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The pressure characteristics and safety performance of dihydroxylammonium 5,5ʹ-bistetrazole-1,1ʹ-diolate (TKX-50) decomposition were studied in confined space by using the accelerating rate calorimeter (ARC). The effects of the heating rate and the sample amount on the safety performance were investigated. The experiment results revealed that high heating rate was harmful to the safety performance of TKX-50. The decomposition mechanism did not change when using different amounts of sample in the range between 47.5 and 72.5 mg. After ignition, TKX-50 exhibited better safe performance than RDX and HMX.

Xin Li,1 Xiaoqian Jia,2 Hu Niu2 1Department of Breast and Thyroid Surgery, Heze Municipal Hospital, Heze, Shandong, China; 2Department of General Surgery 2, The Fourth People’s Hospital of Jinan, Jinan, Shandong, China Background: Multidrug resistance is responsible for the poor outcome in breast cancer therapy. Lapa is a novel therapeutic agent that generates ROS through the catalysis of the NAD(P)H:quinone oxidoreductase-1 (NQO1) enzyme which significantly facilitate the intracellular accumulation of the co-delivered DOX to overcome MDR in cancer cells. Purpose: Herein, in our study, nanostructured lipid carrier (NLC) co-delivering β-lapachone (Lapa) and doxorubicin (DOX) was developed (LDNLC) with the aim to overcome the multidrug resistance (MDR) in breast cancer therapy. Patients and methods: Lapa and DOX were loaded into NLC to prepare LDNLC using melted ultrasonic dispersion method. Results: The well designed LDNLC was nanoscaled particles that exhibited preferable stability in physiological environment. In vitro cell experiments on MCF-7 ADR cells showed increased DOX retention as compared to DOX mono-delivery NLC (DNLC). In vivo anti-cancer assays on MCF-7 ADR tumor bearing mice model also revealed significantly enhanced efficacy of LDNLC than mono-delivery NLCs (DNLC and LNLC). Conclusion: LDNLC might be a promising platform for effective breast cancer therapy. Keywords: β-lapachone, doxorubicin, nanostructured lipid carriers, multidrug resistance, breast cancer

Thermal decomposition and safety assessment of 3,3′-dinitrimino-5,5′-bis(1H-1,2,4-triazole) (DNABT) were investigated by thermogravimetry–derivative thermogravimetry–differential scanning calorimetry (TG-DTG-DSC), differential thermal analysis (DTA), and accelerating rate calorimetry (ARC). The result of TG-DTG-DSC at a heating rate of 10 °C min−1 indicated that an endothermic decomposition and an exothermic decomposition occurred at 133.98 and 210.86 °C, respectively. The apparent activation energy (Ea) and pre-exponential factor (A) of the exothermic decomposition, and the free energy of activation, activation enthalpy, and activation entropy at initial decomposition temperature (Tp0) were calculated from the DTA curves recorded at the heating rates of 1, 2, 4, 8 °C min−1. The critical temperature of thermal explosion (Tbp0) obtained by Ozawa’s and Kissinger’s methods were calculated as 205.01 and 205.14 °C, respectively. The result of ARC indicated that the self-heating decomposition started at 200.22 °C and ended at 232.66 °C. The self-heating decomposition parameters, including the onset temperature, final temperature, temperature at maximum rate, maximum temperature rate, adiabatic temperature rise, and time to maximum rate were obtained, and these parameters were corrected by thermal inertia factor. The Ea and A under adiabatic condition were also calculated. In addition, the self-accelerating decomposition temperature (TSADT, 50kg) was calculated as 175.37 °C. These results could contribute to improve the safety in the reaction, transportation, and storage processes of DNABT.

Several polymer binders based on 3,3-bis(azidomethyl)oxetane (BAMO) were studied to explore the compatibility and interaction of the energetic binders with three common energetic oxidants. The compatibilities were studied by differential scanning calorimetry (DSC) and the rating was obtained according to the evaluated standards. The results showed that all the binders based on BAMO had a good compatibility with cyclotrimethylenetrinitramine (RDX), cyclotetramethylenetetranitroamine (HMX), and hexanitrohexazaiso- wurtzitane (CL-20). The work of adhesion (Wa) between binders and explosives was tested via measurement of contact angle and the results present the same orders: chain-extended PBAMO by isophorone diisocyanate with diethyl bis(hydroxymethyl) malonate (IPDI-DBM-CE) > chain- extended PBAMO by isophorone diisocyanate (IPDI-CE) > poly(3,3-bis(azidomethyl)oxetane) (PBAMO). In addition, similar results were found in the binding energies reported by the molecular dynamics (MD), and the average values of Ebinding for IPDI-DBM-CE systems were larger than others due to the formation of hydrogen bonds between –COOEt and –NO2, which would improve the bonding abilities.

