Thermogravimetric Differential Thermal Analysis Research Articles

Development and characterization of novel CS-ZnO-Alg polyelectrolyte complex for enhanced removal of Cd(II), Cu(II), and Ni(II) from simulated paint industrial wastewater

In this study, we developed and characterized a novel chitosan-alginate-based polyelectrolyte complex impregnated with zinc oxide nanoparticles (CS-ZnO-Alg PEC) for the enhanced removal of Cd(II), Cu(II), and Ni(II) from simulated paint industrial wastewater. The prepared PEC was characterized by X-ray Diffraction (XRD), Fourier-Transform Infrared (FTIR) Spectroscopy, Scanning Electron Microscopy/Energy Dispersive Spectroscopy (SEM/EDS), X-ray Photoelectron Spectroscopy (XPS), Brunauer-Emmett-Teller (BET), and Thermogravimetric analysis/Differential Thermal Analysis (TGA/DTA). The equilibrium data for said metal ions was best appropriated by Freundlich isotherm with maximum adsorption capacity of 217.72 mg/g for Cd(II), 130.41 mg/g Cu(II), and 159.06 mg/g for Ni(II), illustrating the multilayer adsorption of metal ions on the heterogeneous surface sites of the adsorbent. The kinetics of all three metal ions adsorption process onto discussed PEC was consistent with pseudo-second-order model. The thermodynamics results illustrate exothermic and spontaneous processes for Cd(II) (ΔH° = −3.57 KJ/mol, ΔS° = 0.009 KJ/mol*K, ΔG° = −6.42 to −6.61 KJ/mol) and Cu(II) (ΔH° = −3.32 KJ/mol, ΔS° = 0.006 KJ/mol*K, ΔG° = −5.25 to −5.37 KJ/mol), and spontaneous but less favorable adsorption for Ni(II) (ΔH° = −0.82 KJ/mol, ΔS° = −0.001 KJ/mol*K, ΔG° = −0.39 to −0.36 KJ/mol). Notably, the PEC could be easily recycled and regenerated, maintaining adsorption efficiency after five cycles. Overall, the CS-ZnO-Alg PEC, due to its amphoteric nature, high adsorption efficiency, cost-effectiveness, excellent recyclability, and biodegradability, could be a promising adsorbent for paint industrial wastewater.

Effects of mixing water and environmental pH value on the properties of sulfoaluminate cement-based ultra-high water materials

In order to grasp the influence of the pH value of mixing water and environmental water on the properties of ultra-high water materials, this article separately carried out the influence of different pH values of mixing water on the properties of ultra-high water materials and the conservation of high-water materials in water environments with different pH values. Using test methods such as loss of flow time, compressive strength, Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD), Thermogravimetric-Differential Thermal Analysis (TG–DTA), to conduct regular exploration and mechanism analysis. The study found that with the continuous increase of the pH value of the mixing water, the loss of flow time of the ultra-high water material gradually decreased, and the compressive strength of the samples at the same age continued to increase. A lower pH value will affect the compressive strength of the consolidated body of the ultra-high water material, but when the pH = 13 in the reaction solution, the compressive strength of the consolidated body will no longer increase and begin to produce a weakening effect. The pH of the construction water for ultra-high water materials is recommended to be 4–13. At the same time, it was found that under the conservation of an acidic environment, the consolidated body was severely eroded and the strength loss was large. The acid–base environment of the goaf suitable for filling with the ultra-high water material should be between pH = 7–10 to ensure that the filling body is not weakened by erosion.

