Thermogravimetric Curves Research Articles

Production of AlN/CNT reinforced PVA nanofibers as a thermal conductive net for thermal interface applications

The amount of heat generated by electronic components is increasing daily, in line with their growing power and performance. Consequently, there is a heightened demand for thermal interface materials for enhanced cooling of electronics. This study employs a novel approach to fabricate a nano composite thermal interface material on copper substrates to address this challenge. The thermal interface coatings, consisting of carbon nanotubes (CNT) and aluminum nitride (AlN)-reinforced polyvinyl alcohol (PVA) nanofibers with and without an epoxy resin matrix, are fabricated using the electrospinning technique. The findings demonstrate the successful fabrication of a 2.5 µm-thick CNT/AlN-PVA nanocomposite fiber mat coating with an average fiber diameter of 318 nm onto copper substrates. Scanning electron microscope (SEM) images revealed that the AlN particles and CNTs penetrated the fibers. The successful incorporation of AlN particles into PVA fibers was also verified by the Fourier-transform infrared spectroscopy (FT-IR) spectrum of CNT/AlN-PVA nanofibers. No major weight loss was observed in the thermogravimetric (TG) analysis curves up to 200 °C, indicating the thermal stability of coatings. The thermal diffusivity of the copper substrate coated with the CNT/AlN-PVA nanocomposite fiber mat was measured at 36.6 mm2/s. Moreover, the developed CNT/AlN-PVA nanocomposite fiber mat was also applied on top of the fire-retardant epoxy resin-coated copper substrate, which is conventionally used in electronic devices to provide electrical insulation. SEM images revealed that the existence of an epoxy layer on top of copper substrates did not alter the fiber formation during the electrospinning process, and an approximately 2.5 µm-thick CNT/AlN-PVA nanofiber mat was effectively embedded in the epoxy layer after a 1-hour electrospinning process. The thermal diffusivity of the resulting epoxy matrix CNT/AlN-PVA nanofiber reinforced nanocomposite coating is determined to be 7.792 mm2/s, which is 30-fold higher compared to the thermal diffusivity of neat epoxy resin coatings (0.254 mm2/s).

Study on mechanical performance and mesoscopic simulation of nano-SiO2 modified recycled aggregate concrete

Utilizing nano-SiO2 (NS) to reinforce the old mortar and the weak interfacial transition zone (ITZ) in recycled coarse aggregate (RCA) is a productive approach to enhance the quality of RCA. Throughout this paper, RCA was immersed in NS solutions with different concentrations (2, 5, 10 and 30 wt%). Subsequently, a systematic evaluation of the crushing index and water absorption of the treated NS modified recycled coarse aggregate (SRCA) was conducted. In addition, the calcium hydroxide (CH) content of RCA before and after modification was analyzed by Thermogravimetric and Differential Thermal Analysis (TG-DTA) curves. This study finds that the performance of SRCA modified with 2% concentration achieves comparable modification effects to other concentrations. Additionally, this paper delves into the impact of NS powder on the slump characteristics and compressive strength of concrete. Considering the above research and economic costs, this study adopts 2% concentration of NS for RCA modification and further investigates the stress-strain relationship of NS modified recycled aggregate concrete (SRAC) with various SRCA replacement ratios. Moreover, this paper establishes mesoscopic models of SRAC for various replacement rates and proposes constitutive models corresponding to these rates. The results indicate that when the SRCA replacement rate is within 60%, the stress-strain curve shape of SRAC closely resembles that of natural aggregate concrete (NAC); when the replacement rate exceeds 60%, the descending segment of the SRAC stress-strain curve becomes more precipitous, showing a higher tendency towards fragility in the concrete.

