Thermogravimetric Analysis Data Research Articles

Phosphorous containing poly(amidoamine-organosilicon) (P@PAMAMOSi) flame retardants: Synthesis and sol-gel application on cotton fabrics

A novel hyperbranched phosphorous containing poly(amidoamine-organosilicon) (P@PAMAMOSi) was successfully synthesized and the structure was characterized by fourier transform infrared spectra (FT-IR) and NMR. The cotton fabrics were wrapped with P@PAMAMOSi by sol-gel method. The P@PAMAMOSi modified cotton fabrics were proven by FT-IR and scanning electron microscopy (SEM). The thermal stability and combustion properties of the blank cotton and treated cotton fabrics were explored by thermogravimetric analysis (TGA), limiting oxygen index (LOI), vertical flammability, and cone calorimetry. The data of TGA indicated that modified cotton fabrics have exquisite thermal stability, when the temperature reached 700 °C, the char residues of A30 treated cotton, B30 treated cotton, and C30 treated cotton were 29.5, 34.5, and 28.8 %, respectively; which is better than the 12.7 % of blank cotton. The results were verified by the LOI and combustion tests of cotton fabrics. The flame-retardant mechanism of treated cotton fabrics was analyzed by the FT-IR, X-ray photoelectron spectrometry (XPS), SEM, and energy dispersive X-ray spectroscopy (EDS), the treated cotton fabrics showed condensation phase and gas phase flame retardant mechanism. In addition, treated cotton fabrics showed desirable physical properties and mechanical properties.

Cyclodextrin metal-organic framework@SiO2 nanocomposites for poorly soluble drug loading and release.

The development of non-toxic drug carrier materials with high loading capacity, sustained release properties, stability, and biocompatibility holds significant medical value and potential for loading and releasing poorly soluble drugs. In this study, we synthesized a biocompatible, non-toxic, environmentally friendly CD-MOF porous material with high specific surface area and tunable structure. By incorporating SiO2 to enhance the stability of MOF materials, the synthesized CD-MOF@SiO2 material shows promising applications in drug delivery. The obtained CD-MOF@SiO2 nanocomposite was utilized as a carrier for the poorly soluble drug, folic acid. Characterization of the drug-loaded composite before and after drug loading was performed using scanning electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, N2 adsorption-desorption, and X-ray diffraction analyses, showing improved stability as indicated by thermogravimetric analysis and derivative thermogravimetry data. UV spectrophotometry was used to investigate the loading and sustained release of folic acid under different conditions in PBS buffer, demonstrating that the well-structured CD-MOF@SiO2 material exhibits high drug loading and controllable release properties. The CD-MOF@SiO2 achieved a high drug loading efficiency (166.78%) and encapsulation rate (83.39%) for folic acid, leading to a significant increase in apparent solubility from 1.6 μg mL-1 in its free form to 21.74 mg mL-1, a 13 588-fold expansion. This work presents a novel, efficient, and highly valuable approach for the development of carrier materials for loading and releasing poorly soluble drugs.

Characterization of pyrolysis behavior for rigid polyurethane foam wastes with different densities through TGA-FTIR-DSC-MCC and Hill Climbing Optimization methods

Pyrolysis technology is one of the most effective thermal treatment methods recycling rigid polyurethane foam (RPUF) waste. To optimize pyrolysis recovery efficiency, quantifying the pyrolysis reaction kinetics and the heat required for the thermal treatment process is critical. This work focuses on establishing a systematic methodology to quantify pyrolysis reaction kinetics and thermodynamics for RPUF waste. RPUF waste with two different densities (RPUFρ100 and RPUFρ45) were investigated using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) under anaerobic atmosphere to measure mass and heat flow information. The obtained data were inversely analyzed using a numerical framework known as ThermaKin2Ds. Pyrolysis reaction mechanisms with four and three consecutive first-order reactions were developed to reproduce the TGA data for RPUFρ100 and RPUFρ45, respectively. The Hill Climbing Optimization Algorithm was employed to adjust the reaction kinetics for an improved agreement between the ThermaKin2Ds-reproduced and experimental data. Based on the heat flow data from DSC tests, the specific heat capacity of each condensed-phase component was determined by using the inverse modeling method. Additionally, the micro-scale combustion calorimeter was used to generate the heat release data that served as the target data for inversely determining the heats of complete combustion, hc, of each pyrolyzate. The established pyrolysis reaction models was further validated by predicting the TGA results collected under different external heating conditions. Subsequently, the generated combustion-inhibiting gases (CO2) and combustion-promoting gases (olefins, alkanes, carboxylic acids, etc.) were characterized through TGA coupled with Fourier-transform infrared spectroscopy (TG-FTIR). This allowed us to elucidate the gas-phase combustion phenomena observed in MCC experiments. This work provides a core set of parameters for optimizing the thermal treatment conditions of RPUF waste.

