Search Results (41)

As critical infrastructure for carbon capture, utilization, and storage (CCUS) and large-scale energy storage, subsurface salt caverns are seriously challenged by fluid-induced sediment mobilization during the supplementary debrining. Conventional bulk resin consolidation often causes severe viscous fingering, uneven consolidation, and pore clogging under hypersaline conditions. Here, we develop a foam-templated hybrid polymer gel co-stabilized by silica nanoparticles, polyvinyl alcohol, and the zwitterionic surfactant. The key novelty is the use of foam as a transient transport template that redistributes the resin phase and promotes selective cementation at grain-contact points instead of indiscriminate pore filling. This nano-reinforced gel system remained stable under hypersaline conditions (24% NaCl), and temperatures ranging from 20–80 °C. Micro-CT analysis showed that this selective templating preserved an interconnected pore network with a porosity above 45% and a CT-derived permeability of approximately 1.18 D, while reducing binder consumption by 55.6% relative to bulk resin injection. Crucially, a 1:200 geometrically scaled, velocity-matched pilot model demonstrated that this gel strategy limited sediment entrainment below 0.5% and reduced fluid discharge by 45.9%. These results establish a material-efficient consolidation strategy that combines sediment stabilization with permeability preservation, providing a promising solution for safer supplementary debrining in salt-cavern CCUS and energy-storage operations. Full article

Under the global carbon-neutrality target, the technology of carbon capture, utilization, and storage-enhanced oil recovery (CCUS-EOR) faces a severe challenge of carbonation-induced degradation of oil-well cement in harsh downhole environments. Traditional cement suffers serious structural failure under high-temperature and high-pressure CO₂ conditions, whereas single-nanoparticle or polymer modification cannot meet long-term safety requirements. Meanwhile, the comparative study between the “matrix modification strategy” and the “cement system replacement strategy” is still insufficient under real CCUS-EOR conditions. In this study, experimental investigations including macroscopic performance testing, phase analysis, and multi-scale microstructural characterization were conducted. This study systematically evaluates the carbonation resistance of polyaniline@titanium dioxide-modified cement (P@T) and calcium aluminate phosphate cement (CAP). The results show that the carbonation resistance follows the descending order: CAP > P@T > silica-fume-containing Class G oil-well cement (PT). CAP seems to demonstrate a potential “corrosion-induced densification” effect. After 90 days of corrosion, its compressive strength increases to 62.5 MPa, and its permeability decreases to 13.3% of the initial value, indicating continuously improved performance. P@T indicates the possible decoupling of high carbonation degree (CaCO₃ content of 25.26%) and microstructural stability through a structural regulation mechanism of “physical filling–homogeneous distribution of carbonation products”. In contrast, PT undergoes complete structural failure after 60 days. This study fills a gap in comparative evaluation between modification and replacement schemes, reveals the multi-scale structural regulatory effects of P@T and the intrinsic stability of CAP, and provides two reliable cement solutions—“modification enhancement” and “system replacement”—for CCUS-EOR environments. The scientific validity is demonstrated through multi-scale characterization, offering key theoretical and technical support for ensuring long-term wellbore integrity. Full article

A water-soluble hydroxypropyl cellulose (HPC) polymer matrix has been filled with different weight percentages (wt.%) of multiwalled carbon nanotubes (MWCNTs), fullerenes C₆₀, fullerenols C₆₀(OH)_24, and their combinations. We study the potential of the 0D nanoparticles for improving electrical properties of the conductive MWCNT network in a biocompatible matrix. Physicochemical effects of fillers content, both individually and in combinations (MWCNTs/C₆₀ and MWCNTs/C₆₀(OH)₂₄), for these composite systems, have been investigated. The performed SAXS analysis shows improved nanofiller dispersion for films with two fillers. The electrical percolation threshold (P_c) in MWCNTs composites occurs at ≈1.0 wt.%. A synergistic effect for binary filler composites on the electrical conductivity has been evaluated by keeping a constant amount of 0.5 wt.% MWCNTs (σ ≈ 3 × 10⁻⁹ S·m⁻¹) and increasing the amount of C₆₀ or C₆₀(OH)₂₄. A large increase in the electrical conductivity is obtained for the bifiller composites with 0.5 wt.% MWCNTs and 1.5 wt.% of C₆₀(OH)₂₄, reaching σ ≈ 0.008 S·m⁻¹. Further, the sensing properties of 4.0/1.0 MWCNT/C₆₀ nanocomposites were demonstrated by measuring both piezoresistive (PR) and thermoresistive (TR) responses. The combination of semiconductive fullerene/fullerenols combined with MWCNTs allows obtaining more homogeneous composites in comparison to single MWCNTs composites and also gives possibilities for tuning the electrical conductivity of the system. Overall, it is demonstrated that the use of bifillers with a water soluble biopolymeric matrix allows the development of eco-friendly high-performance electroactive materials for sustainable digitalization. Full article

