Search Results (406)

Galactomannan/organomodified montmoriollonite (G₁M/OM-MMT) nanocomposites and G₂M/OM-MMT nanocomposites were biosynthesized using galactomannan (GM) and organomodified montmorillonite (OM-MMT) with cetyltrimethylammonium bromide (CTAB, 10⁻² M) designed for antioxidant activities. Furthermore, galactomannan (GM) was isolated from fruit rind of Punica granatum grown in the Djelfa region, in Algeria, and the nanoclay used in this work was an Algerian montmorillonite. Two different types of nanocomposites were synthetized using different amounts of GM and OM-MMT (w/w) [GM₁/OM-MMT (0.5:1) and GM₂/OM-MMT (0.5:2)] via a solution interaction method. FTIR analysis confirmed the intercalation of GM in the interlayer of OM-MMT. Moreover, X-ray diffraction (XRD) showed that the interlayer space of OM-MMT was increased from 124.6 nm to 209.9 nm, and regarding the intercalation of GM in the OM-MMT interlayers, scanning electron microscopy (SEM) and energy-dispersive X-ray (DEX) confirmed the intercalated structure of the nanocomposites, while thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) improved the thermal stability of the synthesized bionanocomposites. The antioxidant activities of the GM₁/OM-MMT nanocomposites and GM₂/OM-MMT nanocomposites were evaluated with a spectrophotometer and DPPH (1,1-diphenyl-2-picrylhydrazine) radical scavenging assay. GM₁/OM-MMT nanocomposites and GM₂/OM-MMT nanocomposites gave good antioxidant activity. Indeed, GM₁/OM-MMT had an IC₅₀ of 0.19 mg/mL and GM₂/OM-MMT an IC₅₀ of 0.28 mg/mL. Full article

Concrete usage is increasing rapidly; subsequently, the industry’s carbon footprint is increasing and impacting the environment significantly. Large amounts of fine and coarse aggregate, including cement, are needed to fulfill the increased demand, leading to increased natural aggregate usage. Therefore, finding a fine aggregate replacement in concrete is essential. Coal bottom ash (CBA) and coal boiler slag (CBS), byproducts of coal-burning power plants with pozzolanic properties, can replace fine aggregate in concrete to reduce global natural material depletion, health hazards, and technical and economic problems associated with power plants’ solid waste. This study was conducted to determine the optimum fine aggregate replacement amount of CBA and CBS in concrete while improving concrete performance. The optimum CBA and CBS content is 50%, which reduces fine aggregate usage in a concrete mix by 50% while maintaining equivalent or better concrete strength than the control. The optimum CBA content has a unit weight lower than the control for all mixes tested in this study, which makes the CBA mix lightweight concrete. The optimum CBA concrete has 15%, 43%, and 42% higher compressive strength than the control after 7 days, 28 days, and 56 days of curing, respectively. On the other hand, the optimum CBS concrete has 12%,16%, and 16% increased compressive strength than the control after 7, 28, and 56 days of curing, respectively. The compressive strength of optimum CBA concrete was higher than the optimum CBS, indicating that CBA concrete yields higher compressive strength than CBS, possibly due to the difference in physical properties, water absorption capacity, and bulk density. Nanoclay increased CBA concrete compressive strength at an early stage and increased the optimum content to 80% CBA. Therefore, using CBA and CBS can significantly reduce natural material usage and environmental harm by reducing CBA waste disposal and improving concrete performance. Full article

This research follows the principles of circular economy through the zero waste concept and cascade approach performed in two steps. Our paper focuses on the first step and explores the characteristics of developed biocomposite materials made from a biodegradable poly(lactic acid) polymer (PLA) reinforced with natural fibers isolated from the second generation of biomass (agricultural biomass and weeds). Two plants, Spartium junceum L. (SJL) and Sida hermaphrodita (SH), were applied. To enhance their mechanical, thermal, and antimicrobial properties, their modification was performed with environmentally friendly additives—linseed oil (LO), organo-modified montmorillonite nanoclay (MMT), milled cork (MC), and zinc oxide (ZnO). The results revealed that SH fibers exhibited 38.92% higher tensile strength than SJL fibers. Composites reinforced with SH fibers modified only with LO displayed a 27.33% increase in tensile strength compared to neat PLA. The addition of LO improved the thermal stability of both biocomposites by approximately 5–7 °C. Furthermore, the inclusion of MMT filler significantly reduced the flammability, lowering the heat release rate to 30.25%, and enabling the categorization of developed biocomposite in a group of flame retardants. In the second step, all waste streams generated during the fibers extraction process are repurposed into the production of solid biofuels (pellets, briquettes) or biogas (bio)methane. Full article

Stimuli-responsive hydrogels hold immense promise for biomedical applications, but conventional gelation processes often struggle to achieve the precision and complexity required for advanced functionalities such as soft robotics, targeted drug delivery, and tissue engineering. This study introduces a class of 3D-printable magnetic hydrogels with tunable stiffness, adhesion, and magnetic responsiveness, prepared through a simple and efficient “one-pot” method. This approach enables precise control over the hydrogel’s mechanical properties, with an elastic modulus ranging from 43 kPa to 277 kPa, tensile strength from 93 kPa to 421 kPa, and toughness from 243 kJ/m³ to 1400 kJ/m³, achieved by modulating the concentrations of acrylamide (AM) and Fe₃O₄ nanoparticles. These hydrogels exhibit rapid heating under an alternating magnetic field, reaching 44.4 °C within 600 s at 15 wt%, demonstrating the potential for use in mild magnetic hyperthermia. Furthermore, the integration of Fe₃O₄ nanoparticles and nanoclay into the AM precursor optimizes the rheological properties and ensures high printability, enabling the fabrication of complex, high-fidelity structures through extrusion-based 3D printing. Compared to existing magnetic hydrogels, our 3D-printable platform uniquely combines adjustable mechanical properties, strong adhesion, and multifunctionality, offering enhanced capabilities for use in magnetic actuation and hyperthermia in biomedical applications. This advancement marks a significant step toward the scalable production of next-generation intelligent hydrogels for precision medicine and bioengineering. Full article

