Optimal Synthesis Conditions Research Articles

Preparation of cationic waterborne polyurethane and its application in leather dyeing

The development of organic chromium-free tanning agents is currently a major research focus in leather tanning. However, these agents decrease the electrical potential of the tanned leather, which hampers the absorption of subsequent anionic dyes and fatliquoring agents. Consequently, issues such as lower color fastness, poor dyeing effects and environmental pollution arise. To address these challenges, this study proposes the utilization of anionic polyurethane (CWPU) as a dye fixing agent to enhance its performance and application in the leather preparation process. CWPU was successfully synthesized using polycarbonate diol (PCDL), isophorone diisocyanate (IPDI), polypropylene glycol (PPG), and N-methyldiethanolamine (MDEA) as raw materials, and the optimal synthesis conditions were optimized. The experimental results showed that the synthesized CWPU color fixing agent exhibited excellent emulsion properties and comprehensive performance when the PCDL: PPG ratio was 1:1 and the MDEA addition amount was 6 wt%. When applied to leather color fixation, the leather not only achieved improved dry and wet rubbing fastness levels of 4–5 but also demonstrated significant improvements in solvent wash resistance and perspiration fastness. Furthermore, the leather treated with CWPU color fixing agent exhibited deeper color and improved physical and mechanical properties and tactile quality. Therefore, this study provides an effective choice of color fixing agent for environmentally friendly chromium-free tanning systems and has broad prospects for the application of acid dyes.

Lentils/urea as precursors for profound S and N doping of carbon dots for selective sequential determination of Hg(II) and S(II) in food and environmental samples

In this article, we described a new platform for probing toxic pollutants, namely Hg2+ and S2-, in aquatic environment by tracing the “on–off-on” fluorescence signals of quantum dots. To achieve this, red lentils and urea, as natural precursors, were utilized as sources of S and N doping, respectively, to fabricate blue fluorescent carbon quantum dots, namely, lentils/urea quantum dots (LUQDs) with good quantum yield and plentiful S-doping. In the present work, the quality-by-design (QbD) strategy was applied to control and select the optimum conditions for the microwave-aided synthesis of the carbon dots. LUQDs exhibit excitation-dependent emissions, where the maximum fluorescence emission was at 360 nm after excitation at 300 nm. During the detection step, the fluorescence of LUQDs is quenched by the incorporation of Hg2+ over the range of 0.50–70.0 μM. Next, S2- reacts with Hg2+, resulting in turning on the fluorescence emission of LUQDs in the range of 10.0–150.0 µM.The method was applied for the detection of both Hg2+ and S2- in tap, sewage, and river water samples with a recovery rate ranging between 98.96 % and 101.26 %; in addition, Hg2+ was detected in canned Tuna samples with a recovery of 98.70 %. Furthermore, the greenness of the developed method was confirmed through various greenness metrics.

Size-Dependent Blue Emission from Europium-Doped Strontium Fluoride Nanoscintillators for X-Ray-Activated Photodynamic Therapy.

Successful implementation of X-ray-activated photodynamic therapy (X-PDT) is challenging because most photosensitizers (PSs) absorb light in the blue region, but few nanoscintillators produce efficient blue scintillation. Here, efficient blue-emitting SrF2:Eu scintillating nanoparticles (ScNPs) are developed. The optimized synthesis conditions result in cubic nanoparticles with ≈32nm diameter and blue emission at 416nm. Coating them with the meso-tetra(n-methyl-4-pyridyl) porphyrin (TMPyP) in a core-shell structure (SrF@TMPyP) results in maximum singlet oxygen (1O2) generation upon X-ray irradiation for nanoparticles with 6TMPyP depositions (SrF@6TMPyP). The 1O2 generation is directly proportional to the dose, does not vary in the low-energy X-ray range (48-160 kVp), but is 21% higher when irradiated with low-energy X-rays than irradiations with higher energy gamma rays. In the clonogenic assay, cancer cells treated with SrF@6TMPyP and exposed to X-rays present a significantly reduced survival fraction compared to the controls. The SrF2:Eu ScNPs and their conjugates stand out as tunable nanoplatforms for X-PDT due to the efficient blue emission from the SrF2:Eu cores; the ability to adjust the scintillation emission in terms of color and intensity by controlling the nanoparticle size; the efficient 1O2 production when conjugated to a PS and the efficacy of killing cancer cells.

