Thermal Decomposition Process Research Articles

Visible-Light-Active Vanadium and Copper Co-Doped gCN Nanosheets with Double Direct Z-Scheme Heterojunctions for Photocatalytic Removal of Monocrotophos Pesticide in Water

In this study, both vanadium and copper elements were anchored on graphitic carbon nitride (gCN) (denoted as V/Cu/gCN) via a thermal decomposition process as a novel nanosheet photocatalyst for the removal of monocrotophos (MCP). The prepared nanosheet features were studied by utilizing XRD, UV–Visible absorption spectrometry, PL, FE-SEM, TEM, and XPS techniques. These analytical techniques revealed the successful formation of direct Z-scheme heterojunctions of V/Cu/gCN nanosheets. The dopant materials significantly enhanced the electron–hole separation and enhanced the removal rate of MCP as compared with bulk gCN. The investigation of effective operating conditions confirmed that a higher removal of MCP could be obtained at a doping concentration of 0.3 wt% and a catalytic dosage of 8 mg with 80 min of visible-light irradiation. The generation of various reactive radicals during the degradation process of the photocatalyst was observed using a scavenging treatment process. Additionally, the scavenging process confirmed that e−, OH•, h+, and O2•− played a major role in MCP degradation. The direct Z-scheme dual-heterojunction mechanism, as well as the possible pathway for the fragmentation of MCP by the V/Cu/gCN nanosheet photocatalyst, was derived in detail. This research article provides a novel perspective on the formation of excellent semiconductor photocatalysts, which exhibit enormous potential for environmental treatments.

Thermal Decomposition, Ignition Process and Combustion Behavior of Nitrate Ester Plasticized Polyether Propellant at 0.1–3.0 MPa

Nitrate ester plasticized polyether (NEPE) propellant is widely used in solid rocket motors, having both good mechanical properties and high specific impulse. However, its ignition and combustion process are complex and need to be better understood. In this study, a high-pressure sealed combustion chamber was constructed, a thermogravimetry-differential scanning calorimetry was used to investigate the thermal decomposition process, and a high-speed camera was used to capture the ignition process and combustion behavior of the propellant. The results showed that the thermal decomposition process of this propellant could be divided into two stages. The first stage (50–350°C) was the major mass loss stage and exhibited typical features of BTTN, RDX, and AP decomposition. The second stage (350–500°C) was mainly accompanied by decomposition of the remaining components as well as slight oxidation of aluminum particles. The ignition process of NEPE propellant was divided into four stages, including the inert heating period stage, thermal decomposition stage, initial flame stage, and stable combustion stage. After the propellant absorbed heat, the propellant started to pyrolyze and gasify to generate flammable gas. When the temperature of the propellant surface reached the flammable gas ignition point, an initial flame was generated on the surface, which spread rapidly, covering the surface. The ignition delay time of the propellant was measured by a signal acquisition system, and a mathematical model was then established for the ignition delay time. The results showed that the ignition delay time decreased with increased laser heat flux and ambient pressure. Finally, the Vielle burning rate empirical formula was used to fit the burning rate data for the propellant. The resulting good fit was consistent with experimental measurements and showed that the formula was valid for predicting the NEPE propellant burning rate under 0.1–3.0 MPa nitrogen.

Alkali-assisted facile and scalable preparation of fluorescent sulfur-doped carbon dots with excellent optical and biological properties from thioctic acid

The preparation of high-performance heteroatom-doped fluorescent carbon dots (CDs) from renewable biomass or biometabolites hold an extensive attention. Here, we report an excess sodium hydroxide (NaOH) assisted method for the preparation of sulfur-doped carbon dots (S-CDs) at lower temperatures by using thioctic acid (TA). Excessive NaOH can promote the thermal decomposition process of thioctic acid in the hydrothermal process, thereby realizing rapid reaction rate (critical time 1 h) and scalable synthesis at low temperature (120 °C). The amount of NaOH and the reaction time were identified as the main factors affecting the synthesis, and the reaction of NaOH with disulfide bonds contributed the most to the generation of fluorescent S-CDs. This in-situ sulfur doping process resulted in excellent fluorescence properties, high relative quantum yield of 11.5%, low biotoxicity, good biocompatibility and excellent solubility, etc. In addition, this as-prepared fluorescent S-CDs showed excellent concentration dependence on ferric ions (Fe3+) and can achieve high-precision and selective detection. This work may provide a high-efficiency synthesis strategy for S-CDs for biological and detection applications.