Direct oxidation of alcohols to carboxylic acids using simple and economical Pd@Glu-HTC catalyst: Practical and scalable approach towards biomass based value added chemicals

Sustainable catalytic transformation of bio-based alcohols to high value-added fine chemicals is an important topic of research. This work described preparation of simple and economical Pd@Glu-HTC catalyst from biomass derived low cost d-glucose. Hydrothermal carbonization of glucose was carried out in first step to synthesize Glu-HTC support in a simpler, greener, economical and efficient manner followed by incorporation of palladium metal on surface of the catalyst in second step. The catalyst was characterized using techniques such as Fourier Transform Infrared Spectroscopy (FT-IR), Solid-state Cross-Polarization Magic Angle Spinning Carbon-13 (13C CPMAS), Energy-dispersive X-ray spectroscopy (EDAX), Powder X-ray diffraction (P-XRD), X-ray photoelectron spectroscopy (XPS), Thermogravimetric/Differential Thermal Analyzer (TG-DTA), Field emission scanning electron microscopy (FE-SEM) and High-resolution transmission electron microscopy (HR-TEM). The catalyst was evaluated for direct oxidation of alcohols to yield carboxylic acids and exhibited very good catalytic activity for wider substrate scope. Oxidation of alcohols was carried out using milder base, molecular oxygen and water as a solvent to achieve 92–99 % excellent yields. The practical utility of current strategy was also studied for gram scale synthesis of bio-based value added industrially important chemicals such as furoic acid (flavouring agent and preservative in industry), 2, 5-furan-dicarboxylic acid (monomer to 100 % fossil-free, recyclable polymer polyethylene furanoate (PEF), tetrahydro-2-furoic acid (production of many drugs) and vanillin (important product of flavor and fragrance industry). Pd@Glu-HTC catalyst was found to be reusable for four recycles and the catalytic performance was retained without any loss in its activity after four cycles.

Optimization of Water Hyacinth Stem-Based Oxygen-Functionalized Activated Carbon for Enhanced Supercapacitors.

In the current world, storing and converting energy without affecting the natural ecosystem are considered a sustainable and efficient green energy source production technology. Especially, using low-cost, environmentally friendly, and high-cycle stability activated carbon (AC) from the water hyacinth (Eichhornia crassipes) waste material for charge storage application is the current attractive strategy for renewable energy generation. In this study, preparation of AC from water hyacinth using a mixed chemical activation agent followed by activation time was optimized by the I-optimal coordinate exchange design model based on a 3-factor/3-level strategy under nine experimental runs. The optimum conditions to prepare AC were found to be potassium hydroxide (≈17 g) and potassium carbonate (≈11 g), and the carbonization time was approximately 1 h. Under these augmented conditions, the maximum specific capacitance suggested by the designed model was found to be ≈75.2 F/g. The regression coefficient (R 2 = 0.9979), adjusted (R 2 = 0.9917), predicted (R 2 = 0.8706), adequate precision (39.2795), and p-values (0.0062) proved the good correlation between actual and predicted values. The physicochemical and electrochemical properties of the final optimized AC were characterized by thermogravimetric/differential thermal analysis (TGA/DTA), X-ray diffractometry (XRD), Fourier transform infrared (FTIR), Brunauer-Emmett-Teller (BET), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), selected area electron diffraction (SAED), and potentiostat (CV and EIS) instruments. Finally, the optimized AC electrode after 100 cycles at a current density of 2 A g-1 retains an efficiency of 71.57%, indicating the good stability and sustainability of this material.

Synthesis of Low-Silicon X-Type Zeolite from Lithium Slag and Its Fast Exchange Performance of Calcium and Magnesium Ions.

