To evaluate the thermal safety of 2,2,2-trinitroethyl-N-nitromethyl amine (TNMA), basic data, including specific heat capacity (C_p) and thermal conductivity (λ), were estimated using empirical formulae. The standard enthalpy of formation of TNMA, Δ_fH_m^θ(TNMA, s, 298.15 K), was calculated by an additive method of contributing bond energy to heat of formation Q_f, and the standard combustion enthalpy Δ_cH_m^θ(TNMA, s, 298.15 K) and standard combustion energy ΔU_m^θ (TNMA, s, 298.15 K) and standard combustion energy ΔU_m^θ (TNMA, s, 298.15 K) were calculated by thermodynamic formulae. The detonation velocity, detonation pressure, and heat of detonation were estimated using the Kamlet-Jacobs equation. The heat of decomposition reaction (Q_d) of TNMA was estimated by an empirical formula, and the thermal behavior of TNMA was studied by differential scanning calorimetry (DSC). The kinetic parameters of the exothermic decomposition reaction of TNMA were obtained from analysis of DSC curves and standard volume of gas evolved (VH) vs time (t) curves determined using a highly sensitive Bourdon glass membrane manometer. The parameters used to evaluate the thermal safety of TNMA, such as the self-accelerating decomposition temperature (T_SADT), critical temperature of thermal explosion (T_be and T_bp), adiabatic time-to-explosion (t_TIad), 50% drop height (H₅₀) of impact sensitivity, critical temperature of hot-spot initiation (T_cr), thermal sensitivity probability density function S(T) for infinite plate-like, infinite cylindrical and spheroidal TNMAwith half-thickness and radius of 1 m at 300 K, peak temperature corresponding to the maximum value of the S(T) vs T curve (T_S(T)max), safety degree (SD), critical thermal explosion ambient temperature (T_acr), and thermal explosion probability (P_TE), were obtained by the above-mentioned basic data. Results show that (1) TNMA has better thermal safety and heat-resistent ability; but in comparison with cyclotrimethylenetrinitramine (RDX), the transition from thermal decomposition to thermal explosion of TNMA is easy to take place. (2) The thermal safety of large scale TNMA with different shape decreases in the order: sphere>infinite cylinder>infinite plate. (3) TNMA has high standard combustion energy and high chemical energy (heat) of detonation, and explosion performance level approaching that of HMX. It is sensitive to shock, has impact sensitivity level approaching those of pentaerythritol tetranitrate (PETN) and tetryl and can be used as a main ingredient of composite explosive.

Graphene hydrogels were prepared by the sol-gel method, and then used to prepare ammonium perchlorate (AP)/graphene composites by the incorporation of AP. The composites were dried naturally in air, freeze-dried, or dried with supercritical CO₂. Scanning electron microscopy (SEM), elemental analyses (EA), and X-ray diffraction (XRD) were used to characterize the structure of the AP/graphene composites dried using different methods. Furthermore, the thermal decomposition behavior of the AP/graphene composites was investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis/infrared spectroscopy (TG-FTIR). Drying method had an obvious influence on the morphology of the AP/graphene composites; only the AP/graphene composites dried with supercritical CO₂ showed similar three-dimensional networks and porous structure to graphene aerogels. Elemental analyses revealed that the AP contents in the AP/graphene composites prepared by drying naturally, freeze-drying, and supercritical CO₂ drying were 89.97%, 92.41%, and 94.40%, respectively. XRD results showed that AP was dispersed homogeneously on the nanoscale in the AP/graphene composites dried with supercritical CO₂ and the average particle diameter of AP was about 69 nm. DSC and TG-FTIR analyses indicated that graphene could promote the thermal decomposition of AP, particularly for the sample dried with supercritical CO₂. Independent of drying method, the low-temperature decomposition of the as-prepared AP/graphene composites was not observed and the high-temperature decomposition was accelerated. Compared to the other two drying methods, graphene in the AP/graphene composites dried with supercritical CO₂ showed most obvious promoting effects. The high-temperature decomposition temperature of the AP/graphene composites dried with supercritical CO₂ decreased by 83.7 ℃ compared with that of pure AP, and the total heat release reached 2110 J·g^-1. Moreover, graphene also took part in the oxidation reactions with oxidizing products, which was confirmed by the generation of CO₂.