As the volume of polymer waste continues to grow, the development of methods for their processing and the creation of composites is an urgent task. In this work, the characteristics of sand–polymer composites based on reclaimed thermoplastics (1:3 mixture of polyolefins) are investigated. It was found that composites containing up to 75 wt% silica sand (100–300 μm) retained acceptable compressive strength (at least 25 MPa) at a strain of no more than 5%. Sand surface treatment improved the interaction between polymer and filler, increasing compressive strength by 10–15% and impact strength by 10% at 70–75 wt% of filler. The deformation and strength parameters of composites modified with carbon nanocomponents were investigated. The dependencies of compressive and bending strength on technological parameters of formation were obtained. The role of modifying components in appretization and reinforcement was shown. The introduction of technological lubricants improved homogeneity but reduced strength. The strengthening effect was related to the increase in the proportion of polymer interacting with the filler surface when the thickness of the polymer matrix reached the nanostate. The introduction of silica nanoparticles (up to 0.1 wt%) increased the compressive strength by 15%. However, the decrease in melt fluidity limited the degree of filling. The obtained composites are promising for application as structural materials in hull products used in limited climatic conditions. Full article

Bisphenol A (BPA) is an industrial chemical used primarily in the manufacture of polycarbonate plastics and epoxy resins. BPA is considered an endocrine-disrupting chemical (EDC) because it interferes with hormonal systems. Over the decades, several techniques have been proposed for BPA removal in wastewaters. This study discusses recent advancements and progress of effective techniques for BPA removal, including membrane, adsorption, advanced oxidation process (AOPs), and biodegradation. The mechanisms of BPA adsorption on modified adsorbents include pore-filling, hydrophobic interactions, hydrogen bonding, and electrostatic interactions. Among the various agricultural waste adsorbents, Argan nut shell-microporous carbon (ANS@H20–120) exhibited the highest efficiency in removing BPA. Furthermore, the performance of magnetic treatment for activated carbon (AC) regeneration is introduced. According to the present study, researchers should prioritize agricultural waste-based adsorbents such as ACs, highly microporous carbons, nanoparticles, and polymers for the removal of BPA. In particular, the combination of adsorption and AOPs (advanced oxidations) is regarded as an efficient method for BPA removal. A series of relevant studies should be conducted at laboratory, pilot, and industrial scales for optimizing the application of agricultural waste-based AC to reduce BPA or other refractory pollutants from an aqueous environment. Full article

Multifunctional polymer composites containing micro/nano hybrid reinforcements have attracted intensive attention in the field of materials science and engineering. This paper develops a multi-phase analytical model for investigating the effective electrical conductivity of micro-silicon carbide (SiC) whisker/nano-carbon black (CB) polymer composites. First, CB nanoparticles are dispersed within the non-conducting epoxy to achieve a conductive CB-filled nanocomposite and its electrical conductivity is predicted. Some critical microstructures such as volume percentage and size of nanoparticles, and interphase characteristics surrounding the CB are micromechanically captured. Next, the electrical conductivity of randomly oriented SiC-containing composites in which the nanocomposite and whisker are considered as the matrix and reinforcement phases, respectively, is estimated. Influences of whisker aspect ratio and volume fraction on the effective electrical conductivity of the SiC/CB-containing polymer composites are explored. Some comparison studies are performed to validate the accuracy of the model. It is observed before the percolation threshold that the addition of nanoparticles with a uniform dispersion can improve the electrical conductivity of the polymer composites containing SiC/CB hybrids. Moreover, the results show that the electrical conductivity is more enhanced by the decrease in nanoparticle size. Interestingly, the composite percolation threshold is significantly reduced when SiC whiskers with a higher aspect ratio are added. This work will be favorable for the design of electro-conductive polymer composites with high performances. Full article