Without the addition of silicon and aluminum sources, a pure-phase KNaLSX zeolite was successfully synthesized from the residue (lithium slag), which was produced from spodumene in the production process of lithium carbonate. The KNaLSX samples were characterized by an X-ray Diffractometer (XRD), Scanning Electron Microscope (SEM), X-ray Fluorescence Spectrometer (XRF), Thermogravimetric Differential Thermal Analysis (TG-DTA), Fourier Transform Infrared Spectrometer (FT-IR), and N2 adsorption measurement. The ion exchange capacity and the ion exchange rate of calcium and magnesium ions were measured as used for a detergent builder, and the results were compared with the standard zeolites (KNaLSX and 4A). The experimental results show that the pure-phase KNaLSX synthSynthesis and characterization of co-crystalline zeolite composite of LSX/esized from lithium slag has a SiO2/Al2O3 ratio of 2.01 with a grain size of 3~4 μm, which is close to the commercial KNaLSX sample of a SiO2/Al2O3 ratio of 2.0. The BET-specific surface area of KNaLSX is 715 m2/g, which is larger than the low-silicon X-type zeolite (LSX) synthesized from waste residue reported in the literature. The ion exchange rate constant of calcium and magnesium ions in KNaLSX is 5 times and 3 times that of 4A zeolite, respectively. KNaLSX also has a high ion exchange capacity for magnesium ion of 191 mgMgCO3/g, which is 2 times than that of 4A zeolite, and a high ion exchange capacity for calcium ion of 302 mgCaCO3/g, which meets the first-grade standard of zeolite for detergent builders in China. The work provides the basis for high-value resource utilization of lithium slag and the development of a detergent builder for rapid washing.

Synthesis of 3,4-dihydropyrimidines and octahydroquinazolinones by SBA-15 supported schiff-base iron (III) complex as durable and reusable catalyst under ultrasound irradiation

Biginelli-type heterocyclic compounds are particularly important due to their several chemical reactivities and various range of pharmacological activity. Therefore Biginelli reaction has witnessed several modification and numerous investigations are continuing in this field to develop more effective and efficient methodologies. In this research, Iron (III) schiff base immobilized SBA-15 has been prepared as a valuable, efficient, and recoverable catalyst for the Biginelli reaction. The morphology of the prepared catalyst was identified by spectroscopic characterization techniques and structural microscopic analysis including Fourier transform infrared (FT-IR) patterns, X-ray diffraction (XRD) by powder crystal method, Energy-dispersive X-ray spectroscopy (EDS) study, Thermogravimetric-Differential thermal analysis (TGA-DTA), Transmission electron microscopy (TEM) and Field emission scanning electron microscopy (FE-SEM) images. Biginelli compounds containing 3,4-dihydropyrimidines and octahydroquinazolinones were conveniently synthesized by this catalyzed protocol from the cycloaddition of aromatic aldehydes with the 1,3-dicarbonyl substrates and urea via ultrasonic waves. The several advantages of the presented approach are high yields and easy isolation of products, shorter reaction times, and milder conditions, structural stability and reusable catalyst. The combination of heterogeneous catalyst and ultrasonic radiation can make catalytic reactions more efficient than traditional ways attractive for academic researchers and application scholars in the industry.

Fabrication of pesticide/LDH-LAP composite assisted by zwitterionic surfactant

Using zinc-aluminum layered double hydroxides-laponite (LDH-LAP) complex as matrix, with the assistance of zwitterionic surfactants of hexadecyl dimethyl sulfobetaine (SB) and dodecyl dimethyl carboxyl betaine (DCB), the pesticides beta-cypermethrin (BCT) and imidacloprid (IMP) were inserted into the LDH-LAP to obtain BCT/SB-LDH-LAP, BCT/DCB-LDH-LAP, BCT/SB-DCB-LDH-LAP and IMP/DCB-LDH-LAP composites, respectively. Powder X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR), thermogravimetric/differential thermal analysis (TGA/DTA) and scanning electron microscope (SEM) were used to characterize the structural properties of composites. BCT/SB-LDH-LAP, BCT/DCB-LDH-LAP, BCT/SB-DCB-LDH-LAP and IMP/DCB-LDH-LAP had larger interlayer distances of 4.29, 4.33, 4.33 and 4.61 nm, which were bigger than those of SB-LDH-LAP (3.87 nm), DCB-LDH-LAP (3.83 nm) and LDH-LAP (1.65 nm). The FT-IR and TGA/DTA results further confirmed the existence of SB, DCB, BCT and IMP into LDH-LAP. The pesticide releases were investigated and analyzed in pH 5.0 and 6.8 buffer solutions. The release behaviors can be fitted by pseudo second-order and parabolic diffusion models. The composites based on LDH-LAP could be suggested to potential application for controlled-release of the pesticide.