Synthesis and evaluation of a new scale inhibitor: the modified epoxysuccinic acid copolymer

Polyepoxysuccinic acid (PESA) scale inhibitor is widely recognized as a green and environmentally friendly scale inhibitor. However, its functional group type is single and cannot be used for a variety of scales. Based on this, a modified epoxy succinic acid quaternary polymer scale inhibitor PEAPS was prepared by introducing a variety of functional groups. The effects of scale inhibitor dosage, temperature, and solution pH on the scale inhibition performance of CaCO3, CaSO4, BaSO4, and SrSO4 were studied. At the same time, it is compared with the commonly used oilfield scale inhibitors Polyacrylic acid (PAA), PESA, and Ethylenediaminetetramethylenephosphonic acid (EDTMP). The results show that under the optimal synthesis conditions, the scale inhibition efficiency of PEAPS scale inhibitor on CaCO3 scale and CaSO4 reaches 100%, and the scale inhibition efficiency of BaSO4 and SrSO4 can reach at least 60%. Its comprehensive scale inhibition efficiency is better than other commonly used scale inhibitors under the same test conditions, and it has certain corrosion inhibition performance through static corrosion evaluation. The crystal parameters and micro-morphology of the four scales before and after the addition of scale inhibitor were analyzed using SEM and XRD. The results showed that after adding the PEAPS scale inhibitor, the crystal structure parameters of the CaCO3 scale and CaSO4 scale changed, and the micro-morphology of the four scale crystals also changed, to achieve the purpose of scale inhibition.

Synthesis of a novel biomass waste-based photocatalyst for degradation of high concentration organic pollutants under visible light: Optimization of synthesis condition and operational parameters via RSM-CCD

Reducing electron-hole pair recombination rate under visible light and preventing α-Fe2O3/WO3 nanoparticle aggregation enhances the photocatalytic efficiency. Herein, a novel heterojunction-activated carbon-based photocatalyst (α-Fe2O3/WO3/AC) was successfully synthesized from Rosa Canina seeds and characterized by PL, EIS, Photocurrent, ESR, XPS, LC-MS, FTIR, XRD, SEM, EDS-map, TEM, and BET analyses. Investigating the influence of significant parameters, including impregnation ratio (1–5), activation temperature (400–600 °C), and α-Fe2O3/WO3 loading (10–90 wt.%) by RSM method resulted in optimal photocatalyst synthesis (50 wt.%: FeW/AC3–500) evidenced by its capability for doxycycline degradation. The maximum doxycycline degradation (98.01 %) was achieved under optimal conditions with a degradation rate constant of 0.03 min−1. Trapping experiments revealed that •OH and •O2− played crucial roles in photocatalysis. The possible doxycycline degradation pathway of (50 wt.%: FeW/AC3–500) photocatalyst is proposed. Based on the transient photocurrent measurements and EIS results, the 50 wt.% FeW/AC3–500 composite exhibited a significant enhancement in photocatalytic activity, which can be attributed to the efficient speed of electron-hole separation. Overall, an innovative approach was introduced to design an efficient AC-based photocatalytic process, which enhances the performance of wastewater treatment and environmental remediation.