Investigating supplementary cementitious materials' effects on stabilized aggregate performance, behaviour, and design aspects

Supplementary Cementitious Materials (SCMs) have been widely accepted in the concrete industry due to their varied advantages. However, the same reflects little in the case of Cementitious Stabilized Aggregates (CSA). The present work focuses on the potential and practical application of SCMs in CSA based on laboratory-based growth and performance analysis followed by their design aspects and economic advantages. Fly ash and Crushed Granulated Blast Furnace Steel Slag (GBFS) were chosen at 30% and 50% by weight of cement as partial replacement to cementitious material to prepare a cementitious stabilized mix of aggregates. Mechanical and microstructural properties were then assessed through critical tests like Unconfined Compression Strength (UCS), Flexural Strength (FS), Flexural Modulus (FM) and Thermogravimetric Analysis (TGA) over subsequent curing periods. Results from these tests revealed improved performance on including SCMs in significant proportion when compared to cement mix of aggregates. Power-law relationships proved optimal for comprehending strength and stiffness growth in CSA. Mixes with SCMs exhibited higher growth coefficients and growth rates for UCS, FS and FM. TGA data showed higher bound water loss %, indicating increased hydration for SCMs mixes. Composite pavement design revealed a 5 mm increase in the bituminous layer for cement-fly ash mix, while it remained unchanged for cement and cement-GBFS mix. Economic analysis demonstrated SCM cost savings of 6% to 16% in the CSA layer in mixes with SCMs.

NIR-absorbing TCBD and cyclohexa-2,5-diene-1,4-diylidene-expanded TCBD bridged derivatives of 1,1′-bis(N,N-dimethylaniline)-substituted ferrocene

Symmetrical and unsymmetrical donor-acceptor (D–A) based chromophores were designed and synthesized by the Pd–catalyzed Sonogashira cross–coupling reaction of 1,1′-diiodoferrocene with (4-N,N-dimethylaminophenyl)ethyne followed by [2+2] cycloaddition-retroelectrocyclization reaction with tetracyanoethylene (TCNE) or 7,7,8,8-tetracyanoquinodimethane (TCNQ). Ferrocene was used as a central donor unit and 4-(N,N-dimethylamino)phenyl group as the end-capping donor. Herein, we report the cycloaddition-retrocyclization reaction of TCNE/TCNQ groups on the disubstituted ferrocene containing more than one triple bond to get disubstituted tetracyanobutadiene (TCBD) and cyclohexa-2,5-diene-1,4-diylidene-expanded TCBD products. The effect of the conjugation length and different π–acceptor linkers were investigated by photophysical, redox and computational studies. The redox study reveals multiple oxidation waves corresponding to donor moieties (ferrocene and 4-(N,N-dimethylamino)phenyl group) and reduction waves corresponding to acceptor units (TCBD / cyclohexa-2,5- diene-1,4-diylidene-expanded TCBD). The thermogravimetric analysis data shows that the compounds exhibit high thermal stability. The computational studies reveal HOMO-LUMO gaps consistent with the experimentally obtained data.

The effect of uncertainty in calibration data on burning rate predictions

Comprehensive pyrolysis models describe solid phase reaction rates with respect to the material temperature and the concentrations of components. In theory, this aspect of comprehensive pyrolysis models allows for true predictive capabilities for pyrolysis models and, more generally, fire models. To utilize these capabilities, the reaction kinetics must be defined for the material of interest and there is a lack of publicly available data from which these kinetic parameters may be determined. There is also a lack of guidance for quality and repeatability for thermal analysis experiments, which complicates the use of mean thermal analysis data found in the literature to estimate the thermal degradation kinetics. This study details a numerical investigation on the effect of repeatability of thermogravimetric analysis data on the kinetics calibrated from the data. The uncertainty in the kinetic parameters that corresponded to target repeatability values imposed on synthetic calibration data was determined through a latin hypercube sampling procedure. The generalized polynomial chaos expansions method allowed propagation of the uncertainty of the kinetic parameters through a one-dimensional model of a bench-scale experiment. The relationship between uncertainty in calibration data and uncertainty in bench-scale model predictions was linear.