Green synthesis of silver oxide nanoparticles using Trigonella foenum-graecum leaf extract and their characterization

The unique physical and chemical properties of silver nanoparticles (Ag NPs) of different sizes and shapes made their synthesis expedient. The most important method of NPs synthesis is the chemical process. However, the disadvantages of this method are the need for specific conditions such as high temperatures, to ensure formation and stability of NPs, as well as use of heavy aromatic solvents. Biosynthesis of NPs is considered advantageous over the traditional chemical approach. In this paper, the first report of the synthesis of silver oxide (AgO) NPs using Trigonella foenum-graecum leaf extract as a reducing agent is presented. The NPs were characterized by X-ray diffraction (XRD), thermogravimetric analysis/differential thermal analysis (TA/DTA), UV, photolumines-cence, SEM, EDX and high resolution transmission electron microscopy (HRTEM). The XRD confirmed the formation of high-purity AgO fine crystals. The average crystal size ranged from 27 to 32 nm as was revealed by HRTEM. From the Tauc plot, the optical band gap of the AgO crystals of 3.3 eV was determined. Thermal analysis provided the optimum temperature for calcination of the AgO NPs to be 400 °C.

Synthesis of carbazole-based Schiff base and fluorescence turn on sensor sensitive to Cr3+ ion: Oxidative and electrochemical polymerization and investigation of electrochromic properties

In this study, a Schiff base monomer (ECBA) was initially synthesized from condensation reaction of 3-amino 9-ethyl carbazole (AEC) with 2,4-dihydroxy benzaldehyde (DHBA). Then, its poly(ECBA-1) polymer was synthesized via oxidative polycondensation in methanol/THF (v/v:4/1) medium by NaOCl oxidant. The structures of the obtained monomer and poly(ECBA-1) were confirmed by 1H NMR, 13C NMR and FT-IR. The optical and electrochemical properties of compounds were examined by UV–Vis, fluorescence spectroscopy and cyclic voltammetry (CV) measurements, respectively. The Highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO) energy levels and electrochemical (E’g) and optical band gap (Eg) values were determined for monomer and polymer compounds by cyclic voltammetry and UV–Vis spectrophotometry. Thermal stabilities of the monomer and poly(ECBA-1) were determined from thermogravimetric-differential thermal analysis (TG-DTA) measurements. The molecular weight distribution and Tg temperature of the poly(ECBA-1) were determined by gel permeation chromatography (GPC) and differential scanning calorimetry (DSC) measurements, respectively. The surface morphologies of the synthesized polymers and copolymer were investigated by scanning electron microscopy (SEM). By fluorescence titration, ECBA was found to be selective towards Cr3+ ion among Ag+, K+, Mn2+, Hg2+, Co2+, Ca2+, Ni2+, Cu2+, Zn2+, Pb2+, Cd2+, Fe3+, Cr3+, Cr+6 ions. The selectivity of Cr3+ion was confirmed by the absence of interference from other competitive cationic species. The limit of detection (LOD) and binding constant (Ka) values for the fluorescent probe were calculated as 6.07 x 10-7 M and 1.25 x 104 M−1, respectively. In addition, homopolymer and copolymer synthesis was carried out on Pet ITO selected as working electrode via electropolymerization method by the synthesized ECBA monomer. Homopolymer synthesis was carried out by Cyclic Voltammetry (CV) method and copolymer synthesis was carried out by batch electrolysis method using EDOT with ECBA monomer. Spectroelectrochemical measurements were taken to investigate the electrochromic properties of the prepared homopolymer poly(ECBA-2) and copolymer (Poly(ECBA-co-EDOT)). The copolymer was found to have a more stable structure than the homopolymer.