The oxidation reaction mechanism and its kinetics for a carbonaceous precursor prepared from ethylene tar for use as an anode material for lithium-ion batteries

The oxidation reaction mechanism and its kinetics for ethylene tar were investigated in order to obtain a suitable anode material for Li-ion batteries. The oxidation of ethylene tar was divided into 3 stages (350–550, 550–700 and 700–900 K) according to the thermogravimetric curve. To reveal the oxidation reaction mechanism, the components of the gases evolved at different stages were analyzed by mass spectrometry and infrared technology. Based on these results the reaction was divided into 4 stages (323–400, 400–605, 605–750 and 750–860 K) to perform simulation calculations of the kinetics. Using the iso-conversion method (Coats-Redfern) to analyze the linear regression rates (R2) between 17 common reaction kinetics models and experimental data, an optimum reaction kinetics model for expressing the oxidation of ethylene tar was determined and the results were as follows. (1) During oxidation, the side chains of aromatic compounds first react with oxygen to form alcohols and aldehydes, leaving peroxy-radicals on aromatic rings. Subsequently, the aromatic compounds with peroxy-radicals undergo polymerization/condensation reactions to form larger molecules. (2) A fourth-order reaction model was used to describe the first 3 stages in the oxidation process, and the activation energies are 47.33, 18.69 and 9.00 kJ·mol−1 at 323–400, 400–605, 605–750 K, respectively. A three-dimensional diffusion model was applied to the fourth stage of the oxidation process, and the activation energy is 88.37 kJ·mol−1 at 750–860 K. A high softening point pitch was also produced for use as a coating of the graphite anode, and after it had been applied the capacity retention after 300 cycles increased from 51.54% to 79.07%.

Investigation on the early proceeding of cement hydration containing dispersed nano Calcium Silicate Hydrated (CSH) seeds

Steam curing process is a traditional method for accelerating the progression of cement hydration to satisfy the rapid development of compressive strength in precast concrete industry. However, steam curing would release significant amount of CO2 into the atmosphere. In order to avoid the serious environmental pollution caused by the steam curing process, Calcium Silicate Hydrate (CSH) dispersed by comb-like polycarboxylate superplasticizer (PCE), shorted as dispersed nano CSH seed, was utilized to promote the early cement hydration at normal temperature. This investigation aims at disclosing the hydration process of cement and the microstructure evolution of cement paste in the presence of dispersed nano CSH seed during the early stage via setting time, ultrasonic pulse velocity (UPV), compressive strength, conductivity, pH, thermogravimetric (TG), 29Si NMR and nitrogen adsorption/desorption. The results demonstrated that with the dispersed nano CSH seed increasing, the setting process of cement paste was shortened dramatically, the compressive strength and UPV of cement mortar increased significantly especially at 12 h. The variation of conductivity and pH of cement suspension indicated that the ion dissolution process was promoted by dispersed nano CSH seed, which therefore conducive to the precipitation of cement hydration products. TG curves exhibited that the formation of cement hydration products, including CH (Calcium Hydrated), AFt and CSH gel were accelerated by dispersed nano CSH seed. The 29Si NMR (Nuclear Magnetic Resonance) and nitrogen adsorption/desorption results validated that the incorporating dispersed nano CSH seed promoted considerably the polymerization of CSH gel. The aforementioned results are correlated well with the fast formation of microstructure and in turn the rapid development of compressive strength at early age.

Study on Pyrolysis and Oxidation Characteristics of Coal Gangue Based on TGA-DSC.

