Thermal Stability, Smoke Density, and Flame Retardance of Ecotype Bio-Based Flame Retardant Agricultural Waste Bagasse/Epoxy Composites.

In the study, agricultural waste bagasse was used as a bio-based flame retardant for reducing the flammability of epoxy. Specifically, an interpenetrating network (IPN) was formed through a ring opening reaction between the hydroxyl functional group of bagasse and the epoxy group of triglycidyl isocyanurate (TGIC), forming Bagasse@TGIC. Next, 9, 10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (DOPO) was mixed with Bagasse@TGIC, inducing a reaction between the active hydrogen of DOPO and the epoxy group of TGIC, ultimately forming Bagasse@TGIC@DOPO with an IPN structure. Finally, the novel flame retardant was added to epoxy to create a composite. The integral procedural decomposition temperature (IPDT) of pure epoxy is 619 °C; after the introduction of the 30 wt% flame retardant, the IPDT of the resultant composite material increased to 799 °C, greatly increasing the thermal stability by 29%. After the addition of the Bagasse@TGIC@DOPO flame retardant, the limiting oxygen index increased from 21% for the pure epoxy to 29% for the composite, and the UL-94 rating improved from failing rating for the pure epoxy and V-0 rating for the composite. The Raman spectrum indicated that the addition of Bagasse@TGIC@DOPO IPN substantially increased the biochar yield during the burning process, increasing thermal stability. These results confirmed that the epoxy/Bagasse@TGIC@DOPO composite had substantial flame retarding effects.

A Study on Circular Economy Material Using Fish Scales as a Natural Flame Retardant and the Properties of Its Composite Materials.

Fish scales (FSs) are fishery wastes that can cause environmental pollution. This study aimed to solve this environmental problem. FSs were used as a flame retardant for polymer materials, making them valuable. Fish scales were combined with a commercial flame retardant, ammonium polyphosphate (APP), through synergistic effects to reduce the amount of commercial flame retardant. The use of FSs conforms to the concept of a circular economy and lowers costs by reducing the consumption of APP. Thermogravimetric analysis (TGA), integral procedural decomposition temperature (IPDT), pyrolysis kinetics, limiting oxygen index (LOI), the Underwriters Laboratories 94 (UL94) flammability test, scanning election microscopy, Raman spectroscopy, and energy-dispersive X-ray spectroscopy were used to determine the thermal properties, flame retardant properties, flame retardant mechanism, char morphology, and composition of the composites. The TGA results indicated that the addition of 40% flame retardant raised the char residue from 16.45 wt.% (pure EP) to 36.07 wt.%; IPDT from 685.6 °C (pure EP) to 1143.1°C; LOI from 21% (pure EP) to 30%; and UL94 classification from fail (pure EP) to V-0. These results suggest an increase in char residue, which indicates better protection of the polymer matrix material. The improvements in IPDT, LOI, and UL94 classification, which indicate greater thermal stability, lower flammability (from flammable to fireproof), and higher flammability rating (from fail to V-0), respectively, suggest that the composite material has favorable thermal properties and is less inflammable.

[Clinical Characteristics of Patients with Myeloid Sarcoma].

OBJECTIVE: To investigate the clinical characteristics, diagnosis and treatment methods of patients with myeloid sarcoma(MS)． Methods: The clinical data, laboratory examination, clinical pathology and treatment methods of 15 patients with MS treated in the First Affiliated Hospital of Wannan Medical College from June 2012 to January 2020 were retrospectively analyzed. RESULTS: Among the 15 cases of MS, including eight males and seven females, the middle age of patients were 53（19 to 72）. Among the 15 patients with MS, 4 showed solitary MS, while 11 showed secondary MS. Immunohistochemical results showed that MPO+（12/15）、CD68+（3/6）、Lys+（3/3）、CD34+（6/14）、TdT+（0/9）、CD43+（13/13）、CD117+（6/10）、CD15+（7/10）、CD3+（1/15）、CD20+（0/15）. 6 of 13 patients were survival till follow-up date．The median overall survival (OS) time was 16 months (1-88 months)．Conclusion: Myeloid sarcoma is rare and often secondary from acute myeloid leukemia(AML) and chronic myeogenous leukemia(CML). Isolated MS can easily be misdiagnosed as lymphoma. Treatment response should be evaluated in combination with bone marrow examination, PET/CT and other imagines．Systematic chemotherapy and hematopoietic stem cell transplantation are the main method to treat MS.

Thermal hazard investigation and hazardous scenarios identification using thermal analysis coupled with numerical simulation for 2-(1-cyano-1-methylethyl)azocarboxamide.

