non-imprinted polymer nanospheres with the same composition. © 2013 Society of Chemical Industry.