Silica Nanoparticles Research Articles

Extracellular matrix mimetic supramolecular hydrogels reinforced with covalent crosslinked mesoporous silica nanoparticles.

The extracellular matrix (ECM) is a dynamic environment that is primarily built up from fibrous proteins (e.g., elastins, fibronectins, collagens, and laminins) and plays a vital role in tissue regeneration processes. Therefore, the development of supramolecular hydrogels that can mimic the ECM's dynamicity and fibrous structure is of great interest in regenerative medicine. However, such hydrogels generally have weak mechanical properties and poor structural stability, which significantly limits their potential applications. To overcome this drawback, we developed a new type of hybrid network composed of supramolecular assemblies with covalent nanoparticle-based crosslinkers. The ECM mimetic hydrogels were created through UV-initiated thiol-ene crosslinking between norbornene functionalized benzene-1,3,5-tri carboxamide (NBTA) macromonomers and thiol functionalized mesoporous silica nanoparticles (MSN). We hypothesized that the MSN would improve the mechanical properties by crosslinking the NBTA supramolecular fibrous hydrogels. Notably, the covalent incorporation of MSNs did not disrupt the fibrous morphology of the resulting NBTA-MSN nanocomposites. Furthermore, these supramolecular nanocomposites demonstrated higher structural stability and elasticity compared to pristine NBTA hydrogels. Rheology studies showed that the mechanical properties of NBTA-MSN hydrogels could be tuned by adjusting MSN wt%. Interestingly, NBTA-MSN nanocomposites exhibited self-healing and injectability despite the covalent crosslinking of MSNs. In vitro studies confirmed that NBTA-MSN nanocomposites showed good cytocompatibility and maintained the viability of encapsulated MG63 cells. As a proof of concept, we also demonstrated that MSNs could act as ion reservoirs for calcium and phosphate within the hydrogel networks in addition to being covalent crosslinkers. Taken together, our work offers a promising strategy to create hybrid, biomimetic supramolecular nanocomposite materials for various applications such as injectable materials for bone tissue engineering, and reinforced bioinks for 3D printing applications.

Smart Mesoporous Silica Nanoparticles Loading Curcumin Inhibit Liver Cancer.

Curcumin (CUR) as one of the natural edible pigments is approved by the World Health Organization due to its nontoxic and anticancer effect. However, the utility of CUR is restricted due to its low oral bioavailability. Nanoparticle drug delivery systems like mesoporous silica nanoparticles (MSNs) have been extensively used due to their high specific surface area, high loading rate, and ease of modification. This study developed lactobionic acid (LA)-modified carboxymethyl chitosan (CMCS)-coated MSNs to deliver CUR specifically targeting hepatocellular carcinoma. Among these nanoparticles, LA targets liver cancer cells. CMCS utilizes pH-responsive release of CUR. The LA-CMCS-MSN@CUR (MSN@CUR) were evaluated using several methods, including Fourier transform infrared spectroscopy, transmission electron microscopy, and zeta potential measurements. Liver cellular uptake of MSN@CUR depends on a specific LA receptor-mediated endocytosis mechanism. Additionally, MSN@CUR performed with a better antitumor effect than Cur in H22 orthotopic transplantation of liver cancer and H22 solid tumor mouse models. Treatment with MSN@CUR significantly reduced the protein of VEGF, p-PI3K, and AKT, increased the protein of caspases 3 and 8, ultimately inhibited tumor migration, and promoted apoptosis. This study provides a new path for delivery of natural active ingredients with excellent bioavailability in the antitumor field.

Preparation, characterization and mechanism of SiO2@SiO2 core-shell microspheres through polymerization-induced colloid aggregation for fast separation using ultra performance liquid chromatography