Reactive molecular dynamics studies of the interfacial reactions of core-shell structured CL-20-based aluminized explosives at high temperature

The thermal decomposition processes of CL-20 nanoparticle (NP), core-shell structured CL-20@Al NP, and CL-20@AlO NP were studied through reactive molecular dynamics simulations. The results are as follows: (1) the CL-20@Al and CL-20@AlO NPs decomposed earlier than the CL-20 NP; (2) the Al shell experienced the melting-aggregation process and gradually changed from a shell structure to block aluminized clusters; (3) different in the decomposition of the CL-20 NP, N2 appeared first in the decomposition of the CL-20@Al and CL-20@AlO NPs, indicating that Al changed the initial decomposition process of CL-20; (4) the quantities of NO2, NO, and CO2 produced during the decompositions of the CL-20@Al and CL-20@AlO NPs were much lower than those produced during the decomposition of CL-20 NP. This occurred because the Al atoms had high activity at high temperature and attacked these products to produce massive aluminized substances; (5) Al significantly promoted the movement of H and N atoms but impeded that of O and C atoms in the three systems. This study will present fundamental information about the interfacial behaviors of aluminized explosives.

Thermal decomposition and interaction mechanism of HFC-134a/HFC-32 mixture in Organic Rankine Cycle

Organic Rankine Cycle (ORC) is an effective technology for the recovery of industrial waste heat and the utilization of renewable energy to produce electricity. Hydrofluorocarbon mixtures are more attractive used in ORC systems than pure working fluids due to the advantages of higher work outputs, higher cycle efficiencies, and lower exergy losses. For the supercritical ORC system, thermal stability is one of the main factors to screen the working fluids. In the present work, ReaxFF reactive molecular dynamic simulations and density functional theory calculations are performed to investigate the thermal decomposition and interaction mechanism of HFC-134a/HFC-32 mixture. The thermal decomposition process, the effects of temperature, and HFC-134a to HFC-32 ratio on the thermal decomposition of HFC-134a/HFC-32 mixture, and the interaction between HFC-134a and HFC-32 are investigated. The results showed that the hydrogen bond formed between HFC-134a and HFC-32 in HFC-134a/HFC-32 mixture, which inhibits the decomposition of HFC-134a. The HFC-134a/HFC-32 mixture used in ORC system has a better thermal stability than pure HFC-134a. The results of this study are beneficial to the screening of ORC working fluid and the safe operation of the ORC system.

Tailoring Thermal and Electrical Properties of Jeffamine Segmented Polyetherimide Composite Films Containing BaTiO3 particles.

The continuous advancement of materials science has highlighted the ongoing need for additional studies on the main composite materials topics, particularly in the field of multifunctional nano-composites, towards improving their capability to meet multifaceted requirements in order to stimulate both scientific and technological development. In this study, we report the preparation and characterization of polyetherimides (PEIs) derived from 4,4'-(4,4'-isopropylidenediphenoxy) bis (phthalic anhydride) following a two-step polycondensation reaction using either 4,4'-(1,3-phenylenedioxy) dianiline, or Jeffamine ED-600 as comonomers, or a mixture of the two diamines. Based on the PEI containing flexible Jeffamine segments, polymer composite films were developed by incorporating BaTiO3 particles. The chemical structure and morphology of the composite films were investigated by FTIR spectroscopy and scanning electron microscopy. Thermal properties were determined by thermogravimetric analysis and differential scanning calorimetry. The influence of Jeffamine segments on the thermal decomposition process was investigated by TG/MS/FTIR measurements under air and nitrogen atmospheres. Based on the obtained data, the thermal decomposition mechanism was established and is discussed in accordance with the chemical structures of the polymers. The surface properties of the PEI and PEI-composite films were characterized by performing contact angle measurements. The addition of BaTiO3 increased the wettability of the surfaces. The dielectric characteristics of polymer composite films were investigated by broad band dielectric spectroscopy measurements. It was noticed that the addition of BaTiO3 nanoparticles to the copolymer matrix gradually enhanced the dielectric constant of the composites.