Simple and rapid synthesis of zeolite W from K‐feldspar via the improved hydrothermal method

AbstractAn improved hydrothermal method was proposed to rapidly synthesize zeolite W from alkali fusion‐activated K‐feldspar. The effects of m (KOH)/m (K‐feldspar), n (SiO2)/n (Al2O3), n (H2O)/n (SiO2), crystallization time, and crystallization temperature on the synthesis of the zeolite W were investigated. The optimal synthesis conditions were m (KOH)/m (K‐feldspar) ratio of 1.5:1, the activation time of 2 h, and the activation temperature of 500°C, n (H2O)/n (SiO2) ratios of 42, n (K2O)/n (SiO2) of 0.90, n (SiO2)/n (Al2O3) of 5, crystallization time of 6 h, and crystallization temperature of 150°C. The mechanism for rapid synthesis of zeolite W was illustrated. In this process, Na2SiO3·9H2O and Al2(SO4)3·18H2O were first dissolved rapidly in the synthesis system to form an amorphous gel, which contributes to the accelerated crystallization process. Compared with the state‐of‐the‐art synthesis method, this method remarkably decreases the water content to be added in the synthesis process and crystallization time, avoids the pre‐preparation process of the xerogel, and enhances the utilization rate of K‐feldspar. This work provides an industrial‐friendly synthesis process of zeolite W and could realize the highly efficient utilization of K‐feldspar.

Microwave assisted synthesis of nickel oxide nanoparticles at different pH via sol gel method: Experimental and first-principles investigations

Nickel oxide (NiO) nanoparticles were synthesized at different pH levels via a sol–gel method and calcined using microwave assistance. The study explored the effects of pH on NiO nanoparticles morphology, structure and electronic properties. Density functional theory (DFT + U) calculations were employed to investigate the structural and electronic properties of the material. NiO synthesized at pH 8 displayed superior crystallinity and particle size distribution, with spherical-like nanoparticles averaging 3 nm in size. DFT + U calculations revealed a band gap of 4.07 eV and a surface energy convergence of 51 meV/Å2, indicating stability. These findings suggest pH 8 as the optimal condition for NiO synthesis. Electrochemical tests demonstrated a high specific capacitance of 87.7F g−1 at a scan rate of 10 mV s−1, indicating promising electrochemical properties for supercapacitor applications.

Preparation of C-S-H seeds from solid waste and its application as Portland cement accelerator

C-S-H seeds are expected to be a new type of accelerator to cope with the challenges of reduced strength and poor durability of concrete in the later stage caused by high dosage of accelerator. In this study, two solid wastes, rice husk ash and carbide slag, were used as silicon and calcium sources to synthesize C-S-H seeds. By screening the particle size and solid content of C-S-H seeds, the optimum synthesis condition was determined to be stirring at 25 °C for 2 h. The average particle size of synthesized C-S-H seeds approximates this to 320 nm and was mainly composed of C-S-H gel, PCE and sodium nitrate. The effects of C-S-H seeds on the properties of cement paste were studied by experiments such as fluidity, setting time, compressive strength, heat of hydration, XRD, TG and MIP. The results showed that the addition of C-S-H seeds improved the fluidity of cement paste, shortened its setting time, accelerated its early hydration, especially the NG process, and significantly improved its early compressive strength. Meanwhile, it densified the cement paste and improved the compressive strength in the later stage. The C-S-H seeds synthesized in this study not only showed excellent acceleration, but also were based on solid waste as raw material, while the reaction time was short and the equipment requirements were low.

Extending the Scope of the C-Functionalization of Cyclam via Copper(I)-Catalyzed Alkyne-Azide Cycloaddition to Bifunctional Chelators of Interest.

Cyclam, known for its potent chelation properties, is explored for diverse applications through selective N-functionalization, offering versatile ligands for catalysis, medical research, and materials science. The challenges arising from N-alkylation, which could decrease the coordination properties, are addressed by introducing a robust C-functionalization method. The facile two-step synthesis proposed here involves the click chemistry-based C-functionalization of a hydroxyethyl cyclam derivative using Cu(I)-catalyzed alkyne-azide cycloaddition (CuAAC). Boc-protecting groups prevent undesired copper coordination, resulting in compounds with a wide range of functionalities. The optimized synthesis conditions enable C-functional cyclams to be obtained easily and advantageously, with high application potential in the previously cited fields. The methodology has been extended to trehalose-based Siamese twin amphiphiles, enabling efficient gene delivery applications.