The polymerization-induced colloid aggregation (PICA) method is commonly used to create SiO2@SiO2 core–shell silica microspheres (CSSMs), but it often encounters challenges such as incomplete shell coating and poor reproducibility. In this paper, the formation mechanism of the silica shell layer during the preparation of SiO2@SiO2 CSSMs using the PICA method was investigated. It was found that ureido modification can reduce the Zeta potential of the silica core surface, facilitating the deposition of coacervates formed by urea-formaldehyde resin (UF) and silica nanoparticles on the silica core surface to form the SiO2 shell layer when the Zeta potential of the surface is in the range of −20.1 mV to −4.8 mV. By controlling the interfacial state and surface potential of the SiO2 core, the issue of inconsistent reproducibility in preparing SiO2@SiO2 CSSMs can be overcome. Furthermore, optimization of experimental parameters such as pH, reaction temperature, water content, and reaction time can enhance the formation process. The thickness of the shell and pore size of CSSMs can be successfully adjusted by varying the reaction time and the particle size of colloidal silica sol, respectively. With optimal conditions, the semi-scale production yield of SiO2@SiO2 CSSMs can be increased to 50 g. The SiO2@SiO2 CSSMs were modified with octadecyltrichlorosilane (ODS) to be used as stationary phases in reversed phase liquid chromatography (RPLC) for fast separation of small solutes, peptides, and proteins. The superior separation efficiency indicates that the improved PICA method has the potential to be utilized as an alternative to the layer-by-layer method for large-scale production of SiO2@SiO2 CSSMs.

Effect of carbon black and silicon dioxide nanoparticle exposure on corona receptor ACE2 and TMPRSS2 expression in the ocular surface

The Coronavirus disease 2019 (COVID-19) pandemic has led to a global health crisis, including ocular symptoms, primarily targeting the Angiotensin-Converting Enzyme 2 (ACE2) receptor. PM2.5 air pollution may increase infection risk by altering ACE2 expression. Silicon Dioxide (SiO2) and carbon black (CB), major components of PM2.5 from sands and vehicle emissions, were studied for their effects on ACE2 and Transmembrane Protease Serine 2 (TMPRSS2) expression in corneal and conjunctival cells, and ocular tissues. Human corneal epithelial cells (HCECs) and conjunctival epithelial cells (HCjECs) were exposed to nanoparticles (NPs) for 24 hours, assessing viability via WST-8 assay. TNF-α, IL-6, and IL-1β levels in the medium were measured. An in vivo rat study administered NPs via eye drops, with Rose Bengal staining to evaluate damage. ACE2, TMPRSS2, and Angiotensin II (AngII) protein expressions were quantified by Western blot. ACE2 expression in HCjECs increased with NP exposure, while it decreased in HCECs. CB exposure increased TNF-α, IL-6, and IL-1β levels in HCECs. In vivo, corneal exposure to CB decreased ACE2 expression, whereas conjunctival exposure to SiO2 increased ACE2 expression. These changes suggest that SiO2 exposure may increase the risk of COVID-19 through the ocular surface, while CB exposure may decrease it.

A Comprehensive Review of Nano-sized Silica’s Effects on Plant Growth, Molecular Responses, and Biochemical Changes

Silicon (Si) is a tetravalent metalloid and second most abundant on earth approximately 28%. Slags were used in agriculture as a silica fertilizer (10–28% Si); which improvise degraded crop soils, as well as crop growth and disease resistance. Si improves abiotic stress in crop lodging, UV tolerance, improves water uptakes and blocking the NaCl toxicity was observed in Gramineae family. It showed tolerance to biotic stress in terms of physical strengthening of plants against microbial infestation and activation of defensive enzymes such as peroxidase, polyphenol oxidase, lipoxygenase, phenylalanine ammonia lyase. There was an enhanced vegetative growth and germination percentage in varied vegetable crops with 100 to 500ppm range of silica nanoparticles. The plants available Si (H4SiO4) form in soil solution ranges about 0.1 to 0.6 mM and it get absorbed from roots via xylem to shoot containing a specialized cell surface protein called as Nod26-like major intrinsic protein (NIP) of aquaporin family. The list of total genes responsible for uptake of silica form are Low silica genes (Lsi1, Lsi2, Lsi3, Lsi6) and Si efflux transporter genes (SIET3, SIET4, SIET5). The nano-sized silica have been proven to be more validated impact on genes responsiveness via morpho-physiological parameter relationship. It is concluding that, use of silica in commercial crops have deep root to influence the genes and a bright future in its crop growth development aspects.