Coal gangue spontaneous combustion has caused serious environmental and ecological problems. To investigate the reaction kinetic parameters of the gangue and the exothermic characteristics of the spontaneous combustion of the influence of the law, this study employs the thermogravimetric method to explore the characteristic parameters of the pyrolysis and oxidative combustion process of the gangue from the perspective of thermodynamics, and, at the same time, using the differential scanning calorimetry (DSC) on the exothermic effect of the gangue to explore the gangue to obtain the gangue and the original coal TG/DTG/DSC curves to be compared and from the perspective of thermodynamics. The change rule and potential parameters in the pyrolysis and oxidative combustion process of coal gangue (CG) were analyzed, the oxidation kinetic properties of CG were studied, and the reaction mechanism of oxidative spontaneous combustion of CG was further explained. The results show that the TG/DTG/DSC curves of CG in different gas atmospheres will have significant differences in all stages, and in the process of pyrolysis and oxidative combustion, the thermogravimetric curves of CG and those of the original coal show a consistent trend, except for the large difference in peak amplitude in different stages; in different gas atmospheres, as the rate of warming increases, the TG/DTG/DSC curves of the gangue are tilted toward the high-temperature region, they are inclined to the high-temperature region with the increase of the heating rate, and the phenomenon of "hysteresis" of characteristic temperature occurs. The research results provide a theoretical basis for the construction of a spontaneous combustion early warning system based on the fine division of gangue pyrolysis and oxidation combustion stages.

Comparative analysis of adding cotton straw and corn stover to improve the combustion performance of municipal sludge

To address issues of high water content and low calorific value during combustion of municipal sludge, we added water-absorbent, easy-to-burn agricultural waste to improve the overall combustion performance. Cotton straw or corn stover were added to the sludge and mixed at high-speed to compare their capacities for improving combustion performance. Scanning Electron Microscopy (SEM) revealed that cotton straw or corn stover attached to the surface of the municipal sludge particles after blending, while analysis of thermogravimetric curves and activation energies of the blends showed that combustion and exhaustion rates increased significantly when 40% cotton straw or corn stover were blended into the sludge. Using the quadrilateral cut-ring boiler as a prototype, the mix of sludge with cotton straw or corn stover was simulated, and FLUENT software was used to obtain the temperature and pollutant emissions of the boiler. Sludge blended with cotton straw or corn stover increased furnace temperature and reduced SO2 and NO emissions, while that with cotton straw burned at higher temperatures with lower SO2 and NO emissions. Overall, the CO content of sludge combustion was lower when blended with proportions of cotton straw or corn stover under 50%. The findings of this study lay a theoretical foundation for treatment of municipal sludge according to local conditions.

Isolation and characterization of novel bioplasticizers from rose (Rosa damascena Mill.) petals and its suitability investigation for poly (butylene adipate-co-terephthalate) biofilm applications.

The current growing environmental awareness has forced the use of biodegradable plasticizers, which are sustainable and abundant in plant resources. Rose petal plasticizers (RPP) act as an actual substitute for chemical plasticizers in this situation as they are biocompatible and biodegradable. Chemical procedures like amination, alkalization, and surface catalysis are used to extract the natural emollients from rose petals. XRD, FT-IR, and UV studies were used to understand the characteristics of the rose petal plasticizer. Based on the XRD data, the RPP's crystallinity size (CS) and crystallinity index (CI) values were determined to be 9.36nm and 23.87%, respectively. The surface morphology of the isolated plasticizer is investigated using SEM, EDAX analysis and AFM. RPP surface pores with rough surfaces are visible in SEM images, which make them appropriate for plasticizing novel bioplastics with superior mechanical qualities. The plasticizer's heat degradation behaviour is investigated using thermogravimetric and differential thermogram analysis curves. Following the characterization of the synthesised molecules, the plasticization effect was examined using a biodegradable polymer matrix called poly (butylene adipate-co-terephthalate) (PBAT). The reinforcement interface was also examined using scanning electron microscopy analysis. RPP-reinforced films demonstrated greater flexibility and superior surface compatibility at a 5% loading compared to PBAT-only films. Based on a number of reported features, RPP could be a great plasticizer to address future environmental problems.