The composite double base (DB)/hexogen (RDX)-modified double base (CMDB) propellants (Nos. DB001 and CMDB100) were prepared with the lead complex of 3,6-bis(1H-1,2,3,4-tetrazol-5-ylamino)-1,2,4,5-tetrazine (LCBTATz), with and without the ballistic modifier. Their thermal behaviors and nonisothermal decomposition reaction kinetics were investigated by thermogravimetry, derivative thermogravimetry (TG-DTG), and differential scanning calorimetry (DSC). For the LCBTATz-DB propellant, there was one mass loss stage in the TG curve and one exothermic peak in the DSC curve over the temperature range 350-540 K. For LCBTATz-CMDB, there were two continuous exothermic stages in the TG curve, and only one corresponding exothermic peak in the DSC curve over the range 390-540 K. The exothermal decomposition reaction mechanisms of LCBTATz-DB and LCBTATz-CMDB follow the functions f(α)=α^-1/2 and f(α)=2(1-α)^3/2, respectively (α: conversion degree). The self-accelerating decomposition temperatures (T_SADT), thermal ignition temperatures (T_TITT), critical temperatures of thermal explosion (T_b), adiabatic timesto-explosion (t_Tlad), and thermodynamic parameters of activation reaction were calculated, and the thermal safety was evaluated. For DB001, T_SADT=444.50 K, T_TITT=453.96 K, T_b=471.84 K; t_Tlad=39.36 s. For CMDB100, T_SADT=442.38 K, T_TITT=452.89 K,T_b=464.13 K,t_Tlad=21.3 s. As a high-efficiency combustion catalyst, LCBTATz in double-base propellants increases the propulsion rate and reduces the pressure index for larger scale pressures. This makes the DB propellant appear to have a significant super burning effect at 2-8 MPa and a "mesa effect" at 8-12 MPa. Meanwhile, the pressure exponent of the CMDB propellant decreased to 0.18.

2,2-Azobisisobutyronitrile (AIBN) is a typical material that shows overlap between endothermic phase change and exothermic decomposition. This phenomenon went against the kinetics of AIBN. To properly analyze the effect of endothermic phase change on the exothermic decomposition process and determine the non-isothermal behavior of AIBN in a solvent, a solution of AIBN (22.18% mass fraction) in aniline was tested under dynamic conditions by differential scanning calorimeter (DSC). Depending on heating rates, the onset temperature range of AIBN in aniline was from 79.90 to 94.47 ℃, and the decomposition enthalpy was 291 J·g^-1 greater than that in its pure state, which could be regarded as phase change enthalpy. Based on the Kissinger method, the differences of the activation energy E and the frequency factor A of AIBN and its solution were quite small. The thermal decomposition processes of AIBN and its solution were analyzed by the Friedman method, which showed that the reaction progress range was less than 0.20, in which the endothermic phase change of solid AIBN would disturb its exothermic decomposition. When α was greater than 0.20, the dependence of E(α) and ln(A(α)·f(α)) on α were roughly the same. These results show that aniline is an inertial solvent; that is, decomposition of AIBN is not disturbed by aniline. This means that the decomposition mechanism of AIBN in aniline could be regarded as the same as that in its solid state. The decomposition kinetics of AIBN could be described according to the Mampel power law, G(α)=α^3/2, which is based on the Friedman and Coats-Redfern integral methods, and the average apparent activation energy was 139.93 kJ·mol^-1.

The thermokinetics of the formation reactions of metal (Li, Na, Pb, Cu) salts of 3-nitro-1,2,4-triazol- 5-one (NTO) was studied using a microcalorimeter. On the basis of experimental and calculated results, three thermodynamic parameters (activation energy, pre-exponential constant, and reaction order), rate constant, three thermokinetic parameters (activation enthalpy, activation entropy, and activation free energy) and the enthalpies of the reactions to prepare the metal salts of NTO in the temperature range of 25-40℃ were obtained. The title reactions occur easily in the studied temperature range. Based on Hess' law, the values of Δ_fH_m⁰ (Li(NTO)·2H₂O, aq, 298.15 K) and Δ_fH_m⁰ (Na(NTO)·2H₂O, aq, 298.15 K) are obtained.