A retarded foam acid fluid system for low-temperature dolomite geothermal reservoir stimulation and its action mechanisms

Acidizing improves geothermal reservoir productivity by dissolving rocks to increase formation permeability, which is achieved by injecting acid fluids into reservoir formations. However, conventional acid fluids either can not achieve effective acidizing or cause geothermal reservoir damages. Foam acid fluids, which have been applied for oil-gas reservoir stimulation, can realize effective acidizing by retarding acid-rock reactions, and can protect reservoirs. Here, a foam acid fluid system is proposed, aiming at achieving efficient acidizing and reservoir protection in low-temperature dolomite geothermal reservoirs. Formic acid (FA) and acetic acid (HAc) are used to replace a portion of hydrochloride (HCl) acid. Alkyl glycine surfactant AGS-12 is added for foaming, while xanthan gum and nano silica particles are used to stabilize foams. Corrosion inhibitor and ferric ion stabilizer are added to inhibit acid corrosion of steel and ferric ion precipitations. The acidizing effect was evaluated through foam stability, dissolution performance, corrosion inhibition performance, and compatibility. Microscopic observation, field emission scanning electron microscope, and numerical simulation were applied to reveal the mechanisms of temporal evolution of foams and acid dissolution behaviors. Results show that the foam acid fluid with 5 wt% FA, 5 wt% HAc and 10 wt% HCl acid has the best foam stability and retardation effect. Compared to non-foam acid fluid, the decrease degree of the cuttings mass change rate in foam acid fluids exceeds 50 %, and foaming primarily retards acid-rock reactions. Simulation results is consistent with the experiment results, demonstrating that the cuttings dissolve less in FA and HAc. Calcium (Ca) content on the cuttings surfaces after acid-rock reactions in foam acid fluids with FA and HAc is less than that after acid-rock reactions in foam acid fluid with sole HCl acid, indicating that FA and HAc inhibit Ca-bearing mineral precipitations, as formate and acetate ions can chelate with Ca2+. The replacement of HCl acid by FA and HAc contributes to a low corrosivity and good compatibility of the foam acid fluids due to a reduced hydrogen ions resulted from partial dissociation of weak acids. This study shows the feasibility of foam acid fluids during geothermal reservoir stimulation with eliminated reservoir damages.

Dendritic mesoporous silica loaded with gold nanoclusters and their application in immunochromatographic assay.

Novel green-emitting fluorescent microspheres (GreFMPs) were assembled by loading highly luminescent gold nanoclusters (Arg/ATT/AuNCs) ondendritic mesoporous silica nanoparticles (DMSNs) via PEI-mediated electrostatic adsorption. The fluorescence microspheres exhibit excellent monodispersion with average diameters about (254.5 ± 34.6nm). Compared with free Arg/ATT/AuNCs, the GreFMPs have similar fluorescent properties and biocompatibility but superior environmental tolerance. Subsequently, an immunochromatographic assay based on GreFMPs (GreFMP-ICA) has been successfully developed, which is highly selective toward alphafetoprotein (AFP) in human serum. Under the optimal parameters, there is a good linear range between 0.5 and 160.0ng/mL, the limit of detection was found to be about 0.5ng/mL, and the recovery and relative standard deviation are 81.0 ~ 100.6% and 3.5 ~ 16.6%, respectively. These results manifested that the GreFMPs are beneficial for the rational design of the ICA platform, and the proposed GreFMP-ICA has the potential to screen AFP in clinical applications.

Synthesis of novel biodegradable silica nanoparticles to improve performance and reduce the emission of CRDI engine fueled with hydrogen-enriched biodiesel blend

Currently, energy poses the most formidable problem globally. Biodiesel has emerged as a viable option for in-depth investigation due to its renewable nature, biodegradability, and reduced emissions. Biodiesel offers potential threats, including low combustion efficiency and high viscosity, which can be managed by enriching hydrogen and fuel additives. Using biocompatible nanoparticles can significantly mitigate the detrimental outcome of metal-enriched nanoparticles on living species. The current study synthesized novel biodegradable silica nanoparticles using waste incense stick ash using a calcination process. The silica nanoparticles were examined using several approaches such as Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), X-ray diffraction (XRD), and energy dispersive X-ray (EDX). The EDX analysis confirms the synthesized nanoparticles contain silicon (41.91%), oxygen (70.23%), and a small percentage of other elements like potassium (0.43%) and calcium (0.23%). The various concentrations (50, 75, 100, 125, and 150 ppm) of silica nanoparticles were dispersed into B20 (diesel with 20% biodiesel) using a probe sonicator. Hydrogen is supplied to the engine cylinder through the intake manifold, maintaining a constant flow rate of 10 lpm. The finding indicated that the brake thermal efficiency (BTE) improves by 15.58% for hydrogen-enriched B20 fuel blend and 100 ppm nanoparticles (B20HN100). The B20HN100 fuel sample contributes to a significant reduction in harmful emissions.