Synthesis and structural characterization of β-(NH4)2Mo4O13 by direct “reducing ammonium” in situ transformation method

A new environmentally friendly strategy for the synthesis of β-(NH4)2Mo4O13 powders is presented using a direct “reducing ammonium” in situ transformation method from (NH4)2Mo2O7. The crystal structure of the resulting β-(NH4)2Mo4O13 was first characterized using X-ray diffraction analysis. The title compound crystallizes in a triclinic system, space Group P-1(2), a = 8.250 Å, b = 8.331 Å, c = 10.240 Å, α = 104.686°, β = 106.077°, γ = 109.614°, Z = 2. The TG-DTA results showed that no intermediate products were generated in the thermal decomposition process from β-(NH4)2Mo4O13 to MoO3. A comprehensive study of the newly synthesized β-(NH4)2Mo4O13 was performed by FESEM, FTIR spectroscopy and Raman spectroscopy. The band gap energy of the synthesized β-(NH4)2Mo4O13 was 3.26 eV, which shows a good intense absorption band in the visible light region.

Comprehensive study on thermal decomposition mechanism and interaction of 3-Nitro-1,2,4-Triazol-5-One/Poly-3-nitromethyl-3-methyloxetane plastic bonded explosives

In this paper, the thermal decomposition process of 3-Nitro-1,2,4-Triazol-5-One (NTO)/Poly-3-nitromethyl-3-methyloxetane (Poly-NIMMO) based Plastic Bonded Explosives (PBXs) at five temperatures from 2500 K to 3500 K was simulated based on the reactive molecular dynamics, and some related analysis contents were supplemented and verified by first-principles and quantum chemistry methods. In particular, given the strong acidity of NTO explosive, the interaction between NTO and Poly-NIMMO was analyzed. The analysis results of the atoms in molecules (AIM) method and Independent gradient model based on Hirshfeld partition (IGMH) method show that there are some relatively strong hydrogen bonds between them. The activation energies of the initial decomposition stage and the intermediate decomposition stage of the mixed system are 60.37 kJ∙mol−1 and 98.37 kJ∙mol−1. Compared with the pure NTO system, the activation energies of the two stages decrease to a different extent. Poly-NIMMO in the mixed system brings a lot of NO2 and OH groups, these molecular fragments and groups will have chemical reactions with NTO and decomposition products of NTO, resulting in the reduction of the number of hydrogen transfer reactions between NTO molecules. By comparing the quantity of products, it can be found that the content of H2O is greatly increased. The curve reaches the peak in a shorter time, and the decomposition reaction rate of the system is faster. The amount of CO2 did not increase too much, and more C atoms gathered to form clusters. The changes of the number of bonds verify the above analysis. In addition, in a certain temperature range, the relationship between the maximum number of clusters and temperature is positively correlated, but the excessive temperature can inhibit the maximum number of clusters. The ratio of O, N, H atoms to C atoms in the cluster after equilibrium at five temperatures is H/C > N/C > O/C. There is no doubt that Poly-NIMMO will reduce the acidity of the system, but it will promote the thermal decomposition of NTO and reduce the insensitivity of PBXs to thermal stimulation.

Mechanisms of the Action of Fire-Retardants on Reducing the Flammability of Certain Classes of Polymers and Glass-Reinforced Plastics Based on the Study of Their Combustion.

In the present review, using an integrated approach based on the experimental and theoretical study of the processes of thermal decomposition and combustion of practically important polymers, such as polymethyl methacrylate, polyethylene, and glass-fiber-reinforced epoxy resin, the features of the mechanism for reducing the combustibility of these materials with phosphorus-containing flame-retardants (FR), as well as graphene, are identified. A set of original experimental methods was developed and applied that make it possible to study the kinetics of thermal decomposition and the thermal and chemical structure of the flames of the studied materials, including those with FR additives, as well as to measure the flame propagation velocity, the mass burning rate, and the heat fluxes from the flame on the surface of a material. Numerical models were developed and tested to describe the key parameters of the flames of the studied polymeric materials. An analysis of the experimental and numerical simulation data presented showed that the main effect of phosphorus-containing fire-retardants on reducing the combustibility of these materials is associated with the inhibition of combustion processes in the gas phase, and the effect of adding graphene manifests itself in both gas and condensed phases.