3D printing of high solid Al2O3 ceramics based on green and renewable photosensitive resin with low viscosity and low shrinkage

AbstractA low‐viscosity bio‐based carbamate acrylate was synthesized by the reaction of pentamethylene diisocyanate derived from pentanediamine with a low molecular weight acrylate hydroxyl ester. The carbamate acrylate was used in the 3D printing of ceramics, and a correlation between the solid content and viscosity of the ceramic slurry was observed. The ceramic slurry exhibits good stability and low shrinkage. The results indicate that the viscosity of the ceramic slurry was 2.11 Pa s with a solid content of 80 wt%, which makes it suitable for digital light processing printing. In addition, a new type of photoinitiator called (2,4,6‐trimethylbenzoyl)bis(p‐tolyl)phosphine oxide (TMO) has been applied, demonstrating excellent potential in ceramic slurry. According to its thermogravimetric curve, a debinding and sintering process was designed, and ultimately an Al2O3 device with a density of 94.49% was prepared.

Synthesis and mechanism analysis of a non-toxic amine-based clay mineral surface hydration intercalation inhibitor

The surface hydration of clay minerals remains a serious challenge for drilling projects. Herein, we synthesized a non-toxic amine-based clay mineral surface hydration intercalation inhibitor (ODBB) whose structure was characterized using fourier transform infrared spectroscopy, mass spectrometry, and proton nuclear magnetic resonance spectroscopy. The inhibitory ability of ODBB was evaluated through isothermal adsorption, X-ray diffraction, thermogravimetric analysis, linear expansion, rolling recovery, and sedimentation stability. The biological toxicity of ODBB was tested with a bioluminescent bacteriological method. The inhibition mechanism was analysed using elemental analysis, atomic absorption spectroscopy, wettability measurement, zeta potential analysis, capacity of exchangeable cation, scanning electron microscopy, and molecular dynamics simulation. The addition of more than 0.5 wt% ODBB resulted in a reduction in the base spacing of Na-MMT/ODBB from 2.10 to 1.31 nm, while the derivative thermogravimetric curve showed a single peak at 50–200 °C. These results showed that the surface hydration of Na-MMT was completely inhibited. Meanwhile, an EC50 value of 93,000 indicated that ODBB was non-toxic. ODBB intercalated into the crystal layer space of Na-MMT, replaced interlayer cations (Na+), adsorbed on the surface (d001) of Na-MMT by electrostatic interactions, and formed hydrogen bonds with the oxygen atoms on the surface (d001). Furthermore, ODBB tightened the crystalline layer and reduced the base spacing through hydrogen bonding and electrostatic forces.

Synthesis of graphene oxide from post-consumer PET bottles by a one-step thermal treatment in air atmosphere for removal of methylene blue

Post-consumer polyethylene terephthalate (PET) bottles are promising raw materials to produce value-added materials. This work uses a simple thermal treatment (TT) in an air atmosphere to transform post-consumer PET (PET-W) into graphene-oxide-like material (GOL). A careful analysis of the thermogravimetric (TGA) curves allowed us to determine the optimal temperature for controlling the oxidative decomposition reactions of PET-W at 412 °C while maximizing the bidimensional character of the products. The products of thermal transformation were characterized by Raman spectroscopy, DRX, FTIR, SEM, EDS, XPS, and BET. The results of the characterization indicate the obtaining of a material (identified here as GOLPET) which is characterized by an ID/IG ratio of 0.61, the presence of oxygenated groups such as CO, C-O-C and phenyls at the interphase, and an elemental composition of ∼83.7 (wt.%) and ∼16.27% of carbon and oxygen (wt.%), respectively. XPS allowed us to determine the formation of assembled aromatic chains (Csp2 = 61.53%) and acyclic chains (Csp3=38.47%). Finally, GOLPET absorption capacity was explored for a commercial application such as removing methylene blue (MB dye); complete elimination of MB (99.6%) in an aqueous solution was demonstrated. Considering the annual generation of plastic waste ∼300 million t, the methodology developed in this research can be envisage as an affordable and innovative alternative to produce GO-like materials.