Antioxidant and Protective Effects of Oleaster Oil Against Silica Nanoparticle-Induced Oxidative Stress and Organ Toxicity in Rats

Nanoparticles have found widespread application in a variety of fields, despite growing worry about their possible hazardous effects on both the environment and human health. In recent years, research efforts have focused on plants and vegetable oils, which have been identified as abundant sources of many bioactive compounds. Many of these substances are known to participate in antioxidant processes. As a result, the current study was designed to investigate the antioxidant and protective properties of oleaster oil against cytotoxicity and oxidative stress induced by silica nanoparticles (SiNPs) in albino Wistar rats. Forty male rats were randomly assigned to four equally sized cohorts: a control group, SiNP-treated group (at a dose of 50 mg/kg), SiNP-treated group supplemented with oleaster oil (at a dose of 2 mL/kg), and those receiving only 2 mL/kg of oleaster oil. The findings demonstrated that SiNPs initiated an oxidative stress environment, as evidenced by higher lipid peroxidation levels and changes in antioxidant defense mechanisms. Antioxidant enzymes were significantly reduced, including glutathione levels between the control and SiNP-exposure treatments (36.01%, 36.59%, 60%), glutathione-S-transferase (29.74%, 29.90%, 13.49%), catalase (24.14%, 28.19%, 30.85%), and tissue superoxide dismutase (11.90%, 37.78%, 37.79%) in the liver, kidney, and heart, respectively. Furthermore, histological investigations revealed significant liver, kidney, and heart damage, as indicated by pathological alterations such as vascular dilatation and congestion, inflammatory cellular infiltration, and hepatocellular dysfunction. Encouragingly, the administration of oleaster oil significantly ameliorated a majority of these detrimental effects. These data suggest a potential protective effect of oleaster oil against the adverse histological effects induced by SiNP injection.

Preparation and characterization of core-shell structured CaCO3-SiO2 and hollow silica nanoparticles and evaluation of their effects on cement mortar properties

CaCO3-SiO2 particles having a core-shell nanostructure were produced by a modified Stöber process using CTAB as a surfactant. Then, a porous structure composed of a silica shell was formed after the removal of the CaCO3 cores as templates from the nanocomposite. To evaluate phase constitutions and microstructures of prepared nanoparticles, XRD, TEM, and FESEM–EDX techniques were utilized. The main aim of this work was to examine the usability of prepared CaCO3-SiO2 and SiO2 hollow shell nanoparticles instead of OPC in structural applications. In this way, the mixtures of cement mortar were made by partial replacement of 1% of cement mass with prepared nanoparticles. The amounts of calcium hydroxide (CH), bound water, and calcium carbonate for the prepared mortars have been calculated after 7 and 28 days of hydration through thermal analysis of TG/DTG. The results indicated that the CH content decreased by adding prepared nanoparticles as a cement replacement. As CaCO3-SiO2 and hollow SiO2 nanoparticles were used, the compressive strengths of mortars were enhanced by 34 and 59%, respectively, after 28 days, which were higher than the increasing influences on flexural strengths (29 and 55%). The increasing intensity of the XRD peaks related to the C-S-H phases and the decline of the orientation index of CH in a mortar containing silica shell suggest that hydration was further completed, leading to a strength improvement. The SEM micrographs indicated that the addition of prepared nanostructures improved the interface properties inside mortar and caused the microstructure to be denser.