Liquid phase methanol synthesis by CO2 hydrogenation over Cu-Zn/Z catalysts: Influence of Cd promotion

BackgroundThe current scenario of high CO2 emissions, which is causing global warming and climate change, one of the greatest challenges faced by the global community. One of the most promising ways to recycle CO2 and thus mitigate its emission into the natural environment is the catalytic conversion of CO2 into valuable products such as methanol, hydrocarbons, dimethyl ether (DME), formaldehyde, syngas, alcohols and urea. MethodZeolite supported Cu-Zn bimetallic (Cu-Zn/Z) catalysts were synthesized by co-precipitation method. The synthesized catalysts were doped with different concentration of Cd to investigate the promoting role of Cd. To investigate the physicochemical profile of the calcined Cu-Zn/Z nano-catalysts, various analytical techniques were used. Significant findingsThermal stability of zeolite support was carried out using Thermogravimetric analysis (TGA). TGA data exhibited higher thermal stability of the zeolite support. XRD findings revealed highly dispersed Cd promoted Cu-Zn oxides on the surface of the zeolite support. Field Emission Scanning Electron Microscopy (FESEM) was used to investigate morphology, which indicated the nano size of synthesized catalysts with uniform distribution of metal oxides. Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) detected bulk composition of each metal. BET surface studies revealed the mesoporous nature of Cd promoted Cu-Zn/Z catalysts. X-ray Photoelectron Spectroscopy (XPS) revealed the surface chemistry of Cd promoted Cu-Zn/Z catalysts. Activity data showed the active profile of Cd promoted Cu-Zn/Z catalysts for CO2 hydrogenation to methanol by accelerating the methanol synthesis rate from 73 to 157 g.meth/kg.cat.h. Structure-activity studies identified metal-support interactions and Cu stability as the main factors governing the three-phase methanol synthesis rate from CO2 hydrogenation. The importance of Cd promotion was further demonstrated by the fact that activity profile revealed better performance of the current catalysts with recently reported data in the literature.

Prediction of Thermogravimetric Data in the Thermal Recycling of e-waste Using Machine Learning Techniques: A Data-driven Approach.

The release of bromine-free hydrocarbons and gases is a major challenge faced in the thermal recycling of e-waste due to the corrosive effects of produced HBr. Metal oxides such as Fe2O3 (hematite) are excellent debrominating agents, and they are copyrolyzed along with tetrabromophenol (TBP), a lesser used brominated flame retardant that is a constituent of printed circuit boards in electronic equipment. The pyrolytic (N2) and oxidative (O2) decomposition of TBP with Fe2O3 has been previously investigated with thermogravimetric analysis (TGA) at four different heating rates of 5, 10, 15, and 20 °C/min, and the mass loss data between room temperature and 800 °C were reported. The objective of our paper is to study the effectiveness of machine learning (ML) techniques to reproduce these TGA data so that the use of the instrument can be eliminated to enhance the potential of online monitoring of copyrolysis in e-waste treatment. This will reduce experimental and human errors as well as improve process time significantly. TGA data are both nonlinear and multidimensional, and hence, nonlinear regression techniques such as random forest (RF) and gradient boosting regression (GBR) showed the highest prediction accuracies of 0.999 and lowest prediction errors among all the ML models employed in this work. The large data sets allowed us to explore three different scenarios of model training and validation, where the number of training samples were varied from 10,000 to 40,000 for both TBP and TBP + hematite samples under N2 (pyrolysis) and O2 (combustion) environments. The novelty of our study is that ML techniques have not been employed for the copyrolysis of these compounds, while the significance is the excellent potential of enhanced online monitoring of e-waste treatment and extension to other characterization techniques such as spectroscopy and chromatography. Lastly, e-waste recycling could greatly benefit from ML applications since it has the potential to reduce total and operational costs and improve overall process time and efficiency, thereby encouraging more treatment plants to adopt these techniques, resulting in reducing the increasing environmental footprint of e-waste.