Thermal performance analysis of optimized biomass conversion in developing organic waste biorefinery to achieve sustainable development goals

To make energy sector sustainable, waste to energy system should be used, as statistics of the International Energy Agency (IEA) shows that the lack of renewable energy and environmental degradation are the major pressing problems confronting the global community. However, in south Asian regions, the situation escalates as a result of severe dependency on conventional energy sources, coupled with the limitations and challenges involved in maintaining a green environment and Waste-to-Energy (WtE) strategies. In this region, energy majorly relies on imported conventional fuel. In addition to harming the environment, imported fossil fuel has also increased the risk of geopolitical unrest. In the current research, rice husk is used as a bio-organic waste that is produced in large volumes and a significant byproduct of agro-based biomass sector. In this research, sample composition of rice husk is demineralized in 5% hydro-chloric acid for different burning ratios and the modified thermo-chemical methodology was used to the acidified rice husk at three different heating rates (20 °C min−1, 30 °C min−1 and 40 °C min−1) respectively in thermogravimetric analyzer (TGA). Proximate, thermal and kinetic analysis was used for observing the degradation patterns of demineralized rice husk. Proximate analysis revealed that the leaching of rice husk has successfully infused HCl, resulting in substantial rise in fixed carbon (FC) and calorific value (CV) by 10.53 % and 10.82 % respectively, along with decrease in the carbon footprint of about 60.55%. Thermogravimetric (TG) and derivative thermogravimetric (DTG) curves have shown decreasing behavior of conversion efficiency to the increase in flow rate, with the maximum drop of 12.7 % observed at 40 °C. With the use of the TGA equipment, the conversion efficiency was evaluated based on the sample's peak weight loss. The current study has reported synergistic effect of flow and heating rate on the degradation temperatures, activation energy and reactivity of acidified rice husk. Lowest activation energy 180.46 kJ permole with highest reactivity of 0.01192345 %*min °C was observed at 40 ml and 20 °C combination. Accordingly, degradation temperatures of burning profiles increased due to lower convective cooling and higher temperature gradient within the particle of rice husk sample. In addition, pre-exponential data and slopes of TG curves have validated the results of activation energy obtained from TGA experimentation. The sustainable biomass conversion approach is envisioned to significantly refine the waste bio refinery system to achieve SDGs.

Production and characterization of cellulose acetate using olive tree pruning biomass as feedstock

AbstractOlive tree pruning (OTP) is one of the most abundant sources of biomass waste in the Mediterranean basin. This is especially relevant in southern Spain where olive oil production represents a large part of the economy. Olive tree prunings are mostly either burned or are spread in olive orchards as an organic amendment, or used for heat generation on a domestic scale. However, the lignocellulosic composition of OTP makes it a potential source of biopolymers, thus providing an excellent economic alternative for the olive oil sector. In this work, pretreated OTP fibers were subjected to an optimized alkaline treatment followed by a single‐step bleaching reaction with H2O2. Afterwards, the cellulose pulp was transformed chemically to obtain cellulose acetate. Noncellulosic components were removed effectively from OTP, thus obtaining a pulp highly purified in cellulose with 71% crystallinity and 355 °C maximum degradation temperature. Nevertheless, a very large amount of cellulose (ca. 50%) was eliminated throughout the process, especially during acid pretreatment, which was responsible for 38% solubilization. A similar level of acetylation and degree of substitution was obtained by using acetylation times in the range of 1 to 6 h. No large differences were observed in the infrared spectra and X‐ray diffractograms of the synthesized acetates. However, their thermal stability varied significantly with reaction time, evolving from a multistep degradation pattern to a single and sharp peak between 300 and 400 °C with increasing time. Thermogravimetric curves revealed that at least 5 h (preferably 6 h) were needed to obtain cellulose acetate from OTP with adequate thermal stability for further processing.