Conductive polymer composites (CPCs), obtained by incorporating conductive fillers into a polymer matrix, are suitable for producing strain sensors for structural health monitoring (SHM) in infrastructure. Here, the effect of the addition of inorganic semiconductor nanoparticles (INPs) to a poly (vinylidene fluoride) (PVDF) composite filled with multi-walled carbon nanotubes (MWCNTs) on the piezoresistive behavior is investigated. INPs with different morphologies and sizes are synthesized by a hydrothermal method. The added inorganic oxide semiconductors showed two distinct morphologies, including different phases. While particles with flower-like plate morphology contain phases of orth-ZnSnO₃ and SnO, the cauliflower-like nanoparticles contain these metal oxides and ZnO. The nanoparticles are characterized by field-emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD), and the nanocomposites by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). Cyclic tensile testing is applied to determine the strain-sensing behavior of PVDF/1 wt% MWCNT nanocomposites with 0–10 wt% inorganic nanoparticles. Compared to the PVDF/1 wt% MWCNT nanocomposite, the piezoresistive sensitivity is higher after the addition of both types of nanoparticles and increases with their amount. Thereby, nanoparticles with flower-like plate structures improve strain sensing behavior slightly more than nanoparticles with cauliflower-like structures. The thermogravimetric analysis results showed that the morphology of the semiconductor nanoparticles added to the PVDF/MWCNT matrix influences the changes in thermal properties. Full article

Polymer nanocomposites filled with carbon nanoparticles (CNPs) are a hot topic in materials science. This article discusses the current research on the use of these materials as interfacial electron transfer films for solid contact potentiometric membrane sensors (SC-PMSs). The results of a comparative study of plasticized poly (vinyl chloride) (pPVC) matrices modified with single-walled carbon nanotubes (SWCNTs), fullerenes-C60, and their hybrid ensemble (SWCNTs-C60) are reported. The morphological characteristics and electrical conductivity of the prepared nanostructured composite films are reported. It was found that the specific electrical conductivity of the pPVC/SWCNTs-C60 polymer film was higher than that of pPVC filled with individual nanocomponents. The effectiveness of this composite material as an electron transfer film in a new potentiometric membrane sensor for detecting phenylpyruvic acid (in anionic form) was demonstrated. Screening for this metabolic product of phenylalanine in body fluids is of significant diagnostic interest in phenylketonuria (dementia), viral hepatitis, and alcoholism. The developed sensor showed a stable and fast Nernstian response for phenylpyruvate ions in aqueous solutions over the wide linear concentration range of 5 × 10⁻⁷–1 × 10⁻³ M, with a detection limit of 10^−7.2 M. Full article

Cancer is one of the deadliest diseases worldwide and has been responsible for millions of deaths. However, developing a satisfactory smart multifunctional material combining different strategies to kill cancer cells poses a challenge. This work aims at filling this gap by developing a composite material for cancer treatment through hyperthermia and drug release. With this purpose, magnetic nanoparticles were coated with a polymer matrix consisting of poly (L-co-D,L lactic acid-co-trimethylene carbonate) and a poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide) triblock copolymer. High-resolution transmission electron microscopy and selected area electron diffraction confirmed magnetite to be the only iron oxide in the sample. Cytotoxicity and heat release assays on the hybrid nanoparticles were performed here for the first time. The heat induction results indicate that these new magnetic hybrid nanoparticles are capable of increasing the temperature by more than 5 °C, the minimal temperature rise required for being effectively used in hyperthermia treatments. The biocompatibility assays conducted under different concentrations, in the presence and in the absence of an external alternating current magnetic field, did not reveal any cytotoxicity. Therefore, the overall results indicate that the investigated hybrid nanoparticles have a great potential to be used as carrier systems for cancer treatment by hyperthermia. Full article