Evaluating thermogravimetric analysis for the measurement of drug loading in mesoporous silica nanoparticles (MSNs)

In this study, a thermogravimetric analysis (TGA) method for measuring the drug loading in mesoporous silica nanoparticles (MSNs) has been developed and evaluated in comparison with the drug loading quantification by high-performance liquid chromatography (HPLC). Indapamide was loaded into two different types of MSNs, namely Mobile Crystalline Material (MCM-41, pore size = 1.2 nm) and Santa Barbara Amorphous (SBA-15, pore size = 4.1 nm). Physical mixtures of the drug and silica gave a linear correlation between the observed and expected drug content for both TGA and HPLC, which were used for calibration purposes. The limit of detection (LOD) for the TGA method obtained from the physical mixture calibration curve was 0.77 % (w/w) and the r2 value was 0.9936, whereas the HPLC had a LOD of 0.06 % (w/w) and an r2 value of 0.9933. The sensitivity of the TGA method was well established using the drug loading studies, as it can detect the low loading of MCM-41 at 2.2 ± 0.21 % (w/w), compared to 5.1 ± 0.12 % (w/w) with the SBA-15. In all samples applied, the multiple comparison analysis showed an insignificant difference between the two methods (p > 0.05). The TGA data presented good evidence for using this technique as a sensitive, cost-effective, and low-variable quantitative analysis in the drug loading determination of the MSNs. TGA is not a selective method of quantification, but optimising the method using the pure and blank samples of MSNs and drug can significantly improve the sensitivity. This work provides a unique approach to apply TGA as a selective and more favourable method to characterise MSNs to do early formulation developments.

Qualitative and Quantitative Investigation of Biochar-Cu0 Composite for Nickel Adsorption.

The current investigation deals with the treatment of water pollution that is caused by the leaching of nickel ions from the metallurgical industry and new-energy batteries. Therefore, an eco-friendly treatment of nickel through the use of a composite of cotton stalk biochar with nanozerovalent copper has been presented in this investigation signifying the impact of zerovalent copper in enhancing the adsorption capacity of biochar for nickel adsorption. Thermogravimetric analysis data showed the adsorbent to be significantly stable in the higher thermal range, whereas transmission electron microscopy analysis confirmed the particles to be 27 nm and also showed the cubic geometry of the particles. A much closer scanning electron microscopy analysis shows the morphology of particles to be cubic in shape. Batch adsorption indicated a positive influence of pH increase on adsorption due to the electrostatic attraction between positive nickel ions and post point of zero charge (pHPZC) negative surface of copper biochar composite (pH > 5.5). A high adsorption rate was observed in the first 60 min, whereas adsorption increased with the increase in temperature from 303 to 318 K. Kinetic modeling confirmed the pseudo-first-order to fit best to the data. The apparent activation energy (11.96 kJ mol-1) is indicative of the chemical nature of the process. The adsorption data fitted well to the Langmuir adsorption model. The negative values of apparent ΔG° and the positive values of apparent ΔH° indicate the spontaneity and endothermicity of the process, respectively, whereas the positive values of apparent ΔS° point toward increased randomness during the process. Postadsorption XPS suggests the adsorption of nickel on the surface of biochar composites in the form of Ni(OH)2 and NiO(OH).

Study of the physico-chemical properties of oligoephiramides based on 4-aminobenzoic acid

This work was carried out to obtain a number of aromatic oligoetheramides and to evaluate the effect of their structure on mesomorphic and thermal properties. Oligoetheramides based on 4-aminobenzoic acid (4-ABA) were synthesized by hightemperature polycondensation. The structure of the obtained compounds was identified by IR spectroscopy, the thermal parameters were determined from the data of thermogravimetric analysis (TGA), the phase transition temperatures were determined by differential scanning calorimetry (DSC), and the manifestation of the optical activity of oligoetheramide solutions was studied by optical polarization microscopy (OPM). It was revealed that the samples dissolve when heated in sulfuric acid, in dimethylformamide (DMF), dimethylacetamide (DMAA) and have limited solubility in dimethylsulfoxide (DMSO). Solutions of oligomers exhibited optical activity at crossed microscope polarizers.