Changes in the devolatization kinetics induced by washing pretreatments of short- and long-aged food crop residues

Thermogravimetric curves are measured and modeled to quantify the changes induced by dilute acid or hot water washing on the devolatilization of short- and long-aged potato crop residues. The pretreatments cause more similar behaviors. A six-step devolatilization mechanism for four pseudo-components, previously developed for raw materials, is still applicable. The activation energies remain unvaried whereas small changes in the pre-exponential factors describe the displacement of the devolatilization process at higher temperatures. Instead, the nature and amounts of pseudo-components are significantly modified, especially for dilute acid washing and the short-aged sample. The pseudo-components pectin-hemicellulose and cellulose-starch are enriched in hemicellulose and cellulose, respectively. The corresponding total amounts of volatile generated increase from 19 up to 23–26wt% and from 19–26 up to 37–45wt%, in the same order. The volatile product yields released from the pseudo-component lignin-protein are practically unaltered, but lignin is likely to become largely predominant.

Modification of bacterial cellulose using silk fibroin β-sheet crystals induced by ultrasonication

Silk fibroin (SF) has been continuously explored as a biomaterial due to its biocompatibility, tunability, and self-healing properties. In this work, we present a novel approach to the modification of bacterial cellulose (BC) with SF β-sheet dominant structures induced via ultrasonication. Secondary structure analysis through infrared spectroscopy, thioflavin T assay, and circular dichroism spectropolarimetry revealed a conversion of silk I to silk II structures within the protein mixture. Cold field emission scanning electron microscope images revealed the tightly packed fibers coated with the protein. Thermogravimetric curves demonstrated higher resistance to temperature degradation supplemented by broader and flatter DSC curves attributed to the highly bonded and dense composite. Successful conversion of amide I to amide II and amide III allowed for the more stable β-crystals to contribute to a more thermodynamically stable double-network hydrogel. The conversion of silk I to silk II structures offers a viable and highly biocompatible material that is both thermodynamically and biochemically stable for various potential biomedical applications.

Thermal Decomposition Process of Fireproof Sealant Measured with Thermogravimetric and Fourier Transform Infrared Spectroscopy Analysis and Estimated Using Shuffled Complex Evolution

Fireproof sealing technology is widely used in industrial, commercial, and other public buildings, so the performance of fireproof sealing materials in high temperatures or fire environments must be taken into account as an important factor. Fireproof sealant is considered to be a highly effective adhesive for sealing and fireproofing purposes. To explore its thermal decomposition mechanism and estimate its pyrolysis behaviors, a series of thermogravimetric experiments from 10 K/min to 60 K/min coupled with Fourier transform infrared spectroscopy analysis technology were performed. The results indicated that the thermal decomposition of the fireproof sealant could be divided into three reactions: the degradation of ammonium polyphosphate, melamine, and acrylic acid. In addition, the pyrolysis behavior of the fireproof sealant was compared under two kinds of atmosphere (nitrogen and air). Furthermore, the initial kinetic parameters in the nitrogen atmosphere were calculated based on model-free methods including the Friedman, KAS, and Starink methods. The average activation energy of three reactions obtained by the three methods was 108.32 kJ/mol, 200.46 kJ/mol, and 177.10 kJ/mol, respectively, while these obtained parameters were hard to regenerate, the thermogravimetric curves were accurately based on the established pyrolysis reaction scheme, with the existence of clear deviations. Therefore, a global heuristic optimization algorithm, Shuffled Complex Evolution (SCE), was selected to optimize 14 parameters (including activation energies and the pre-exponential factors) and the optimized pyrolysis results agreed well with the experimental data, even at the extra heating rate, with the correlation coefficient for the mass loss and mass loss rate being reaching up to 0.9943 and 0.9019, respectively. The study indicated that the SCE algorithm showed an appropriate potential to estimate the pyrolysis behavior of an unknown thermogravimetric experiment group.