Horseradish peroxidase immobilized in calcium alginate-gelatin hybrid beads with high stability against metallic ions and organic solvents

Horseradish peroxidase (HRP) was immobilized in hybrid calcium alginate-gelatin hydrogel beads by entrapment. Then, organic solubility, metal ion compatibility, pH/temperature studies of the synthesized materials have been carried out. Hybrid beads (Ca-Alg@gel-HRP) were synthesized under optimum synthesis conditions with high yield and specific activity. The synthesized bead size was determined to be approximately 0.29 mm in diameter, hydrogel structure and transparent appearance. Accordingly, the optimum pH of free HRP and Ca-Alg@gel HRP was found to be pH 6 and 5 and the optimum temperature was found to be 40 °C and 60 °C respectively. For all identified metal ions except Fe2+, the Ca-Alg@gel HRP had a higher activity than the free HRP. In the presence of 1 mM Na+, Ca2+, Mg2+, Ba2+, Cu2+, Ni2+, Mn2+, Hg2+ ions, the activity increased by more than 20%. The relative activity was also approximately 153%, 150% and 145% in 2.5 mM chloroform, glycerol and DMF. Free enzyme activity was reduced by more than 30%. The Ca-Alg@gel HRP at room temperature and 4 °C retained most of its activity after 14 days. In cycle 5, it had half the activity. As a conclusion, it may have significant potential in a number of industrial processes, particularly in organic synthesis, because it is tolerant to metal ions and organic solvents and is a cheap, practical and simple immobilization method.

Catalytic Degradation Efficacy of Silver Nanoparticles Fabricated Using Actinidia deliciosa Peel Extract

The preparation of metallic nanoparticles using green synthetic approaches and its application toward the efficient degradation of environmentally hazardous dyes constitutes an attractive alternative to currently employed methods. In the current report, the green synthesis of silver nanoparticles (AgNPs) was successfully achieved using Actinidia deliciosa (kiwifruit) peel aqueous extract as a bioreducing agent under optimized synthesis conditions. The experimental parameters were optimized in terms of reactant ratio, reaction temperature, and reaction time. The biogenic nanoparticles exhibited SPR absorption band at λmax 480 nm. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) images revealed quasispherical monodisperse nanoparticles which were 36 nm in diameter. The hydrodynamic diameter of the nanoparticles was 106 nm as determined by dynamic light scattering, and the highly negative ζ-potential (−34 mV) supported its superior colloidal stability. Energy dispersive X-ray confirmed that silver is a major constituent of the nanoparticles. X-ray diffraction (XRD) diffractograms confirmed the crystallinity of the nanoparticles and its face-centered cubic (fcc) lattice structure. The functional groups in the plant’s phytochemicals facilitating the reduction of Ag+ ions and stabilization of the formed AgNPs were identified by fourier transform infrared (FTIR) spectroscopy. In specific, the bands in the FTIR spectra at 3,412, 1,618, 1,419, and 1,237 cm−1 suggested the presence of phenolic compounds. Phytochemical analysis by colorimetric assays revealed that the kiwifruit peel extract was rich in phenolic compounds. When evaluated in the catalytic degradation of organic dyes, the biosynthesized AgNPs induced instant and complete discoloration of the methylene blue dye when 1.6 mg of nanoparticles was used. At a lower dose of AgNPs (0.4 mg), 80% degradation of the dye occurred after 3 hr of treatment. The degradation reaction followed second-order kinetics with a rate constant of 0.01083 mM−1s−1. The current study highlights the immense potential of the prepared nanoparticles as efficient catalysts for the degradation of hazardous organic dyes such as methylene blue and presents an intriguing argument for investigating the catalytic efficiency of the biogenic AgNPs for the degradation of other structurally different dye pollutants.