Polymers are salient participants in the current world, and roughly more than 40%-45% of all industrial polymers were produced by free radical polymerization. Azo-initiators now have been the foremost radical initiator with the virtue of low tendency to undergo chain transfer reactions. Nevertheless, azo-initiators are readily to decompose and release an immense amount of heats and gases under elevated ambient temperature. 2-(1-Cyano-1-methylethyl)azocarboxamide (CABN) was deliberately picked as an example for identifying the hazardous scenarios in the application of azo-initiators. Initially, thermal analysis technologies were used to investigate the thermal decomposition characteristics of CABN, and selected decomposition mechanism functions were verified for the best-fitting thermokinetic model. Subsequently, thermokinetic-based numerical simulations were implemented to evaluate the thermal hazards of CABN under the ideal adiabatic scenario. Process safety parameters under adiabatic conditions including time to maximum rate as well as induction period were consequently retrieved. Furthermore, inherent safety recommendations for free-radical polymerization were established to forestall the process accidents in storage and the applications of azo-initiator.

Use of magnetic fields and nitrate concentration to optimize the growth and lipid yield of Nannochloropsis oculata.

Microalgae produce increased lipid content accompanied by a significant decrease in cell density with decreasing nitrate concentration. Magnetic fields (MF) have been reported as a factor that could accelerate metabolism and growth in microalgae culture. Thus, this study aimed to optimize the influence of MF and nitrate concentration (sodium nitrate, N) on the growth and lipid productivity of Nannochloropsis oculata. A single-factor experiment integrated with response surface methodology (RSM) via central composite design (CCD) was performed. The results showed that the maximum specific growth rate (0.24 d-1) and maximum lipid productivity (38 mg L-1 d-1) obtained in this study were higher than those of the control culture (by 166% and 103%, respectively). This study also found that the two-way interaction term MF × N had a significant effect on cell growth but not on lipid production. It was concluded that to design appropriate MF for enhanced lipid productivity due to cell growth, further research must focus on developing an understanding of the relationship between the bioeffects of the magnetic field and the proteomic changes involved in lipid accumulation strategies. This approach would enable the design of conditions to obtain inexpensive high-value products from N. oculata.

Fire and explosion hazards of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide.

Ionic liquids (ILs) have very low volatility and are consequently considered as a green replacement to the organic solvents that have been widely used to date. The fire and explosion hazards of traditional organic solvents primarily depend on the combustibility of their vapors; therefore, ILs have been regarded as nonflammable for a long time because of their low volatility. However, recent studies have shown that ILs are flammable due to their thermal stability and consequently, the fire and explosion hazards of ILs limit their practical applications. The compound 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (abbreviated as [EMIM][Tf2N]) has been considered a potential candidate solvent for surfactant systems, but studies about the fire and explosion hazards of this IL are rare in the literature. In this study, the fire and explosion hazards of [EMIM][Tf2N] were explored in terms of different aspects. The auto-ignition temperature of [EMIM][Tf2N] was found to be 478 °C with an ignition delay time of 12.6 s. It was observed with the TGA/DSC system that the decomposition of [EMIM][Tf2N] was endothermic in a nitrogen atmosphere but exothermic in an air atmosphere. The dynamic TGA curves showed that the apparent activation energies were the same in both nitrogen and air atmospheres, but the dynamic DSC curves showed that the apparent activation energies were different in nitrogen and air atmospheres. The apparent activation energy inferred from the DSC curve in an air atmosphere was found to be the same as the apparent activation energy estimated by the Semenov theory of thermal ignition. Analysis of the gaseous decomposition products of [EMIM][Tf2N] by the TGA-FTIR system indicated that the exothermal effect in the air atmosphere was caused by the auto-ignition of acetylene (which is one of the gaseous decomposition products) and not by decomposition itself.

Thermal hazards of benzoyl peroxide and its derived process products through theoretical thermodynamics assessment and different calorimetric technologies.

Benzoyl peroxide (BPO) is one of the primary OPs used as an initiator, curing agent, or medicine. Some of the plastic processes use BPO without air for maintaining the efficiency of the entire reaction. However, there have been numerous accidents involving BPO in petrochemical plants, especially those related to fire and explosion, that are due to its unstable thermal properties and peroxy bond (OO). BPO can be identified as a typical substance with autocatalytic reaction characteristics. Therefore, the related processes and their products are critical to prevent these kinds of chemical contingencies. This research was based on two types of instruments (nonisothermal and isothermal calorimetry), and theoretical methods to further determine the thermal hazard level. From the experimental results for BPO and BPO mixed with its by-products, the heat of decomposition was much higher (from 800 to 1235 J/g), the time to maximum rate under isothermal conditions was much shorter (from 99.1 to 17.4 h at 75.0 °C), and the apparent activation energy was much lower (from 118 to 91 kJ/mol) after BPO was mixed with its by-products. Therefore, the hazard level of BPO mixed with its by-products from the reaction process was much higher than that of pure BPO.