Design, development and effect evaluation of silica nanoparticles on the physical, mechanical, and tribological behaviour of jute/palmyra fiber-reinforced hybrid nanocomposites

Design, development and effect evaluation of silica nanoparticles on the physical, mechanical, and tribological behaviour of jute/palmyra fiber-reinforced hybrid nanocomposites

Damping and acoustic properties of nanosilica filled poly(styrene-acrylate) interpenetrating polymer networks (IPNs): Effect of nanocomposite preparation method

Research on noise pollution reduction has focused on utilizing damping coatings and polymer nanocomposites to enhance sound absorption. Nanosilica/poly(styrene-acrylate) nanocomposites as a water-based coating were prepared through in-situ emulsion polymerization and direct mixing methods at varying concentrations of 1, 2, and 3 wt% of nanosilica. Fourier transform infrared (FTIR) spectroscopy revealed that the inclusion of surfactant-containing micelles and a more extended synthesis period in the in-situ synthesis technique enhanced the interaction between silica nanoparticles and polymer chains. Dynamic light scattering (DLS) analysis showed a unimodal distribution and an acceptable range of polydispersity index (PDI) for neat and nanocomposite latexes. The addition of silica nanoparticles enhanced the stability of latex particles, especially evident in the direct mixing method. The field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) images confirmed the better dispersion of nanoparticles within the polymer matrix in the in-situ method. The addition of nanosilica resulted in a significant increase in pseudoplastic behavior and viscosity, notably in the in-situ synthesis. In both the in-situ synthesis and direct mixing techniques, the addition of 1 wt% of nanosilica resulted in an increase in the damping factor of nanocomposite films to about 2. However, when the nanosilica content was further increased to 3 wt%, the damping factor decreased. Acoustic tests demonstrated improved sound absorption with silica nanoparticles, yielding noise reduction coefficient (NRC) values of 0.49 and 0.46 for in-situ synthesis and direct mixing. The direct mixing method notably enhanced tensile properties at all nanoparticle content levels. Dried nanocomposite films exhibited superior UV-blocking capabilities compared to neat polymer films.

Mechanically robust and durable polyurethane-based superhydrophobic coating containing silica nanoparticles derived from hydrothermal assisted sol–gel method

In the current study, a suspension of hydrothermal assisted sol–gel synthesised superhydrophobic silica nanoparticles (h-SNPs) are sprayed over apartially cured polyurethane (PUR) surface on aluminium substrate. The surface exhibited superhydrophobic (SH) property with a water contact angle of 166 ± 2° and awater sliding angle of < 5°. X-ray diffraction study confirmed the formation of amorphous silica nanoparticles. The particle size determined by field emission scanning electron microscope is about 19–21 nm. The roughness of the coating is 3.5 µm as characterised using a surface profilometer. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy investigations indicated the presence of urethane linkages from PUR and siloxane stretching from h-SNPs. The adhesion of the coating tested with a cross-hatch cutter as per ASTM D3359 shows a rating of 5B. The coating qualified mandrel bend test conducted according to ASTM D255. No cracks are observed at the deformed areas and water drops roll off the surface, demonstrating the integrity of the coating and its superhydrophobicity. The coating exhibits high robustness as evident from sandpaper abrasion and tape peel tests. When compared to superhydrophobic polyurethane (SH PUR) coating developed using commercial silica as reported in our previous work, the developed h-SNPs coating is much more durable as confirmed by accelerated weathering test and anti-icing test. The SH coating also exhibits superhydrophobicity even after 200 h of accelerated weathering test and 16 de-icing cycles. The coating withstands 15 days of water immersion and also displays self-cleaning property.

Formation of Superhydrophobic Coatings Based on Dispersion Compositions of Hexyl Methacrylate Copolymers with Glycidyl Methacrylate and Silica Nanoparticles.

In the last decade, the task of developing environmentally friendly and cost-effective methods for obtaining stable superhydrophobic coatings has become topical. In this study, we examined the effect of the concentrations of filler and polymer binder on the hydrophobic properties and surface roughness of composite coatings made from organic-aqueous compositions based on hexyl methacrylate (HMA) and glycidyl methacrylate (GMA) copolymers. Silicon dioxide nanoparticles were used as a filler. A single-stage "all-in-one" aerosol application method was used to form the coatings without additional intermediate steps for attaching the adhesive layer or texturing the substrate surface, as well as pre-modification of the surface of filler nanoparticles. As the ratio of the mass fraction of polymer binder (Wn) to filler (Wp) increases, the coatings show the lowest roll-off angles among the whole range of samples studied. Coatings with an optimal mass fraction ratio (Wn/Wp = 1.2 ÷ 1.6) of the filler to polymer binder maintained superhydrophobic properties for 24 h in contact with a drop of water in a chamber saturated with water vapor and exhibited roll-off angles of 6.1° ± 1°.