Charge/discharge performance of flame-synthesized TiO2/C composite nanoparticles as anode materials

A flame-synthesized TiO2-based anode material was developed by conducting in-situ composition of TiO2 particles and amorphous carbon particles in a flame. The particle characteristics of the collected composite particles were subsequently examined, and the performances of lithium-ion secondary batteries that used these composite particles as anode materials were measured and evaluated. The aggregates of synthesized and collected particles were confirmed through SEM, EDS, and XRD analysis, revealing a mixture of amorphous carbon particles and TiO2 particles with ranging in size from about 40 to 80 nm. Analysis of the charge/discharge test results on these coin cells indicates that TiO2 and amorphous carbon determine capacity retention and discharge capacity, respectively. Considering both capacity and retention of the cells, optimal flame synthesis conditions were found.

Optimization of the Synthesis and Radiolabeling of ZIF-8 Nanoparticles.

Lately, there has been increasing interest in the benefits of metal-organic frameworks, and among them, zeolitic imidazolate frameworks (ZIF - 8) stand out as one of the most commonly employed systems owing to their unique characteristics. Given that properties like particle size play a key role in biomedical applications of nanoparticles, optimizing the synthesis conditions becomes crucial. Additionally, it is essential to label these nanoparticles to track them effectively within the body. Zeolitic imidazolate frameworks nanoparticles were synthesized under various conditions, including high and room temperature, using two different solvents: Water and methanol. Modifications were made to the reaction temperature and the ratio of reactants to improve the outcomes. Particle size and size distribution were assessed in all conditions. Additionally, the radiolabeling of nanoparticles was examined using four different methods to identify the method with the highest efficiency and radiochemical purity. The optimum conditions for ZIF-8 synthesis were determined at 50°C using methanol as the solvent. A reactant weight ratio of 1: 2 (zinc nitrate to 2-methylimidazole) was utilized. The most effective radiolabeling approach involved using tin chloride as a reducing agent, with the reaction mixture maintained at a temperature of 70°C for 30 minutes. In this study, the optimum conditions were successfully identified for synthesizing and labeling ZIF-8 nanoparticles. These nanoparticles have the potential to serve as effective carriers for diagnostic and therapeutic agents.

Effects of Calcination Conditions on the Structural and Electrochemical Behaviors of High‐Nickel, Cobalt‐Free LiNi0.9Mn0.1O2 Cathode

AbstractEliminating cobalt from high‐nickel layered oxide cathodes lowers the cost of lithium‐ion batteries for electric vehicles. However, cobalt‐free cathodes with high Mn4+ and Ni2+ contents are prone to Li/Ni mixing after synthesis, potentially compromising battery energy density, rate capability, and cycling stability. Without cobalt facilitating cation ordering in the layered structure, the degree of Li/Ni mixing in cobalt‐free cathodes depends heavily on the calcination conditions. In this study, a systematic exploration of calcination temperatures and LiOH ratio for LiNi0.9Mn0.1O2 (NM‐90) provides detailed insights into the optimal synthesis conditions for high‐capacity cobalt‐free cathodes with extended cycle life. Surprisingly, high Li/Ni mixing does not necessarily lead to poor cycling stability whereas low Li/Ni mixing does not guarantee a long cycle life. More importantly, although excessive calcination temperature can further decrease Li/Ni mixing, it does not necessarily enhance capacity. Instead, the pernicious effects from the H2 → H3 phase transition are amplified due to a pronounced two‐phase reaction. An extensive suite of chemical and structural characterization methods uncovers a correlation between elevated calcination temperature, phase transformation, cation ordering, and capacity fading behavior: “overcooking” high‐nickel, cobalt‐free cathodes induce structural arrangement toward that of LiNiO2, with exacerbated lattice distortion and surface instability accelerating capacity fade.