TKX-50-based PBX (PBX-T) is prepared by solution–water suspension method using dihydroxylammonium 5,5′-bistetrazole-1,1′-diolate (TKX-50) as the explosive. The thermal behavior of PBX-T is investigated under a nonisothermal condition by using TG-DTG and DSC method. The kinetic parameters (E a = 167.98 kJ mol−1 and A = 1016.05 s−1) for the main thermal decomposition reaction of PBX-T are calculated from the analysis of DSC curves by differential method and integral method, and the nonisothermal kinetic equation of the exothermic process is $${\text{d}}\alpha /{\text{d}}T = \left( {10^{16.05} /2\beta } \right)5\left( {1 - \alpha } \right)\left[ { - \ln \left( {1 - \alpha } \right)} \right]^{3/5} \exp ( - 2.0204 \times 10^{4} /T)$$ , suggesting that the main exothermic decomposition reaction mechanism of PBX-T is classified as Avrami–Erofeev equation. The specific heat capacity (C p) of PBX-T is measured using continuous C p mode of C80 micro-calorimeter. Depending on the thermal decomposition parameters and Chinese Military Standards GJB 772A-97 method, the adiabatic time, self-accelerating decomposition temperature, sensitivities, and 5-second flash point on of PBX-T are obtained.

The enthalpies of dissolution for dihydroxylammonium 5, 5′-bistetrazole-1,1′-diolate (TKX-50) in water were measured using a C-80 Calvet microcalorimeter at four different temperatures under atmospheric pressure. Differential enthalpies (Δdif H) and molar enthalpies (Δdiss H) of dissolution were calculated. The corresponding kinetic equations that describe the dissolution rate at the four experimental temperatures are dα/dt = 10−3.06(1 − α)0.59 (T = 298.15 K), dα/dt = 10−2.98(1 − α)0.37 (T = 303.15 K), dα/dt = 10−2.90(1 − α)0.37 (T = 308.15 K), dα/dt = 10−2.85(1 − α)0.43 (T = 313.15 K). In addition, the determined values of the activation energy E and pre-exponential factor A for the dissolution process are 25.08 kJ mol−1 and 21.98 s−1, respectively.

The enthalpies of dissolution for 5,5′-Bistetrazole-1, 1′-dihydroxy ((H2O)2BTO) and disodium 5,5′-Bistetrazole-1,1′-diolate ([Na2(H2O)4]BTO) in dimethyl sulfoxide (DMSO) at 298.15 K were studied by using a C-80 Calvet microcalorimeter. Empirical formulae for the calculation of the molar enthalpies of dissolution (Δdiss H), relative partial molar enthalpies (Δdiss H partial), and relative apparent molar enthalpies (Δdiss H apparent) were deduced by the experimental results of the dissolution processes of (H2O)2BTO and [Na2(H2O)4]BTO in DMSO. Finally, the corresponding kinetic equations describing the dissolution processes were dα/dt = 10−2.60(1−α)0.61 for the dissolution of (H2O)2BTO in DMSO, and dα/dt = 10−2.69(1−α)0.62 for the dissolution of [Na2(H2O)4]BTO in DMSO.

Electric coalescence is an effective way to achieve high performance of separating small dispersed water droplets from oils. We investigated the coalescence and break-up behaviors of double conducting droplets dissolved 0.4394 M NaCl in the presence of electric field using molecular dynamic simulations. Our results provide that the critical electric field (Ec) and the corresponding conical angle for coalescence are 0.52 V/nm and 42°. Two conducting droplets are driven to approach, contact, and eventually coalescence by the electric field when the applied electric field is weaker than Ec. Nevertheless, in the presence of the electric field stronger than Ec, the partial break-up that small daughter droplets break away from their mother droplet occurs due to the exchange and neutralization of positive and negative charged ions in the connecting liquid bridge. As the electric field increases further to 0.80 V/nm or stay above, the strong electric field leads to the entire break-up process, accompanied with ion jetting before droplets contacting.

Dihydroxylammonium 5,5′- bistetrazole-1,1′-diolate (TKX-50) was used to prepare TKX-50-based polymer bonded explosive (PBX) for the first time in this study. The thermal stabilities and the kinetic parameters of TKX-50 and TKX-50-based PBX were compared via Differential Scanning Calorimetry (DSC), Thermal Gravity-Differential Thermal Gravity (TG-DTG) and Accelerating Rate Calorimeter (ARC). Furthermore, in order to know about their thermal safeties comprehensively, an advanced thermal analysis program based on Friedman method was employed to calculate the thermal safety parameters for TKX-50 and its PBX. With its help, two important safety parameters (time to maximum rate under adiabatic conditions (TMRad) and self-accelerating decomposition temperature (SADT)) for the two energetic materials were calculated and discussed. Finally, based on the safety parameters, effects of storage conditions and ambient temperatures on the thermal explosions of TKX-50 and TKX-50-based PBX were further studied by using finite element analysis (FEA).

A derivative of squaramide (cyclobuta[b]quinoxaline-1, 2(3H, 8H)-dione) has been synthesized for the ratiometric and colorimetric sensing of F(-) in aqueous solution in competitive fashion. With F(-), probe 1 showed a highly selective naked-eye detectable color change along with a characteristic UV-Vis absorbance over other tested ions, which probably originates from the deprotonation occurred between 1 and F(-), as proved by the (1)H NMR titration experiments and DFT calculations.