Structural, optical, and dielectric properties of aminated PMMA/GO polymer nanocomposite for storage device applications

A series of aminated PMMA/GO polymer nanocomposite (PNG) were synthesized by solution mixing in two step process. The synthesized PNG samples were analysed using X-ray diffraction (XRD), Fourier transform infrared (FTIR), Scanning Electron Microscope (SEM), energy dispersive X-ray analysis (EDAX), Thermo-gravimetric, differential thermal analysis (TG-DTA), UV–Visible spectroscopy (UV–Vis) and impedance spectroscopy. The X-ray diffraction (XRD) data indicated the existence of crystalline nature in PMMA and the reduction of graphene oxide (GO) which is also confirmed by TGA and DTA results. The interaction between graphene oxide nanoparticles and the functionalized polymer matrix has been validated using FTIR investigations. The SEM and EDAX measurements demonstrated the homogeneous dispersion of graphene oxide (GO) over the surface of the produced samples. The UV–Vis spectroscopy analysis revealed that the optical energy gap values of nano composites decrease as the amount of graphene oxide nanoparticles increases. All samples exhibited higher relative permittivity at low frequencies which is a key factor for high energy density. As the concentration of GO increases, the maximum peak of dielectric loss tangent also shifted to higher frequency due to increase in interfaces. The β relaxation is dominant in non-polar PMMA due to the functionalisation and dispersion of GO. The AC conductivity values increased with increase in concentration of GO. The single semicircle in plot from impedance spectroscopy and the drop in bulk resistance values of PNG samples made them as a good material for energy storage devices like supercapacitors.

The performance of iron-silicate-based biochar as a sorbent material towards 133Ba retention from radioactive liquid waste

Abstract The application of Phalaris seed peel (PSP) for the production of biochar involves the pyrolysis process in an N2 environment, resulting in the creation of a cost-effective sorbent. Two distinct modifications were conducted on the existing biochar (BC), employing just silicate (BC/SiO2) and in combination with iron-silicate (BC/SiO2/Fe). Several analytical methods were used to look at the modified biochar’s physical and chemical properties. These included scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis-differential thermal analysis (TGA-DTA), and surface area analysis. Based on the initial investigations, it has been revealed that the use of silica and iron as the second modification is a more suitable approach for effectively retaining 133Ba from liquid radioactive waste streams. The investigation of sorption kinetics and isotherms was conducted to enhance our understanding of the process. The Langmuir isotherm model demonstrates the most optimal correlation for sorption, yielding a maximum sorption capacity (Q max) of 31 mg/g. Furthermore, an evaluation was performed on the BC/SiO2/Fe sorbent material by subjecting it to a mixture of simulated radioactive liquid waste, which included 133Ba, 60Co, and 137Cs.The experimental results indicate that BC/SiO2/Fe exhibits a comparatively higher sorption capacity for 133Ba when compared to 60Co and 137Cs as competing ions.

Thermal decomposition study of 4-methyloxybenzyl-glycoside by TG/DTA and on-line pyrolysis-photoionization mass spectrometry

A flavor precursor of 4-methyloxybenzyl-2, 3, 4, 6-tetra-O-acetyl-β-d-glucopyranoside (MBGL) was synthesized via a modified Koenigs–Knorr reaction. The thermal decomposition behaviour and pyrolysis intermediate products of the glycoside were studied by simultaneous thermogravimetric/differential thermal analysis (TG/DTA) and synchrotron vacuum ultraviolet (VUV) photoionization mass spectrometry (PIMS). TG/DTA results showed that the largest mass loss rate appeared at a Tp of 246.7 °C. PIMS was used to identify the pyrolysis products of MBGL at 300 °C, 500 °C and 700 °C, respectively. The experimental apparatus had some advantages in real-time analysis and fewer secondary reactions. Some important pyrolysis intermediates, such as the ions of the 4-methyloxybenzyl group at m/z 121 and the glycone moiety at m/z 347, were detected by PIMS. The results indicate that the MBGL was probably showed a different pyrolysis way compared with the other glycosides. This work reports a useful application of synchrotron VUV PIMS in a thermal decomposition study of glycoside flavor precursors.