Preparation of a macroporous anion exchange chromatographic medium by polyamine grafting and evaluation of its protein-adsorption behavior

The macroporous anion exchange chromatographic medium (FastSep-PAA) was prepared through grafting polyallylamine (PAA) onto polyacrylate macroporous microspheres (FastSep-epoxy). The effects of the synthesis conditions, including the PAA concentration, reaction time, and reaction solution pH, on the ion exchange (IC) of the medium were investigated in detail. When the PAA concentration, reaction time, and reaction solution pH were increased, the IC of the medium increased, and optimal synthesis conditions were then selected in combination with changes of protein binding capacity. A scanning electron microscope was used to examine the surface morphology of the medium. The medium possessed high pore connectivity. Furthermore, the pore structure of the medium was preserved after the grafting of PAA onto the macroporous microspheres. This finding demonstrates that the density of the PAA ligands does not appear to have any discernible impact on the structure of the medium; that is, no difference in the structure of the medium is observed before and after the grafting of PAA onto the microspheres. The pore size and pore-size distribution of the medium before and after grafting were determined by mercury intrusion porosimetry and the nitrogen adsorption method to investigate the relationship between pore size (measured in the range of 300-1000 nm) and protein adsorption. When the pore size of the medium was increased, its protein binding capacity did not exhibit any substantial decrease. An increase in pore size may hasten the mass transfer of proteins within the medium. Among the media prepared, that with a pore size of 400 nm exhibited the highest dynamic-binding capacity (DBC: 70.3 g/L at 126 cm/h). The large specific surface area of the medium and its increased number of protein adsorption sites appeared to positively influence its DBC. When the flow rate was increased, the protein DBC decreased in media with original pore sizes of less than 700 nm. In the case of the medium with an original pore size of 1000 nm, the protein DBC was independent of the flow rate. The protein DBC decreased by 3.5% when the flow rate was increased from 126 to 628 cm/h. In addition, the protein DBC was maintained at 57.7 g/L even when the flow velocity was 628 cm/h. This finding reveals that the diffusion rate of protein molecules at this pore size is less restricted and that the prepared medium has excellent mass-transfer performance. These results confirm that the macroporous polymer anion exchange chromatographic medium developed in this study has great potential for the high-throughput separation of proteins.

Optimization of preparation conditions of Bi-doped TiO2/montmorillonite composites and its photodegradation of Rhodamine B

In order to improve the photocatalytic degradation performance of titanium intercalated montmorillonite composites, the sol-gel method was used to intercalate bismuth/titanium polymerized hydroxyl cations into the interlayer of sodium-based montmorillonite (Na-MMT). The optimum synthesis conditions of Bi-doped TiO2/montmorillonite composite photocatalytic material (Bi/Ti-MMT) were investigated. Powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM) and UV–vis diffusion reflectance spectrum (UV-Vis DRS) had been used to study the formation of Bi/Ti-MMT. Under the conditions of Bi/Ti molar ratio of 7 %, montmorillonite suspension mass fraction of 2 %, calcination temperature of 600 ℃ and calcination time of 3 h, the Bi/Ti-MMT had the highest photocatalytic activity, the degradation rate of Rhodamine B (RhB) was 88.16 %. In Bi/Ti-MMT composites, TiO2 existed in anatase phase. Bi3+ replaced Ti4+ and was doped into the TiO2 lattice, which can inhibit the growth of TiO2 crystals and reduce the band gap. The photoresponse range of the composite material was broadened to visible light, which improved the utilization of light.

Determination of Optimal Conditions for Template Sol-Gel Synthesis for the Formation of Antibacterial Materials

Determination of Optimal Conditions for Template Sol-Gel Synthesis for the Formation of Antibacterial Materials

Synthesis of Sugarcane Bagasse Based Zeolite and Optimization of Particle Size, Reagent Ratio, Contact Time, and Microwave Influence