Investigation of micro/nano formation mechanism of porous graphene induced by CO2 laser processing on polyimide film

Laser-induced graphene (LIG) prepared from polyimide (PI) films via a facile CO2 laser-writing technique, has garnered considerable application prospects in micro-supercapacitors, intelligent sensors, and flexible electronics. To achieve the controllable fabrication of LIG, it is essential to understand the micro/nano formation mechanism of LIG. Herein, we explored the micromorphology evolution law, Raman characteristics, primary elements content distribution, and main electron peaks variation of LIG. The experimental results reveal that i) the irradiation region presents a typical crater-like structure accompanied by abundant three-dimensional networks; ii) the low laser power of 3.89 W (9.9 %) is conducive to the formation of high-quality LIG with a small ID/IG; iii) the excessive laser power over 4.15 W (>10 %) provokes element recombination between unstable carbon bonds (C–/C=) and oxygen in the air to reduce the relative carbon content; iv) too high temperature destroys the stability of the graphene structure, resulting in cracks, holes, and defects. Based on the abovementioned findings, we concluded the thermal decomposition process of PI and the local reaction mechanism of LIG. Finally, we realized the controllable fabrication of high-performance LIG with an ultra-small ID/IG (0.3), an extremely high carbon content (94.49 %), and the prominent wetting affinity along with permeability for a water-based electrolyte.

Pyrolysis of Precious Chinese Xuan Paper Containing Ammonium Phytate as a Flame Retardant.

Xuan paper with outstanding cultural and artistic values is one of the most precious Chinese handmade papers and is widely used in traditional calligraphy and painting. However, the highly combustible cellulosic raw materials of Xuan paper present potential fire hazards. Ammonium phytate (AP) originating from biosourced phytic acid has been used for the flame-retardant treatment of Chinese Xuan paper by facile spray coating. The limiting oxygen index value of the treated Xuan paper increased to higher than 40%, demonstrating that the flammability of Xuan paper was greatly reduced by this treatment. The excellent flame retardancy afforded by this treatment was confirmed by cone calorimetry. TGA was used to demonstrate that the presence of AP changed the thermal decomposition process to promote char formation during the degradation of Xuan paper. The flame-retardant mode of action of phytate-coated Xuan paper was investigated using TG-FTIR, SEM, and XPS spectra. A P–N cooperative effect was proposed to account for both the condensed phase and gas-phase flame-retardant actions. The phosphorus component promotes char formation in the condensed phase, while the nitrogen component releases inert species to dilute the fuel load in the gas phase. The ink-wetting property of the coated Xuan paper was influenced negligibly by the coating process. The development of fire-resistant Xuan paper using ecofriendly flame retardants through simple and convenient spray coating has been demonstrated.

A new ternary copper (Ⅱ) complex of 2,4-dihydroxybenzoic acid: Synthesis, crystal structure and its catalytic decomposition effect on AP and RDX

In order to solve the unclear problems of structure and composition for 2,4-dihydroxybenzoic acid (2,4-DHBA) copper salt (β-Cu), a new insoluble ternary copper (Ⅱ) complex of 2,4-DHBA ([Cu(C12H8N2)2(C7H5O4)](C7H5O4)) was designed and synthesized in water. The ternary complex crystallizes in the monoclinic system with the space group P21/n. The central Cu2+ is coordinated with four nitrogen atoms from two 1,10-phenanthroline ligands and one carboxyl oxygen atom from a 2,4-DHBA anion. The other 2,4-DHBA anion does not participate in coordination and only provides the action of balance charge. In addition, compared with β-Cu, no water molecules exist in the ternary complex. The thermal stability of the ternary complex was investigated, as well as its catalytic decomposition activity on AP and RDX. With the addition of the ternary complex, the exothermic decomposition peak temperatures of AP and RDX were reduced from 406.5 to 353.9 ​°C, and 242.3 to 181.4 ​°C respectively, and the apparent activation energies were reduced from 293.1 to 207.4 ​kJ ​mol−1, and 239.6 to 177.5 ​kJ ​mol−1, respectively. Moreover, the addition of the ternary complex has greatly improved the heat release of AP and RDX. The catalytic decomposition performance of the new ternary complex on AP and RDX is much better than that of the traditional β-Cu. Moreover, the new copper (Ⅱ) complex completely changed the thermal decomposition process of RDX from melting decomposition to direct solid phase decomposition, and such catalytic effect is uncommon. Therefore, the new ternary copper (Ⅱ) complex presents a better potential application for modified double-base propellant of RDX.