Experimental Study on the Strength and Microstructure of Red Mud-Based Silty Sand Modified with Lime–Fly Ash

This study aimed to assess the viability of utilizing lime–fly ash (LF) and red mud (RM) in the modification of silty soil (LF-RMS) for subgrade filling. The primary objective of this research was to analyze the mechanical characteristics and examine the curing mechanisms associated with said modified materials. Different curing times were utilized in the analysis of mechanical properties (e.g., via unconfined compression testing), microstructure (via scanning electron microscopy, X-ray diffraction, and thermogravimetric-differential thermal analysis), and environmental indices (via assessment of corrosivity, heavy metal concentration, and radioactivity) with various dosages of red mud (DRM) and Lime–fly ash (DLF). Analyses of the curing mechanisms, failure modes, microstructures, and degrees of environmental impact associated with LF-RMS were also undertaken. The tests indicated that the unconfined compressive strength (UCS) exhibited an initial increase followed by a decrease as the DRM and DLF levels increased. Additionally, the strength of LF-RMS increased with an increase in curing time. It is worth noting that the specimen composed of 20% LF and 23% RM (D20%LF+23%RM) demonstrated a maximum UCS value of 4.72 MPa after 90 days of curing, which indicates that it has the strongest ability to resist deformation. The strength of the specimen cured for 90 days was 1.4 times higher than that of the specimen cured for 7 days (1.97 MPa). Furthermore, the toxic concentration and radionuclide index of LF-RMS were significantly reduced compared to those of pure RM. The overall concentration of heavy metals in the D20%LF+23%RM specimen decreased by more than 60% after curing for 28 days. The internal irradiation index and the external irradiation index decreased by 1.63 and 1.69, respectively. The hydration products in LF-RMS play a key role in the solidification of heavy metals, and the alkaline environment provided by RM also contributes to the precipitation and replacement of heavy metals. In this study, red mud, fly ash and lime were used to modify silty soil. The central tenets of sustainable development may be achieved through the reuse of RM as a road filler.

Deprotection of the BOC Groups in Poly(2-(tert‑butoxycarbonyloxy)ethyl methacrylate) controlled by the incorporation of polymerizable thermally latent acids

Poly((2‑tert-butoxycarbonyloxy)ethyl methacrylate) (PBHEMA) is converted to poly(2-hydroxyethyl methacrylate) (PHEMA) with the release of isobutene and CO2 by heating and this reaction is accelerated by an acid. The thermally latent acid catalysts (TLA) are useful for the control of a working temperature for the deprotection of the tert‑butoxycarbonyl (BOC) groups included in PBHEMA. In this study, styrene- and methacrylate-type sulfonic esters were synthesized and copolymerized with BHEMA in order to investigate the effect of the TLAs incorporated into the polymer chains. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) were carried out for the copolymers of BHEMA with the polymerizable TLAs in order to discuss the deprotection features of the BOC group in comparison with the results for the systems of PBHEMA blended with the low-molecular-weight TLAs.

Study of biphasic calcium phosphate (BCP) ceramics of tilapia fish bones by age

Biphasic calcium phosphate (BCP), consisting of bioceramics such as HAp + β-TCP and Ca10(PO4)6(OH)2 + Ca3(PO4)2, is a popular choice for optimizing performance due to its superior biological reabsorption and osseointegration. In this study, BCP was produced by calcining the bones of tilapia fish (Oreochromis niloticus) reared in net cages and slaughtered at an age ranging from 15 to 420 days. The bones were cleaned and dried, calcined at 900 °C for 8 h, and then subjected to high-energy grinding for 3 h to produce BCP powders. After the calcination process, the crystalline phase’s hydroxyapatite (HAp) and/or beta-tricalcium phosphate (β-TCP) were present in the composition of the bioceramic. The age-dependent variation in phase composition was confirmed by complementary vibrational spectroscopy techniques, revealing characteristic peaks and bands of the bioceramic. This variation was marked by an increase in HAp phase and a decrease in β-TCP phase. Thermogravimetric Analysis (TGA) and Differential Thermal Analysis (DTA) from 25 to 1400 °C showed the characteristic mass losses of the material, with a greater loss observed for younger fish, indicating the complete removal of organic components at temperatures above 600 °C. Comparison of the results obtained by X-Ray Diffraction (XRD) and Rietveld refinement with Raman spectroscopy showed excellent agreement. These results showed that with temperature and environment control and adequate fish feeding, it is possible to achieve the desired amounts of each phase by choosing the ideal age of the fish. This bioceramic enables precise measurement of HAp and β-TCP concentrations and Ca/P molar ratio, suitable for medical orthopedics and dentistry.