Migrated silicon dioxide nanoparticles activates the rice immunity for systemic resistance against two pathogens

Rice, the world's primary staple food, is under severe threat from several devastating diseases. To sustainably management rice diseases, developing safe, environmentally friendly alternatives urgently need to be developed. In this study, we synthesized two silicon dioxide nanoparticles, spherical mesoporous silica nanoparticles (MSNs) and virus-like mesoporous silica nanoparticles (VMSNs), and we performed a resistance assay on rice for two major diseases, bacterial blight caused by Xanthomonas oryzae pv. oryzae and sheath blight caused by Rhizoctonia solani. Compared to the control, the two nanoparticle treatments increased rice resistance, with VMSNs exhibiting the highest efficacy in controlling these two diseases, causing a shorter lesion length than those plants treated by MSNs. Coincidentally, the foliar application of VMSNs activates a higher expression level of several pathogenesis-related (PR) genes compared to those of MSNs and SiO2 treatment. By using fluorescein isothiocyanate (FITC)-labeled VMSNs (VMSNs-FITC) to soak the top expanded leaf tips or roots, we observed that the fluorescence of the nanoparticles firstly accumulated at the local site of the top leaves or roots, rapidly migrated to the hypocotyl of rice, and then redistributed sequentially from the bottom leaves to the upper leaves. Furthermore, the foliar or root application of VMSNs-FITC could trigger the local and systemic resistance to PXO99. Notably, no significant toxicity was observed on plants and mice after excessive foliar treatment or feeding tests, respectively. Overall, our research revealed that VMSNs are an effective, systemic, and safe nano-pesticides for controlling rice diseases. Boosting the immune responses may be associated with the transporting of nanoparticles.

Mechanisms of Multiple Functional Groups in Post-CMP Cleaning Solutions for Co Interconnects

Cobalt (Co) exhibits low resistivity, excellent adhesive properties, and the ability to fill gaps seamlessly, thus it is promising to change the landscape of integrated circuits in various fields, especially in the areas of interconnections and logic contacts. The cleaning of Co surfaces after chemical mechanical polishing (CMP) is an essential step due to the potential occurrence of numerous defects, such as silicon dioxide nanoparticles, organic residues, and severe corrosion. This research delves into the mechanisms of pivotal components in cleaning solutions, including complexing agents and corrosion inhibitors, and analyzes their impact on cleaning effectiveness. Based on Derjaguin-Landau-Verwey-Overbeek theory calculation and adhesion force measurements through the liquid mode of atomic force microscope, the interaction forces between silica (SiO2) particles and Co substrate were calculated and verified. Additionally, various methods were employed to unravel the nature of the particles and the mechanism of different functional groups, encompassing electrochemical experiments, static etching tests, surface energy studies, zeta potential measurements, and X-ray photoelectron spectroscopy characterization. This comprehensive investigation offers a clear understanding of the roles played by different functional groups, establishes a functional group system for cleaning solutions tailored to Co interconnect wafers, and provides valuable guidance for the subsequent design and development of cleaning solutions.

Exploring synthesis techniques for an imidazole-based one-component epoxy latent curing agent: Chemical capping and mechano-chemical capsuling

The increasing demand for one-component epoxy is driven by its eco-friendliness, convenience, and cost-effectiveness, underscoring the importance of developing latent curing agents that trigger reactions under specific conditions. This study introduces an imidazole-based latent curing agent (ICM-SU) characterized by superior storage stability and low-temperature curing capabilities, achieved through dual protections of chemical capping and mechano-chemical capsuling. The process commences with the synthesis of isophorone diisocyanate capped 2-methylimidazole (ICM), wherein the reactivity of 2-methylimidazole (2MI) is controlled via the inductive effect of isophorone diisocyanate, achieved through chemical capping. Subsequently, ICM-SU is produced by uniformly coating it with silica nanoparticles and a urea shell through mechano-fusion system’s dry processing for mechano-chemical capsuling, effectively isolating it from contact with epoxy. The curing mechanism and chemical structure of ICM-SU are identified in four stages: de-capping, de-shelling, formation of epoxy-imidazole adducts, and chain growth. Notably, the melting point of the urea shell (122 °C) closely matches the curing onset temperature, suggesting that the exposure of epoxy to restored 2MI initiates the curing process. As a result, ICM-SU demonstrates significantly enhances storage stability at 20 °C for over 42 days, a stark improvement over 2MI, which solidifies within 8 h. Moreover, specimens cured with ICM-SU exhibits a 32 % increase in tensile strength and a 25 % improvement in Young’s modulus compared to those cured with 2MI, attributed to the reinforcing filler effect of silica nanoparticles.