In Situ Generating CaCO3 Nanoparticles Reinforced Nonflammable Calcium Alginate Biocomposite Fiber.

Petroleum-based synthetic flame-proof fiber releases toxic volatile organic compounds in thermal decomposition process and has other problems, like tickling feeling and high density. A natural polysaccharide, calcium alginate, is an intrinsic fire-resistant biodegradable material, but its limited mechanical performance prevents it from being a practical flame-retardant fabric. To address this problem, Na2CO3 was doped into alginate spinning solution to obtain in situ generating CaCO3 nanoparticle-reinforced alginate fiber by microfluidic spinning technique. Comparative analysis illustrated that incorporation of 0.50% Na2CO3 into the fiber greatly improved its mechanical performance; meanwhile, in situ generated CaCO3 nanoparticles also throttled oxygen and heat flow in burning, endowing the fiber with excellent flame retardancy. The prepared composite fiber released less heat, smoke, and toxic volatile organic compounds in burning, which reduced the fire hazard. The formed residue char and pyrolysis products functioned as the physical barrier and displayed a synergistic effect to inhibit oxygen and heat transmission and impede the further combustion. All of the results demonstrate that the obtained fiber exhibits a good mechanical and flame-retardant performance, making it an ideal candidate as a fire-protection textile.

Pyrolysis of hybrid polyurethane inorganic thermal insulation: thermogravimetric analysis and FTIR spectra

Purpose. The purpose of this work is to study the process of thermal decomposition (pyrolysis) of two samples of a hybrid organic-inorganic (OIH) heat-insulating material based on data obtained by thermogravimetric analysis and IR-Fourier spectrometry. The goal set predetermined the following research tasks: to find out the basic chemical structure of the OIH samples (by functional groups), to study the order of processes in materials when heated in nitrogen, to calculate the activation energy, the pre-exponential factor, to determine the pyrolysis mechanism. Methods. The methods of thermogravimetric analysis and IR-Fourier spectrometry were used in the work. Samples for spectrometric analysis were prepared in the process of thermogravimetric tests using the “freezing” experiment method. Results and discussion. The paper studies the structural features of two samples of hybrid polyurethane inorganic (OIH) thermal insulation material and traces the physicochemical processes that occur when they are heated under dynamic conditions in a nitrogen atmosphere up to 750 °C. The multi-stage nature of the pyrolysis of the OIH material is shown. The pyrolysis of the first sample is a threestage process. For the second sample, decomposition proceeds in two stages. All stages are endothermic. This indicates the predominance of energy costs for breaking bonds between the organic and inorganic parts and other conclusions. It has been established that the pyrolysis of OIH samples at all stages is carried out according to the mechanism of nucleation and the growth of nuclei (active centers of destruction). Analysis of the IR spectra of the samples showed that both samples were prepared using Desmodur aliphatic isocyanates. Conclusions. The paper studies the chemical structure and physicochemical changes when heating the new group of materials — hybrid organic-inorganic (OIH) heat-insulating materials. The article is a continuation of a team of authors systematic study of a thermal behavior of modern types of polymer thermal insulation.

Effects of liquid accelerant on the pyrolysis behaviors and kinetics of PMMA, a noncharring polymer

AbstractThermal decomposition of solid combustibles infiltrated with combustible liquids (liquid accelerants) is one typical fire behavior in arsons. In the present study, thermogravimetric and kinetic analyses are used to investigate the pyrolysis of one typical noncharring polymer namely polymethyl methacrylate (PMMA) infiltrated with different contents of one representative liquid accelerant namely kerosene. Results indicate that the thermal decomposition process of pure PMMA and PMMA infiltrated with kerosene show a one‐stage and a three‐stage process, respectively. Furthermore, the first and third stages for PMMA infiltrated with kerosene can be both regarded as one‐step reaction. With the increase of kerosene content, the conversion rate ranges of the first and third stages for PMMA infiltrated with kerosene are shortened. The peak and average reaction rates of the first and second stages increase, while the peak and average reaction rates of the third stage decrease. The maximum and average reaction rates for the entire decomposition process also decrease. The average activation energy values for the whole and one certain stage both increase. Moreover, the calculated kinetic parameters can be used to accurately predict the thermal decomposition behavior of PMMA infiltrated with kerosene.