Spectral, crystal structure of novel Pyran-2-one Zwitterion Schiff derivative: Thermal, Physicochemical, DFT/HSA-interactions, enol↔imine tautomerization and anticancer activity

A novel Schiff base (SB) derivative, (E)-3-(1-((2,6-diisopropylphenyl)-imino)-ethyl)-4‑hydroxy-6-methyl-2H-pyran-2-one, was synthesized in a high yield through the direct condensation of 2,6-diisopropylaniline with 3-acetyl-4‑hydroxy-6-methyl-2H-pyran-2-one in ethanol under reflux conditions. The synthesized ligand was identified using different elemental analysis (CHN-EA) and spectroscopic techniques (2D-nuclear magnetic resonance (1H- & 13C- NMR), Fourier transform infrared (FT-IR) and mass (MS) spectroscopies), and their structural analysis was performed by single crystal X-ray diffraction (XRD). In addition, the thermogravimetric behavior of the ligand was evaluated using thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The DFT calculations on the gaseous state and in chloroform as solvent using B3LYP-D3/6–311++G(2d,p) and the HSA calculations were performed to examine the stability of the tautomeric forms of the ligand and to understand its Zwitterionic behaviors. The results showed that the ligand exhibits a zwitterionic form stabilized by an intramolecular single proton transfer process between the enol and imine tautomerism. The enol↔imine tautomerization was determined by XRD and computed by DFT/HSA calculations, which proved the stabilization of the [N+−−H⋯O−−] zwitterionic form via S6 intra-H-bond. In addition, the Colorimetric [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed that the ligand exhibits high activity against cancer cells, specifically HeLa cells, at low concentrations.

Investigation on structural, optical, thermal, and dielectric properties of cellulose propionate/styrene-maleic anhydride copolymer/molybdenum nanocomposite prepared by pulsed laser ablation

Polymer nanocomposite films of cellulose propionate/styrene-maleic anhydride copolymer/molybdenum (CP/SMAC/Mo) were fabricated by pulsed laser ablation of Mo in the polymer solution for 10, 20, and 30 min. The films were then characterized by various analytical methods. X-ray diffraction (XRD) revealed that the addition of Mo to CP/SMAC removed the crystalline peaks of Mo without changing the amorphous nature of the copolymer. According to the scanning electron microscopy (SEM) and atomic force microscopy (AFM) patterns, Mo atoms were trapped in the amorphous polymer stacks. The energy-dispersive X-ray (EDX) spectrum features C, O, and Mo. FTIR confirmed the embedding of Mo in the polymers. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) were carried out on the samples. The pristine polymer film exhibited a band gap energy of 2.9 eV, which decreased to 2.05 eV because of the loading of the Mo nanoparticles. The intensity of the photoluminescence (PL) peak of the films increases with ablation time such that the absorption intensity of the film at a λmax of 426 nm increases by trifold during the 30 min of irradiation, which is consequently due to the increased amount of Mo in the nanostructure. The incorporation of Mo in the polymer matrix enhances the dielectric constant (ε') (6.28–18.13) and ac conductivity (σac) (3.19 × 10−5–1.12 × 10−4 S/cm) of the polymer with negligible dielectric loss. The results suggest possible technological utilization of these materials in such applications as supercapacitors, light-emitting diodes, and organic optoelectronic devices, among others.