A new multifunctional flame-retardant coating for cotton fabric to enhance smoke suppression, and UV shielding properties

Turmeric powder (TP) is used in the textile industry as a colouring agent, but its impact on the flammability properties of textiles wasn’t investigated. In this work, new coatings containing TP and TP with melamine polyphosphate (MPP) were utilized to enhance the thermal stability, flame retardancy, colour strength (K/S), and UV-protection factor (UPF) of cotton fabric (CF). Flammability tests indicated that TP alone failed to prevent flame spread in the fabric, and it increased the emission of toxic gases, especially CO and CO2. In contrast, the MPP/TP coating was able to put an end to the spread of a flame in CF, and the samples achieved self-extinction. The value of the limiting oxygen index (LOI) of CF was 18.2%, and it enhanced in MPP/TP containing samples to be 37.8%. K/S and UPF values showed that MPP/TP coatings improved the K/S and UPF values of CF to 2.9 and 290, respectively. Additionally, they lowered the toxic gases produced during CF combustion and the maximum specific optical density (Dsmax) of CF. The new coatings improved the char residue production in treated samples at 750 °C compared to CF, according to the thermogravimetric analysis (TGA) data. Untreated and treated samples' mechanical and physical characteristics were measured and compared. Analysis of smoke toxic gases and inspection of char remained following the smoke density test revealed that MPP/TP coating enhanced the flame retardancy of CF in both the condensed and gas phases.

Preparation of multifunctional flame-retardant coating of cotton fabrics for electrical Insulating applications

Cotton fabric (CF) was coated with a new multifunctional flame-retardant system consisting of melamine phosphate (MP) and nickel (II) dimethylglyoxime (NDMG). The new coating was applied to enhance the flame retardancy, antibacterial activity, thermal stability, color strength, UV protection, and electrical properties of CF. The weight percentages of NDMG and MP that led to the maximum improvement in CF properties were identified. According to vertical and horizontal flammability tests, coating the fabric with 29%MP/1%NDMG prevented flame propagation in the samples. Moreover, it increased the limiting oxygen index (LOI) of CF from 17.9% to 36.9%. Thermogravimetric analysis (TGA) data presented that the MP/NDMG coating enhanced the char residue at 750°C. Antimicrobial investigations indicated that the coating 29%MP/1%NDMG reduced the growth of S. aureus and E. coli bacteria. UV shielding and color strength (K/S) results revealed that coated fabrics had excellent UV protection (UPF > 175) and enhanced K/S values. The tensile strength of CF was slightly decreased after the coating process. The dielectric constant (ε`), the dielectric loss (ε``), and AC electrical resistivity ([Formula: see text]) with frequency (10-106 Hz) were also investigated. The electrical resistivity increased significantly after adding MP and NDMG to the CFs. The coated sample (23%MP/7%NDMG) showed the best dielectric properties, with a low dielectric constant of 2.6 and [Formula: see text] of 1.40E+10 Ω.cm at 1000 Hz.

A review on biomass thermal-oxidative decomposition data and machine learning prediction of thermal analysis

Thermochemical conversion is the most economical approach to recovering energy and alternative fuels from biomass feedstock. This work first reviews the literature data on thermal-oxidative decomposition for common biomass types and forms a database of 18 parameters, including element, proximate, and thermogravimetric analysis (TGA). Then, an Artificial Neural Network (ANN) model is developed for the prediction of TGA data. Pearson correlation coefficient analysis reveals that the influence of environment heating rate on biomass thermal decomposition is larger than that of fuel properties. By inputting biomass elemental/proximate analysis and heating rate, the ANN model successfully predicts 8 key TGA parameters, namely, pyrolysis-onset temperature, peak pyrolysis temperature, oxidation-dominant temperature, peak oxidation temperature, oxidation-end temperature, peak pyrolysis rate, oxidation-dominant rate, and peak oxidation rate, with R2 values greater than 0.98. A better performance can be achieved when all ten input features are considered. Final, an open-access online software, Intelligent Fuel Thermal Analysis (IFTA), is developed to predict thermal-oxidative decomposition across a wide range of heating rates and biomass types. This work provides a better understanding of biomass thermal-oxidative decomposition dynamics and a shortcut to obtain key parameters of biomass degradation without TGA tests.