In this study, the conductivity of 13 ionic liquids (ILs) and 25 related binary mixtures were determined at temperatures ranging from 293.15-323.15 K. The conductivity data of the pure ILs and their mixtures were fitted using the Vogel-Tammann-Fulcher (VTF) equation. The ionic association in the ILs and IL mixtures was discussed using the parameters of the VTF equation. It was demonstrated that at the same temperature, the ILs with short side chain cations, low charge density anions, and weak hydrogen bonding force between cations and anions usually exhibited high conductivity. Anions had a more obvious effect on conductivity than cations. The ionic association in the mixtures was affected not only by the species but also by the composition of the mixture.

The dilution enthalpies of four crown ethers, namely 12-crown-4, 15-crown-5, 18-crown-6, and 4,13-diaza-18-crown-6, in pure water and mixtures of N,N-dimethylformamide (DMF) and water of various mass fraction (w=0-0.3) were determined at 298.15 K by isothermal titration microcalorimetry. The corresponding enthalpic pairwise interaction coefficients (h_xx) were evaluated according to the McMillan-Mayer theory. Values of h_xx were all positive and large, which indicates that hydrophobic components predominate in crown-crown self-interactions. There are two main kinds of mechanisms: (1) When hydrophobic-hydrophobic interactions occur, cosphere overlapping reduces the formation of water structure, which makes a positive contribution to h_xx. (2) Hydrophobic-hydrophilic interactions increasingly destroy the water structure because of cosphere overlapping, which also makes a positive contribution to h_xx. In addition, h_xx values of the four crown ethers follow the order: h_xx(18-crown-6)>h_xx(4,13-diaza-18-crown-6)≈ h_xx(15-crown-5) >h_xx(12-crown-4), which indicates that the larger the size of the crown ether ring, the stronger the hydrophobic-hydrophobic interaction; namely, that crown ethers are subject to macrocyclic hydrophobic effects.

A complex of a rare-earth metal (Ho) nitrate with glycine (C₂H₅O₂N), Ho(NO₃)₃(C₂H₅O₂N)₄·H₂O, was synthesized, and characterized by chemical analysis, elemental analysis, and infrared (IR) spectroscopy. The thermodynamic properties of the complex were also studied. The low-temperature molar heat capacities at constant pressure (C_p,m) of the complex were measured using a high-precision automatic adiabatic calorimeter over the temperature range from80 to 390 K. The experimental molar heat capacities at constant pressure were used to deduce the polynomial equations for the heat capacity as a function of reduced temperature by applying the least-squares method to the two smooth stages of the curve. Based on the thermodynamic relationships among heat capacity, entropy, and enthalpy, the thermodynamic functions (H_T,m-H_298.15,m) and (S_T,m-S_298.15,m) were derived from the heat capacity data, with temperature intervals of 5 K. The molar enthalpy and entropy changes of the transition process at about 350 K (Δ_trsH_m and Δ_trsS_m) were calculated from the heat capacity curve. The thermal stability of the complex was determined using differential scanning calorimetry (DSC).

Low temperature heat capacities of the compound Zn(Met)₃(NO₃)₂·H₂O(s) have been measured by a precision automated adiabatic calorimeter over the temperature range 78-371 K. The initial dehydration temperature of the coordination compound was determined to be T_D=325.10 K by analysis of the heat-capacity curve. The experimental values of the molar heat capacities in the temperature region have been fitted to a polynomial equation of heat capacities with the reduced temperature (X), [X=f(T)], by the least squares method. Smoothed heat capacities and thermodynamic functions relative to the standard reference temperature 298.15 K of the compound are derived from the fitted polynomial equation and listed at 5 K internals. Using 100 mL of 2 mol·L^-1 HCl(aq) as calorimetric solvent, with an isoperibol solution-reaction calorimeter, the standard molar enthalpy of formation of the compound was determined to be Δ_fH_m⁰[Zn(Met)₃(NO₃)₂×H₂O(s), s]=-(1472.65±0.76) J·mol^-1 by a designed thermochemical cycle.