Nanometer-Scale Tunable mesopores in silica fillers for Facile enhancement of epoxy adhesion

Epoxy resins are essential polymeric materials for various industrial applications owing to their excellent adhesion, thermal properties, and processability. Reported improvement methods for overcoming the limitations of epoxy-resin adhesives involve incorporating fillers such as silica, clay, carbon nanotubes, and graphene. While silica nanoparticles are commonly used in industrial applications, their properties often require enhancement. In this study, mesoporous silica nanoparticles (MSNs) were synthesized using cetyltrimethylammonium bromide and novel swelling agents, 2,6-dihydroxybenzoic acid and decane, to control pore sizes within the 2–4 nm range. Transmission electron microscope and nitrogen adsorption analyses confirmed pore sizes of 2.0, 3.1, and 3.9 nm. Applying MSNs as nanofillers to epoxy resin adhesive resulted in enhanced adhesive properties with increasing pore size, particularly with 0.5 wt% MSN-4 nm, achieving a 51.4 % improvement in shear strength compared to that of bare epoxy resin. This enhancement is attributed to the increased specific surface area of the MSNs, providing more interaction sites with the epoxy resin and improving resin penetration and interaction. These findings highlight the critical role of nanopore size in optimizing adhesion in nanofiller applications and emphasize the potential of MSNs as superior nanofillers for future industrial applications.

Nanosilica/recycled polycarbonate composites for electronic packaging

Several simple methods were performed to recycle compact discs (CDs) using an alkaline solution. The hydrophilic silica nanoparticles were incorporated into the recycled deinked polycarbonate CDs, and these particles affected the dielectric, structure, and thermal properties of the recycled polycarbonates. The thermal properties of recycled CDs were studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). No significant change in the thermal stability of polycarbonate/silica nanocomposites was observed with the mechanical /chemical modifications. X-ray diffraction (XRD) revealed the structural aspects, showing a correlation between crystallinity, silica nanoparticles, and modification methods. The mechanically treated sample after chemical handling had the lowest degree of crystallinity (48%), showing that the modification methods enhanced the formation of the amorphous state, thus affecting its dielectric properties. Scanning electron microscopy (SEM) characterized the CD samples' microstructure and morphology. Finally, the dielectric properties were studied using broadband dielectric spectroscopy (BDS) in the 101 - 106 Hz range. The samples prepared using chemical and mechanical treatments were of low dielectric loss. This increases its importance when such samples are used as antistatic charge materials. For these reasons, recycled PC/SiO2 nanocomposites are recommended as effective packaging materials for electronic components.

Predicting tensile and fracture parameters in polypropylene-based nanocomposites using machine learning with sensitivity analysis and feature impact evaluation

This study examines the efficacy of decision tree and AdaBoost algorithms in predicting mechanical and fracture parameters of polypropylene nanocomposites toughened with ethylene-based and propylene-based thermoplastic elastomers and reinforced with fumed silica and halloysite nanotube nanoparticles. The essential work of the fracture approach was utilized to study the fracture parameters, including elastic and plastic works of the blended polymer nanocomposites. The data were divided into 80 % for training and 20 % for testing. AdaBoost consistently achieved superior performance compared to the decision tree model in all variables throughout both the training and testing stages. During the testing phase, the AdaBoost model obtained R2 values of 0.90 for Young's modulus, 0.93 for elongation at break, 0.87 for tensile strength, 0.86 for plastic work, and 0.60 for elastic work. Also, the mean absolute percentage error for the AdaBoost model during the test phase was 3.10 % for Young's modulus, 3.25 % for tensile strength, 10.34 % for elastic work, 13.55 % for plastic work, and 24.78 % for elongation at break. Furthermore, a sensitivity analysis examining the effects of various features such as TPO type, nanoparticles, and nanoparticle type on mechanical properties reveals that TPO has the most significant overall influence. The results also include an analysis of the impact of the key features on each mechanical property based on the sensitivity analysis.