Establishment of patterns in the thermal modification of dry pine wood

One of the methods of ensuring the durability of dry wood during operation is its thermal modification, which inhibits the life processes of the fungus of the Ceratostomaceae family and leads to a change in its structure and properties. Therefore, the object of research was thermally modified dry pine wood affected by a fungus of the Ceratostomaceae family. Physicochemical studies of changes in the structure of thermally modified dry pine wood showed that the samples have absorption spectra that are characterized by fluctuations of the glucopyranose ring of cellulose and are an indicator of the beginning of destructive processes. At the same time, the data of thermogravimetric analysis show the processes of water loss and decomposition of hemicellulose, cellulose, and lignin, and burning of coke residue. Bending and compressive strength of thermally modified dry pine wood shows that as the wood dries, the strength limit decreases depending on the degree of fungus damage. Namely, with an area of biological damage within 10 %, the strength limit is reduced by more than 1.2 times when modified at 200 °С/3 hours, by more than 1.9 times at 200 °С/6 hours. With an increase in the degree of fungal damage to 30÷50 %, the strength limit decreases by more than 1.6 times when modified at 200 °С/3 hours, by more than 2.1 at 200 °С/6 hours. And when affected by a fungus in the range of 80÷100 %, the wood becomes softer, more plastic, while the bending strength is reduced by 1.7 times, and the compressive strength by 1.16 times. Thermal modification of dry pine wood at 200 °С for 3 hours reduces the level of water absorption by more than 1.5 times, and for 6 hours ‒ by more than 1.7 times. The practical importance is that the results of determining changes in the structure and properties of thermally modified dry pine wood make it possible to establish the scope and conditions of its application

Identification and quantification of soil water components in kaolin by thermogravimetric and kinetic analysis

Different types of soil water, such as bound water and capillary water, have distinct effects on the physicochemical and engineering properties of soils, particularly unsaturated clayey soils. Therefore, it is crucial to develop an accurate and physically meaningful experimental method for identifying and quantifying these components. This study pioneers the use of a multi-step kinetic model to identify and quantify different soil water components across a wide range of relative humidity (RH) using thermogravimetric analysis (TGA) data. To validate the determined kinetic parameters (i.e., activation energy, preexponential factor, and reaction model) and the identification and quantification results of soil water components, TGA with multiple heating rates, nitrogen adsorption method, cation exchange capacity measurement, and nuclear magnetic resonance (NMR) were performed on kaolin samples equilibrated under various RH conditions. These experimental results cross-validate the superior performance of the kinetic model in determining soil water components and predicting the thermal desorption behaviors of soil water. Based on the cross-validation results, the soil water components obtained from the kinetic analysis are further identified as tightly-bound, loosely-bound, and capillary water, which exhibit variations consistent with empirical soil water isotherm models. The T2 cutoff value between bound and capillary water is determined to be 1.79 ms based on TGA and NMR results. The determined thermal kinetic parameters of different soil water components can exhibit their distinct retention mechanisms. The method and results in this study provide a new perspective on identifying different soil water components, as well as understanding the mechanism of soil-water interactions in unsaturated soils.

Kinetics of the Water Release of Hygroscopic Acrylamide Gel Embedded in Calcium Chloride by Thermogravimetric Analysis

Poly (acrylamide) gel was synthesized by radical polymerization of acrylamide and N, N'-methylene-bisacrylamide in the presence of benzoyl peroxide and carbon nanotubes. The dry product was saturated with calcium chloride and prepared for water absorption and desorption. The kinetics of water desorption of poly (acrylamide) gel embedded with hygroscopic calcium chloride (DHG), was studied from thermograms data of thermogravimetric analysis (TGA). DHG captures vapor from the environment and releases it as fresh water; it can be used as the condenser to build atmospheric water generators (AWGs) to alleviate the freshwater stress rusting from innovative activities such as industrial, agricultural, rural, and defense endeavors. The kinetics parameters of the synthesized DHG showed that it absorbed environmental vapor at room temperature and released water below its boiling point (40 to 90 °C), temperatures achievable under sunlight via the photothermal effect.