The persistent contribution of agricultural wastes to the total global solid waste underscores the urgent necessity for environmentally sustainable approaches to their management. This study explored the synthesis and optimization of zeolite derived from cost-effective sugarcane bagasse via microwave sintering, employing four key process variables: particle size (90-200 µm), reagent ratio (0.5-1), contact time (10-20 min.), and microwave power (400-700 W), through a full factorial design. The investigation revealed that these parameters exerted diverse influences on the porosity of the resultant zeolite. Optimal synthesis conditions were identified at particle size of 200 µm, reagent ratio of 0.5, contact time of 20 minutes, and power of 400 W. A linear model was developed for this process with indices such as R² (0.9976), Adjusted R² (0.9823), Predicted R² (0.8492), Adeq Precision (28.3118), Std. Dev. (0.5942) and C.V. % (0.9632) indicating the high accuracy of the model and its adequacy for predicting the porosity of the produced zeolite with good precision. Additionally, the enhanced porosity exhibited by the synthesized zeolite indicated heightened adsorptive capacity. The substantial adsorption potential of the optimized zeolite thus offers promising prospects for wastewater treatment, effectively addressing numerous environmental challenges and transforming waste into wealth.

Green synthesis of silver nanoparticles using Houttuynia cordata Thunb rhizome extracts and their antibacterial potential against common foodborne pathogens

SummaryThe biological synthesis of functionalised nanoparticles using plant materials is considered more cost‐effective and eco‐friendly than chemical and physical methods. Hence, this study demonstrated the synthesis of silver nanoparticles (AgNPs) using Houttuynia cordata Thunb rhizome (HCR). The extract, prepared with distilled water, provided the required phytochemical components, such as flavonoids, terpenoids, phenols, proteins and other essential bio‐reducing agents. The AgNPs were exposed to reaction conditions, such as temperatures, pH values and AgNO3 concentrations, to identify the optimum synthesis condition and explore their impacts on particle size and antibacterial action against Gram‐positive (Staphylococcus aureus) and Gram‐negative (Salmonella enterica and Shigella dysenteriae) foodborne pathogens. The formation of AgNPs was indicated by specific surface plasmon resonance (SPR) intensity at 440–450 nm and colour changes under different reaction conditions. The structure and size distribution characterised by SEM and TEM revealed that the AgNPs exhibited a spherical‐shaped structure with irregular contours, regular distribution and aggregation. Although the average particle size ranged from 2 to 100 nm, relatively smaller sizes were detected at 10 mM (54.30), 80 °C (49.50 nm) and pH 6 (60.16 nm) conditions. The FTIR spectrum and EDX spectral signals affirmed the presence of reducing and stabilising agents in HCR extract, following the reduction of AgNPs from Ag+ to Ag0. AgNPs also exhibited excellent antibacterial activity against S. aureus, S. enterica and Sh. dysenteriae, indicating a broad spectrum for various applications in the food and pharmaceutical industries.

Optimization of synthesis parameters of PUF/ENB microcapsules for self‐healing applications using factorial design methodology

AbstractThis study introduces a systematic experimental approach aimed at enhancing the production process of poly(urea‐formaldehyde) (PUF) microcapsules filled with 5‐ethylidene‐2‐norbonene (ENB) using in situ emulsion polymerization. Essential parameters were identified through a prior Plackett Burman (PB) design, leading to the implementation of a 24‐1 fractional factorial design. The key parameters selected encompassed stirring speed, poly(ethylene‐alt‐maleic anhydride) (EMA) emulsifier content, pH of the reaction, and the quantity of 1‐octanol. Optimal conditions for polymeric microcapsule synthesis were determined using a statistical analysis of the complete factorial design, facilitating the development of representative mathematical models for the process. A comprehensive evaluation of response variables including microcapsule diameter, yield, encapsulated content, stability, and thermal degradation was conducted. Utilizing response surface analysis (RSM), it was determined that the PUF/ENB(2C) condition (stirring at 700 rpm, a reaction pH of 3.0, and EMA content of 0.425 g) resides within the optimized synthesis region, producing microcapsules exhibiting favorable morphological characteristics, yield of 52% and encapsulated content of 80%.