Improving Thermal Stability of Polyurethane through the Addition of Hyperbranched Polysiloxane.

Polydimethylsiloxane with hydroxy groups was functionalized to form functionalized polydimethylsiloxane, which subsequently underwent an addition reaction with isophorone diisocyanate to form the prepolymer. Next, 3-aminopropyltriethoxysilane (APTS) reacted with 3-glycidoxypropyltrimethoxysilane (GPTS) to produce bridged polysilsesquioxanes, and sol-gel technology was employed to form hyperbranched polysiloxane nanoparticles with hydroxy groups, APTS-GPTS, which was used as the additive. The hyperbranched polysiloxane and the prepolymer containing NCO functional groups then underwent an addition reaction to produce the hybrid materials. Fourier-transform infrared spectroscopy and 29Si nuclear magnetic resonance were used to characterize the structure of the polyurethane hybrid. Regarding thermal stability, after the hyperbranched polysiloxane nanoparticles was introduced, the integral procedural decomposition temperature increased from 348 °C for polyurethane matrix to 859 °C for the hybrid material. The results reveal that the thermal stability of the hybrid material substantially increased by approximately 247%.

Experimental and numerical simulation study of the thermal hazards of four azo compounds.

Azo compounds (azos) possess diverse exothermic properties that enable their application in numerous industrial processes, but these properties also engender a corresponding diversity of thermal hazard profiles. This study employed an innovative approach to determine the specific thermal reactions and decomposition hazard profiles of azos. Four typical azos (AIBN, AMBN, ABVN, and AIBME) were assessed using three thermal calorimetry techniques, and results were subsequently analyzed using a nonlinear optimization model. Thermal hazard analysis of small-scale experiments indicated that AIBN had a heat decomposition of 1247 J/g and a maximum pressure increase of 367 psig and thus exhibited more hazardous characteristics than did AMBN, ABVN, and AIBME. This study also obtained the relevant process safety parameters, time to maximum rate, onset and peak temperature, adiabatic temperature rise, and rate of pressure increase to use for later scaled-up applications. The findings of this study can be used to develop a predictive model for the thermal behavior of azos and to provide the necessary basis for the design and selection of precise treatment and appropriate safety systems.

Effects of UV for Cycloaliphatic Epoxy Resin via Thermokinetic Models, Novel Calorimetric Technology, and Thermogravimetric Analysis.

The cycloaliphatic epoxy resin selected for this study was 3,4-epoxycyclohexane methyl-3'4'-epoxycyclohexyl-carboxylate (EEC). Epoxy resin has numerous applications, such as varnishes, tires, and electronic materials. However, the extensive used of chlorofluorocarbon (CFC) compounds in the last century has resulted in the formation of a hole in the ozone layer. As a consequence, solar radiation is intensifying gradually; therefore, continuous irradiation by sunlight should be avoided. The results of solar radiation can exacerbate the deterioration and photolysis of compounds. Through thermogravimetry and differential scanning calorimetry, the apparent onset temperature of EEC and EEC was analyzed under UV radiation for different durations. Thermokinetic data were used to determine the parameters of thermal decomposition characteristics through simulation to assess the reaction of EEC and EEC under UV radiation for different durations. The goal of the study was to establish the parameters of thermal decomposition characteristics for the effects of UV on EEC, as well as the probability of severity of thermal catastrophe.

Preparation and Flame Retardance of Polyurethane Composites Containing Microencapsulated Melamine Polyphosphate.

A new microencapsulated flame retardant containing melamine polyphosphate (MPP) and 4,4'-oxydianiline-formaldehyde (OF) resin as the core and shell materials, respectively, was synthesized by in situ polymerization. 29Si NMR was used to measure the condensation density of polyurethane containing silicon compound (Si-PU). The structures and properties of the microencapsulated melamine polyphosphate (OFMPP) were characterized using X-ray photoelectron spectroscopy, scanning electron microscopy and water solubility. Thermal behavior of the OFMPP was systematically analyzed through thermogravimetric analysis. Flame retardance tests such as the limiting oxygen index and UL-94 were employed to evaluate the effect of composition variation on the MPP and OFMPP in polyurethane composites. The results indicated that the microencapsulation of MPP with the OF resin improved hydrophobicity and that the flame retardance of the Si-PU/OFMPP composite (limiting oxygen index, LOI = 32%) was higher than that of the Si-PU/MPP composite (LOI = 27%) at the same additive loading (30 wt %).