The subject of the present work is the synthesis and analysis of the structural and morphological properties of Ag-containing carbon composites and the investigation of their practical application in water purification and disinfection. A series of composites were synthesized by carbonization of resorcinol–formaldehyde polymers filled with Ag-containing fumed silica under an inert atmosphere at 800 °C. The as-synthesized micro- and mesoporous carbon composites were characterized by their specific surface area of 466–529 m²/g. The suitability of the composites for flow-through filters was evaluated by kinetic studies on the adsorption of 4-chlorophenol. The composite with the highest amount of metallic nanophase showed the most effective kinetics with a rate constant (log k) and half-life (t_0.5) of −2.07 and 81 min, respectively. The antimicrobial susceptibility was determined against Gram-positive (Staphylococcus aureus ATCC 25923) and Gram-negative strains (Escherichia coli ATCC 25922, Klebsiella pneumoniae ATCC 700603, Pseudomonas aeruginosa ATCC 27853, and Acinetobacter baumannii ATCC 19606). The zones of bacterial growth inhibition correlated with the silver nanoparticle content and were the lowest for RFC-02 (10–12 mm) and the highest for the RFC-1 composite (15–16 mm), resulting from the increase in number of evenly distributed small Ag nanoparticles (3–5 nm) in the samples. Full article

The objective of this research was to develop highly effective conductive polymer composite (CPC) materials for flexible piezoresistive sensors, utilizing hollow three-dimensional graphitic shells as a highly conductive particulate component. Polystyrene (PS), a cost-effective and robust polymer widely used in various applications such as household appliances, electronics, automotive parts, packaging, and thermal insulation materials, was chosen as the polymer matrix. The hollow spherical three-dimensional graphitic shells (GS) were synthesized through chemical vapor deposition (CVD) with magnesium oxide (MgO) nanoparticles serving as a support, which was removed post-synthesis and employed as the conductive filler. Commercial multi-walled carbon nanotubes (CNTs) were used as a reference one-dimensional graphene material. The main focus of this study was to investigate the impact of the GS on the piezoresistive response of carbon/polymer composite thin films. The distribution and arrangement of GS and CNTs in the polymer matrix were analyzed using techniques such as X-ray diffraction and scanning electron microscopy, while the electrical, thermal, and mechanical properties of the composites were also evaluated. The results revealed that the PS composite films filled with GS exhibited a more pronounced piezoresistive response as compared to the CNT-based composites, despite their lower mechanical and thermal performance. Full article

The emergence of additive manufacturing technologies has brought about a significant transformation in several industries. Among these technologies, Fused Deposition Modeling/Fused Filament Fabrication (FDM/FFF) 3D printing has gained prominence as a rapid prototyping and small-scale production technique. The potential of FDM/FFF for applications that require improved mechanical, thermal, and electrical properties has been restricted due to the limited range of materials that are suitable for this process. This study explores the integration of various reinforcements, including carbon fibers, glass fibers, and nanoparticles, into the polymer matrix of FDM/FFF filaments. The utilization of advanced materials for reinforcing the filaments has led to the enhancement in mechanical strength, stiffness, and toughness of the 3D-printed parts in comparison to their pure polymer counterparts. Furthermore, the incorporation of fillers facilitates improved thermal conductivity, electrical conductivity, and flame retardancy, thereby broadening the scope of potential applications for FDM/FFF 3D-printed components. Additionally, the article underscores the difficulties linked with the utilization of filled filaments in FDM/FFF 3D printing, including but not limited to filament extrusion stability, nozzle clogging, and interfacial adhesion between the reinforcement and matrix. Ultimately, a variety of pragmatic implementations are showcased, wherein filled filaments have exhibited noteworthy benefits in comparison to standard FDM/FFF raw materials. The aforementioned applications encompass a wide range of industries, such as aerospace, automotive, medical, electronics, and tooling. The article explores the possibility of future progress and the incorporation of innovative reinforcement materials. It presents a plan for the ongoing growth and application of advanced composite materials in FDM/FFF 3D printing. Full article