Optical characterization and electrical behavior of bismuth oxide nanoparticles modified PEO/PVP matrix via laser ablation for electrical applications

The effect of bismuth oxide (Bi2O3) nanoparticles synthesized via laser ablation route on polymeric materials composed of PEO/PVP blend was studied. The future utilization of these materials is highly dependent on their structural, morphology, thermal, and electrical qualities being improved. The observed disappearance of the patterns at 2θ = 19.6° and 23.7° in XRD can be attributed to the elevated temperature resulting from the laser beam, which in turn causes the breakup of PEO-PVP chains which confirm the incorporation of Bi2O3 nanoparticles in PEO-PVP complex. The crystal size of Bi2O3 nanoparticles has been determined to be 20 nm. FT-IR spectra confirms the interactions between Bi2O3 nanoparticles and PEO-PVP matrix. Ultraviolet/Visible (UV–Vis) analysis obtains reducing in band-gap by increasing Bi2O3 nanoparticles concentration upon the blend. The change in surface morphology is confirmed by FESEM images by appearing white spots on the surface of PEO-PVP and increasing cluster size of PEO of composite by addition of Bi2O3 NPs. Also, the thermal stability is improved by shifting Thermogravimetric (TG) curves doped with Bi2O3 NPs toward higher temperature by increasing ablation time. Electrical conductivity results show reducing in both dielectric constant (ε′) and dielectric loss (ε'') as the frequency rises. The modifications in both optical and electrical conductivity characterization lead to optimizing compositions in electrical applications.

Synergistic effect study of Chlorella vulgaris and polyethylene in co-pyrolysis process based on kinetic and thermodynamic analysis

The co-pyrolysis of algae and plastics shows great potential for bio-oil production. In this study, thermogravimetric analyzer was used to investigate the pyrolysis behavior of Chlorella vulgaris (CV) and polyethylene (PE) at different mixed ratios and heating rates. Their synergistic effects were discussed through kinetic and thermodynamic analyses. According to the thermogravimetric (TG) and Derivative thermogravimetric (DTG) curves, the co-pyrolysis process can be divided into five stages, corresponding to the decomposition of moisture, carbohydrates, proteins, lipids, and biochar, respectively. In the fifth stage, a clear synergistic effect is observed, with the highest ∆TG reaching about 4%. During the co-pyrolysis process, the average activation energy of the mixtures is much lower than expected, indicating the presence of a synergistic effect in co-pyrolysis. Among them, 3CV1PE is the optimal mixing ratio, with the average activation energy of 3CV1PE being 6% lower than that of CV pyrolysis alone. The master plots revealed that the power law reaction models (P3 and P4) are suitable for describing the experimental behavior of mixtures with higher CV content, while the third-order (F3) and eighth-order model (F8) are more appropriate for the decomposition reaction with higher PE content. The calculation of thermodynamic parameters further show that the co-pyrolysis of CV and PE is beneficial to the decomposition process, and the mixed ratio of 3:1 is the most favorable for the reaction. Results obtained in this work are valuable for guiding research on the co-pyrolysis of biomass and plastics.

Fabrication and Characterization of Eco-Friendly Polystyrene Based Zinc Oxide-Graphite (PS/ZnO-G)

One of the most significant environmental challenges nowadays is the rising manufacturing of non-biodegradable polymer wastes like polystyrene. In order purpose of manufacture environmentally friendly polystyrene that easily decomposes, a solvent approach was used to create polystyrene based zinc oxide- graphite composites. The surface morphology and materials contained in the modified polystyrene were evaluated by scanning electron microscopy-energy dispersive X-ray analysis to verify the dispersion and distribution of the nanoparticles by scanning electron microscopy and the material contents by energy dispersive X-ray analysis. While the crystal structure, chemical bonds, and functions were determined by X-ray Diffraction and Fourier transform infrared, no change in the chemical structure occurred in polystyrene. Thermogravimetric analysis was used to assess the thermal decomposition. And its results found that the temperature of the decomposition was 46.78° lower in zinc oxide and graphite-based polystyrene composites than in pure polystyrene. It came to light that the presence of zinc oxide nanoparticles causes phase separation and consequently impacts the thermal behaviour of graphite-based polystyrene composites. The phase separation was demonstrated by the Thermogravimetric curves showing two degrading steps. This satisfies the urgent demand to synthesize polystyrene that is eco-friendly and easy to thermally decomposition, as well as easy to recycle, which benefits both the environment and the commercial side.