Bio-green synthesis of calcium acetate from oyster shell waste at low cost and reducing the emission of greenhouse gases

Biological wastes obtained from food, oyster shells, were recycled to calcium carbonate and then used as bio-green raw material to replace limestone/carbonate stone for calcium acetate (Ca(CH3COO)2·H2O) production. The conditions (ambient temperature occurred in an exothermic reaction, drying time, yield, and solubility) of the reaction between the bio-green CaCO3 and three different acetic (CH3COOH) concentrations (8, 10, and 12 M) were investigated. The product's maximum yield (93%) with a shorter drying time (18 h) was obtained from the reaction between the bio-green CaCO3 with 12 M acetic acid revealing a lower cost. The chemical compositions without any toxic metal impurity revealed by the X-ray fluorescence technique would be useful to suggest use in the specific application. The X-ray diffraction, Fourier Transform Infrared, and Thermogravimetric analysis data of Ca(CH3COO)2·H2O prepared by the bio-green CaCO3 obtained from oyster shell wastes in this work and those in previous works used other calcium sources were consistent. The morphologies with different sizes of the obtained Ca(CH3COO)2·H2O depend on the CH3COOH concentrations reported in this work and were different from those reported in previous works because of different calcium sources. According to the observation, it can be concluded that the low-cost and bio-green technique without the environmental effects was successfully applied to produce cheap Ca(CH3COO)2·H2O and reduce greenhouse gas emissions, which can be used in the specific industry.

Oxidation Kinetics Analysis of Crude Oils with Different Viscosities

In order to compare the oxidation kinetics parameters of crude oils with different properties in the process of crude oil oxidation, six different crude oil samples were selected to analyze the oxidation characteristics of crude oils with different properties. In order to study the oxidation of crude oil, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) synchronous analyzer were used for crude oil in the oxygen environment between 25 °C and 900 °C at a heating rate of 20 °C/min. The experimental results were based on crude oil oxidation using TGA and DTG experimental data to evaluate the oxidation mechanism of different crude oils, so as to better understand the situation in the oxidation reaction process. At the same time, the oxidation stage of crude oil was divided according to DSC data. Arrhenius method was used to analyze the oxidation kinetic parameters of crude oils with different properties, and the activation energies and pre-exponential factors of different crude oils were calculated. The experimental results show that the oxidation stage of crude oil can be divided into three stages: low-temperature oxidation, fuel deposition, and high-temperature oxidation. The low-temperature oxidation reaction begins at 280 °C, and the high-temperature oxidation reaction occurs at 400 °C. The low-temperature oxidation activation energy of an oil sample is 39.73–77.74 kJ/mol. The activation energy of the high-temperature oxidation is in the range of 106.27–264.47 kJ/mol. The activation energy of crude oil in the low-temperature oxidation stage increases with the increase of crude oil viscosity and decreases with the increase of crude oil viscosity in the high-temperature oxidation stage. Therefore, during the high-temperature oxidation stage, high-viscosity crude oil is more prone to reactions.

Flame-retardant and anti-corrosion behaviour of cardanol-based polybenzoxazine composites

A new monomer of bi-functional benzoxazine was synthesised using cardanol (C) and p-phenylenediamine (ppda) under suitable experimental conditions. The curing behaviour of the cardanol-based 1,4-bis(7-pentadecyl-2H-benzo[1,3]oxazin-3(4H)-yl)benzene (C-ppda) benzoxazine monomer was studied by differential scanning calorimetry analysis, and the polymerisation temperature (T p) of C-ppda benzoxazine was found to be 237°C. Further, the benzoxazine monomer was reinforced with varying weight percentages (5, 10 and 15 wt%) of bio-ash derived from Aerva lanata (AL-ash) to obtain hybrid composites. Thermogravimetric analysis data indicate that AL-ash-reinforced benzoxazine composites possess excellent thermal stability and a flame-retardant behaviour. The morphology of AL-ash- and cardanol-based benzoxazine composites was analysed using field emission scanning electron microscopy (FESEM). The FESEM results indicate homogeneous distribution of AL-ash in the composites. Energy-dispersive X-ray spectroscopy analysis was used to determine the elemental composition of the AL-ash used for the preparation of composites. The value of the water contact angle of poly(C-ppda) was found to be 148°. Data obtained from corrosion studies indicate that the mild steel specimen coated with a benzoxazine matrix and the specimen coated with bio-ash-reinforced benzoxazine composites exhibit an excellent resistance against corrosion. The bio-ash-reinforced composites of cardanol-based benzoxazine can be used in the form of sealants, encapsulants, adhesives, coatings and matrices in microelectronics and automobile applications under high thermal and moist environmental conditions.