Equilibrium, DNA binding, docking, and antimicrobial studies of Ni(II) and Cu(II) chelates with 1‐(4′‐nitrobenzoyl)‐3‐thiosemicarbazide

Ni(II) and Cu(II) chelates of 1‐(4′‐nitrobenzoyl)‐3‐thiosemicarbazide (PNBTSC, HL) were synthesized and characterized by liquid chromatography‐mass spectrometry (LC–MS), thermogravimetric analysis (TGA), infra‐red (IR), UV–visible, and electron spin resonance (ESR) spectral techniques, which revealed the tetragonally distorted octahedral geometry around the central metal ion in both the chelates. The kinetic and thermodynamic properties were calculated using the Coats–Redfern relation. Thermal decomposition processes of chelates indicate the thermally stability of the chelates. The optimized molecular geometry, atomic charges, energies of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO), and energy gap 0.11203 eV of HL have been studied by density functional theory (DFT) calculations, which revealed the soft nature and high reactivity of the compound. Equilibrium studies of the 1‐(4‐nitrobenzoyl)‐3‐thiosemicarbazide with Ni(II) ion in 70% v/v DMF‐water medium have been evaluated. The pKa value of HL was found to be 7.1, and the values indicated the formation of 1:1 and 1:2 chelates in solution. DNA binding affinities of synthesized metal chelates with calf thymus DNA using UV absorption spectroscopy, spectro‐fluorimetry, and viscosity measurements revealed hypochromism and intercalative mode of binding. The Kb values from the absorption studies are 5.00 × 106 and 3.33 × 106 M−1, and Ksv values from fluorescence studies are 0.108 and 0.395 M−1 for chelates 1 and 2, respectively. The cleavage of supercoiled pBR33 DNA without any additives was studied using gel electrophoresis method which exhibited hydrolytic cleavage of plasmid DNA. Molecular docking studies carried out for the complexes also inferred intercalative mode of binding with DNA. The inhibition constants for HL, 1, and 2 are 107.09, 21.66, and 184.45 μM, respectively. Ligand and its metal chelates screened for antimicrobial activity against Gram positive and Gram negative bacteria revealed higher activity in chelates.

The Application of N, N -bis(Isonicotinic Acid) 1, 4-Naphthalenedicarboxylic Acid Dihydrazide in Biodegradable Poly(L-lactide): Crystalline Nucleation, Melting Behavior, Thermal Stability and Mechanical Properties

Improving the crystallization performance of poly(L-lactide) (PLLA) is necessary to adapt for various applications. In the current work, N, N -bis(isonicotinic acid) 1, 4-naphthalenedicarboxylic acid dihydrazide (NAIAH) was synthesized to be firstly aimed at promoting the crystallization of PLLA, and the NAIAH-nucleated PLLA materials were prepared using PLLA as a matrix material and NAIAH as a nucleating agent, and the crystalline nucleation, melting behavior, thermal decomposition and mechanical properties of PLLA/NAIAH samples were investigated by the relevant testing instruments. The results from the non-isothermal melt-crystallization from the melt of 190oC indicated that the NAIHA could significantly accelerate PLLA�s crystallization, and played an efficient heterogeneous nucleation in PLLA�s crystallization. The effect of different final melting temperatures on PLLA�s melt-crystallization behavior showed that a relatively low final melting temperature was beneficial for the crystallization of PLLA, and the 170oC was the optimum final melting temperature in this study. An increase of cooling rate could weaken PLLA/NAIAH�s crystallization ability, but the NAIAH was still able to promote PLLA�s crystallization upon the fast cooling at 50oC/min, showing a powerful crystallization accelerating effect of NAIAH. PLLA/NAIAH�s melting behaviors after different crystallization conditions were affected by heating rate and crystallization temperature, and the double melting peaks appeared in melting DSC curves were assigned to melting-recrystallization. Thermal decomposition processes in air showed that the NAIAH decreased PLLA�s thermal stability, but the interaction of PLLA with NAIAH had an inhibition for a drop in onset decomposition temperature. Additionally, the introduction of NAIAH dramatically reduced PLLA�s tensile modulus and elongation at break.