Amidoxime-Containing Zr and Hf Atomic Layer Deposition Precursors for Metal Oxide Thin Films.

In this article, we discuss the synthesis of eight novel zirconium and hafnium complexes containing amidoxime ligands as potential precursors for atomic layer deposition (ALD). Two amidoximes, viz., (E)-N'-hydroxy-N,N-dimethylacetimidamide (mdaoH) and (Z)-N'-hydroxy-N,N-dimethylpivalimidamide (tdaoH), along with their Zr and Hf homoleptic complexes, Zr(mdao)4 (1), Hf(mdao)4 (2), Zr(tdao)4 (3), and Hf(tdao)4 (4) were prepared. We further synthesized heteroleptic compounds with different physical properties by introducing cyclopentadienyl (Cp) ligand, namely, CpZr(mdao)3 (5), CpHf(mdao)3 (6), CpZr(tdao)3 (7), and CpHf(tdao)3 (8). Thermogravimetric analysis was used for the assessment of the evaporation characteristics of complexes 1, 2, 5, and 6, and it revealed multistep weight losses with high residues. On the other hand, the thermogravimetric analysis curves of complexes 3, 4, 7, and 8 comprising tdao ligands revealed single-step weight losses with moderate residues. Single-crystal X-ray diffraction studies of complexes 1, 3, and 7 showed that all of the complexes have monomeric molecular structures. Complex 7 exhibited a low melting point (75 °C), good volatility, and high thermal stability compared with other complexes. Therefore, an atomic layer deposition process for the growth of ZrO2 was developed by using ZrCp(tdao)3 (7) as a novel precursor.

Elaeis guineensisleaves for potential renewable sub‐bituminous coal: Optimization of biochar yield by response surface methodology and product characterization

AbstractPyrolysis of oil palm biomass residue can convert the rich organic matter in biomass into sustainable green energy, thereby addressing the challenge of surplus oil palm biomass residue generated during cultivation. Nonetheless, the pyrolysis of oil palm leaves (OPLs) has received limited attention. In this study, design of experiment‐response surface methodology (DoE‐RSM) was employed to identify the optimal combination of reaction temperature, residence duration, and nitrogen (N₂) flow rate for maximum biochar yield. The elemental analysis, high heating value (HHV), functional group, morphology, pore structure, and thermal behavior were assessed. By varying the operational parameters using response surface methodology, the biochar yield increased by 32.6–85.3%. TheDoE‐RSMpredicted a theoretical yield of 52.1% at 344 °C, 146 min, and 3.2 scfh N₂ flow rate. The experiment confirmed a comparable yield of 53.7% at the stated parameters. TheHHVof 24.14 MJ kg−1was recorded under optimal conditions, and was comparable to sub‐bituminous and bituminous coal. Fourier transform infrared analysis validated theOPLbiochar by weakeningO‐H, C=O,C‐OH, andC‐Hpeaks. Scanning electron microscopy images revealed enlarged pores and altered morphology in theOPLbiochar. X‐ray diffraction showed lower crystallinity of theOPLbiochar than the feedstock. Raman spectroscopy showed higherID/IG, indicating a more disordered carbon structure in theOPLbiochar. Thermogravimetric analysis confirmed higher temperature for main devolatilization ofOPLbiochar, and the differential thermogravimetric analysis curve pattern resembled that of Mukah Balingan coal. The findings are helpful for an initiative to convert a large amount of leftoverOPLsproduced during cultivation and to turn them into high value‐added material for a sustainable contribution to a circular carbon economy.