Soft strain sensors based on conductive polymer composites (CPCs) provide a simple and feasible detection tool in wearable electronics, soft machines, electronic skin, etc. However, the CPCs-based soft strain sensors exhibit resistive viscoelasticity (or time-dependent properties) that hinder the intuitive reflection of the accurate strain and a simple calibration process. In this paper, CPCs with different carbon nanotubes (CNTs) and carbon black (CB) contents were prepared, and electro-mechanical experiments were conducted to study the effect of filler dimensionality and content on the resistive viscoelasticity of CPCs, aimed at guiding the fabrication of CPCs with low resistive viscoelasticity. Furthermore, resistive viscoelasticity and mechanical viscoelasticity were compared to study the origin of the resistive viscoelasticity of CPCs. We found that, at the vicinity of their percolation threshold, the CPCs exhibit high resistive viscoelasticity despite their high sensitivity. In addition, the secondary peaks for CB/SR composite were negligible when the CB concentration was low. Generally, compared with one-dimensional CNT-filled CPCs, the zero-dimensional CB-filled CPCs show higher sensitivity, lower resistive hysteresis, lower resistance relaxation ratio, and better cyclic performance, so they are more suitable for sensor usage. By comparing the resistive viscoelasticity and mechanical viscoelasticity of CPCs, it is indicated that, when the concentration of nanoparticles (NPs) approaches the percolation thresholds, the resistive viscoelasticity is mainly derived from the change of conductive network, while when the concentration of NPs is higher, it is primarily due to the unrecoverable deformations inside the material. Full article

Among nanocomposite materials, multifunctional polymer nanocomposites have prompted important innovations in the field of sensing technology. Polymer-based nanocomposites have been successfully utilized to design high-tech sensors. Thus, conductive, thermoplast, or elastomeric, as well as natural polymers have been applied. Carbon nanoparticles as well as inorganic nanoparticles, such as metal nanoparticles or metal oxides, have reinforced polymer matrices for sensor fabrication. The sensing features and performances rely on the interactions between the nanocomposites and analytes like gases, ions, chemicals, biological species, and others. The multifunctional nanocomposite-derived sensors possess superior durability, electrical conductivity, sensitivity, selectivity, and responsiveness, compared with neat polymers and other nanomaterials. Due to the importance of polymeric nanocomposite for sensors, this novel overview has been expanded, focusing on nanocomposites based on conductive/non-conductive polymers filled with the nanocarbon/inorganic nanofillers. To the best of our knowledge, this article is innovative in its framework and the literature covered regarding the design, features, physical properties, and the sensing potential of multifunctional nanomaterials. Explicitly, the nanocomposites have been assessed for their strain-sensing, gas-sensing, bio-sensing, and chemical-sensing applications. Here, analyte recognition by nanocomposite sensors have been found to rely on factors such as nanocomposite design, polymer type, nanofiller type, nanofiller content, matrix–nanofiller interactions, interface effects, and processing method used. In addition, the interactions between a nanocomposite and analyte molecules are defined by high sensitivity, selectivity, and response time, as well as the sensing mechanism of the sensors. All these factors have led to the high-tech sensing applications of advanced nanocomposite-based sensors. In the future, comprehensive attempts regarding the innovative design, sensing mechanism, and the performance of progressive multifunctional nanocomposites may lead to better the strain-sensing, gas/ion-sensing, and chemical-sensing of analyte species for technical purposes. Full article

The reinforcement of elastomers is essential in the rubber industry in order to obtain the properties required for commercial applications. The addition of active fillers in an elastomer usually leads to an improvement in the mechanical properties such as the elastic modulus and the rupture properties. Filled rubbers are also characterized by two specific behaviors related to energy dissipation known as the Payne and the Mullins effects. The Payne effect is related to non-linear viscoelastic behavior of the storage modulus while the Mullins or stress-softening effect is characterized by a lowering in the stress when the vulcanizate is extended a second time. Both effects are shown to strongly depend on the interfacial adhesion and filler dispersion. The basic mechanisms of reinforcement are first discussed in the case of conventional rubber composites filled with carbon black or silica usually present in the host matrix in the form of aggregates and agglomerates. The use of nanoscale fillers with isotropic or anisotropic morphologies is expected to yield much more improvement than that imparted by micron-scale fillers owing to the very large polymer–filler interface. This work reports some results obtained with three types of nanoparticles that can reinforce rubbery matrices: spherical, rod-shaped and layered fillers. Each type of particle is shown to impart to the host medium a specific reinforcement on account of its own structure and geometry. The novelty of this work is to emphasize the particular mechanical behavior of some systems filled with nanospherical particles such as in situ silica-filled poly(dimethylsiloxane) networks that display a strong polymer–filler interface and whose mechanical response is typical of double network elastomers. Additionally, the potential of carbon dots as a reinforcing filler for elastomeric materials is highlighted. Different results are reported on the reinforcement imparted by carbon nanotubes and graphenic materials that is far below their expected capability despite the development of various techniques intended to reduce particle aggregation and improve interfacial bonding with the host matrix. Full article