Synthesis and characterization of chitosan-based pH-sensitive biofilm: An experimental design approach for release of vitamin B12

Hydrogels because of their unique potentials, such as highwater content and hydrophilicity, are of interest for the controlled release of drug molecules. In the present study, a biofilm was produced using chitosan, a natural polymer. Characterization analyses of the synthesized biofilm were performed using Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis-differential thermal analysis, x-ray diffraction, and scanning electron microscopy-energy dispersive x-ray spectrometry. The analysis results of the film before loading were compared to the analysis made after adding vitamin B12 to the film. The release percentage of vitamin B12 was investigated by using ultraviolet-visible spectrophotometery. The FT-IR bands of vitamin B12 were in the range of 2,800-3,500 cm-1 and 1,000 cm-1-1,750 cm-1. When pH increased from 3 to 7, release of vitamin B12 from the biopolymer increased up to pH 5. While examining the release potential, parameters, such as pH, initial concentration of vitamin B12, release time, and solution volume, were optimized by using response surface methodology. It was determined that with the increase in release time and the initial concentration, pH contributed positively to the release of vitamin B12. The following conditions were determined for release of vitamin B12 from the biofilm: pH: 4.2, initial concentration of vitamin B12: 54.0 mg L-1, the release time: 117 min, and volume of solution: 2.1 mL. The analysis of variance results showed that the determination coefficients for the use of synthesized biofilm in vitamin B12 release were high and R2 =0.9704.

Effect of flame retardants and 1% stabiliser on thermal decomposition and physics properties of thermoplastic polymer due to TGA and DTA tests

This work introduces seven various polymer samples blended in a twin-screw extruder with flame retardants (FR), and an additive, which is a 1% Stabiliser, to investigate thermoplastic polymer melting, thermal decomposition, and melting moderates. The reduction method is used to analyze its melting points, physics and chemical properties, and thermal decomposition. Thermogravimetric Analysis (TGA) and Differential Thermal Analysis (DTA) tests are known as thermal analysis tests. It was established that halogenated flame retardants have little effect on reducing the rate of gas escape from polymer melt which affects the viscosity, as it was found. Thus, the APP and FR245 in Polymer help in some polymer leftovers. All samples were treated with flame retardants and no clay, melted completely, at the end of the test some samples did change. All these results investigated by (the XRD) test either, Scanning Electron Microscopic (SEM) or Digital images have been used also applied Limiting oxygen index (LOI) test, in the previous work for the same samples of polymers to verify the results and record a more precise outcome to draw the relationship between melting and dripping behavior via the following studies due to the furnace test which is modulated and calibrated. As a result, the addition of clay together with conventional flame retardants enhances the overall thermal stability forming the polymer. The compatibles help in improving the dispersion of the clay in polymer and reduce the rate of gas escape from polymer melt affecting the viscosity.

High-temperature oxidation resistance behavior and mechanism of HfSiO4-modified C/SiC composites

To enhance the oxidation resistance of C/SiC composites, HfSiO4 was introduced into C/SiC composites to modify the matrix utilizing two cyclic alternating preparation modes, thereby yielding the C/SiC-HfSiO4 composites with a composite matrix. Using X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), energy-dispersive spectrometer (EDS), and thermogravimetric-differential thermal analysis (TG-DTA), a comprehensive investigation was conducted into the oxidation behavior and mechanism of the prepared composites. Results reveal that the C/SiC-HfSiO4 composites prepared using cyclic alternating preparation modes display the reduced oxidation mass loss and enhanced retention of flexural strength, despite of having higher porosity. In short, the introducing of HfSiO4 can effectively improve the oxidation resistance of C/SiC composites. The effects of the matrix particle refinement and the synergy between the HfSiO4 and SiO2 jointly lead to the enhanced oxidation resistance.