Thermal Decomposition of GAP Studied by Dynamic Pressure-measuring Thermal Analysis

The thermal decomposition process of GAP in a vacuum confined space was measured by Dynamic Pressure-measuring Thermal Analysis(DPTA). In order to avoid the test error, the test process was improved: the method of liquid nitrogen condensation was used to prevent GAP volatilization in the process of vacuum pumping in the reaction test tube, and the vapor pressure at different temperatures was measured by thermogravimetric analysis. The results show that at 80°C to 120°C, the mechanism function of GAP non-isothermal decomposition reaction is Jander equation, the apparent activation energy is 159.8kJ·mol-1, and the pre-exponential factor lnA is 25.8. At the GAP isothermal reaction stage, the mechanism function changes with the temperature. When the temperature increases, the thermal decomposition reaction changes from diffusion reaction to activation reaction. The decomposition rate constant K increases exponentially with increasing temperature. When T=80°C, K=1.27×10-6; when T=120°C, K=36.93×10-6. According to the data of the decomposition time of 0.1% in the temperature range of 80~120 °C, the Semenov equation is lntT = 19039.90/T- 43.012. The storage life is 35.96 years at 25°C.

Kinetic Analysis of Thermal Decomposition Process of Emulsion Explosive Matrix in the Presence of Sulfide Ores

This study aims to characterize the whole reaction process of (i) emulsion explosive matrix and sulfide ores, and (ii) ammonium nitrate and pyrite by the thermodynamics analysis method. A series of experiments were carried out at atmospheric pressure from 25 °C to 350 °C at four heating rates (3, 5, 10, and 15 K/min) and the Coats–Redfern method was applied to calculate the apparent activation energy of samples at different heating rates. The results show that the thermogravimetric (TG) curve of sulfide ores and emulsion explosive matrix can be divided into four stages: the water evaporation stage, the dynamic balance stage, the thermal decomposition stage, and the extinguishment stage. However, the thermal decomposition process of ammonium nitrate and pyrite can be divided into the dynamic balance stage, the thermal decomposition stage, and the burnout stage. The ignition temperature (T0) and maximum peak temperature (Tm) of the samples increased with the heating rate, but the shape of the TG/DTG (Derivative Thermogravimetric) curve was not affected. The results show that the reaction process of sulfide ores and emulsion explosive matrix is similar to the reaction process of pyrite and ammonium nitrate. The thermal stability of emulsion explosive matrix decreases when sulfide ores are added. By contrast, when pyrite is added, the thermal stability of the ammonium nitrate decreases more significantly.

A Review on Pyrolysis for Sustainable Biomass Conversion

The use of bio-energy is rapidly increasing which is become a crucial significant way to replace fossil fuel. The depletion of fossil fuels is responsible for initiating the utilization of the sustainable energy which has been available surrounding human beings. The employment of such sustainable energy can be possible from waste procreated by living creatures and that is feasible because of thermal decomposition processes, which comprise the gasification, combustion, and pyrolysis process for the production of biochar. The present study portrayed the very promising thermal decomposition process that is the pyrolysis process. The two main pyrolysis processes explained where basic feedstock is biomass invested. This feedstock may have diverse versions as natural live or dead plants, wastage of animals, organic waste, etc. All these feedstocks are responsible for the emission of some amount of carbon which relates to the different modes of operation used in the pyrolysis biomass conversion process. The bioproduct varies due to the effect of various operating conditions such as temperature, heating rate, feedstock, reactors configuration, and reaction time. Demand for bioproducts rising in daily life Due to this circumstance Sustainability of products become prominent while exploited in the proper application such as soil amendment, soil fertility, climate change mitigation, and waste management. This review demonstrates the pyrolysis process to convert simple biomass to sustainable biochar, bio-oil, and syngas with the variation of the amount of product depending on different pyrolysis processes.