This study discusses the tribological characteristics of Polyvinylidene Fluoride (PVDF)/nanoclay composites, focusing on the effects of nanoclay content (0, 1, 2 and 3 wt.%), load, sliding speed, and sliding distance on the wear rate, friction coefficient, specific wear rate, and temperature. A Taguchi Design of Experiments technique was applied to optimize and assess these aspects. The results demonstrated that nanoclay addition considerably improved the wear resistance and frictional stability of the PVDF composites. Specifically, a nanoclay concentration of 3 wt.% gave the lowest wear rate (0.05 mg/m) with a 10 N load and 100 m sliding distance, lowering wear by roughly 23% compared to unreinforced PVDF. The friction coefficient was similarly lowered by 12% with 3 wt.% nanoclay, reaching a value of 0.38 at the highest load of 40 N. Interaction effects demonstrate that load and sliding distance are key elements impacting wear performance, with large loads and long distances virtually tripling the wear rate. ANOVA results quantify nanoclay’s contribution to a wear rate reduction of 51.29%, whereas load and sliding distance contributed 22.47% and 16.98%, respectively. Temperature increases due to frictional heating reached 10 °C under rigorous test conditions, although nanoclay treatment decreased this increase by an average of 15%. Characterization by XRD and FTIR verified the nanoclay dispersion inside the PVDF matrix, whereas the SEM images demonstrated smoother surfaces and fewer wear tracks in the nanoclay-reinforced samples. These findings illustrate the efficiency of nanoclay in increasing the wear resistance of PVDF, making these composites appropriate for high-performance applications. This research provides useful insights into enhancing PVDF/nanoclay composites, with possible uses in situations that demand endurance and thermal stability. Full article

The objective of the present work was to prepare hybrid epoxy composites with improved mechanical and thermal properties. The simultaneous use of two different modifiers in an epoxy resin was motivated by the expected occurrence of synergistic effects on the performance properties of the matrix. Such a hybrid composite can be used in more severe conditions and/or in broader application areas. Hybrid epoxy composites were prepared with polyurethane (PUR), Nanomer nanoclay and carbon nanotubes (CNT), followed by the evaluation of their mechanical and thermal properties. Synergistic improvements in mechanical properties of hybrid composites were observed for 0.5 wt% Nanomer and 1 wt% carbon nanotubes (CNT), 7.5 wt% PUR and 1 wt% CNT, and 5 wt% PUR and 1 wt% CNT, confirming the occurrence of synergistic effects as to the impact strength (IS) of the matrices, compared to binary systems. The toughening induced by CNT/Nanomer modifiers can be attributed to the specific interfacial interactions between the two nanoparticles, while in the case of CNT/PUR, it can be explained by the combined effects of flexible polymer chains and the specific arrangement of nanoparticles in epoxy systems. Spectroscopy analysis confirmed the occurrence of interaction between OH groups in the epoxy matrix with CNT and reactive groups of PUR. The fracture surface showed plastic deformations, with good dispersion of CNT, explaining the improved mechanical properties of the matrix composites. Full article

In this study, reinforced thermoplastic nanoclay particle composites were prepared and used as filaments for additive manufacturing of specimens by using fused filament fabrication (FFF). Acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA) were used as thermoplastic polymer matrices. The particle reinforced composite feedstock filaments were fabricated from ABS and PLA pellets with different contents of nanoclay particles in a twin-screw extruder. Tensile and impact tests were carried out to evaluate the mechanical properties of the composite specimens fabricated by FFF. The mechanical test results showed an increase in the tensile strength of ABS matrix composites, but a decrease in the impact strength. For the case of PLA matrix composites, the tensile strength decreased when introducing the nanoclay particles and only with 3% of nanoclay particles was an increase of impact strength observed. Successful additive manufacturing of the particle-reinforced composite was achieved. Full article

Three-dimensional printing technology is transforming the construction industry, which is increasingly turning to advanced materials and techniques to meet environmental and economic challenges. This comprehensive literature review evaluated various binder materials, including cement, geopolymers, earthen materials, supplementary cementitious materials, polymers, and biopolymers, with a focus on their environmental impacts and rheological properties. The study revealed an increasing interest in cementitious binders, which deliver essential structural strength and exhibit a wide range of yield stress values (15 to 6500 Pa), influenced by binder type and supplementary materials such as nanoclay. However, the significant CO₂ emissions associated with cement pose major sustainability challenges. As a sustainable alternative, geopolymers demonstrate lower yield stress values (800 to 3000 Pa) while ensuring adequate buildability for vertical printing and reducing environmental impact. These findings underscore the need to adopt sustainable binder matrices to align 3D printing construction practices with global sustainability goals. Full article

This review provides a comprehensive exploration of the current research landscape surrounding nanoclay-reinforced epoxy composites. A primary challenge in developing these nanocomposites is the hydrophilic nature of pristine clay, which hinders its dispersion within the epoxy matrix. To address this issue, organic modifiers are frequently employed to enhance clay compatibility and facilitate effective incorporation into the nanocomposite structure. The unique properties of nanoclay make it a particularly attractive reinforcement material. The performance of nanoclay/epoxy nanocomposites is largely determined by their morphology, which is influenced by various factors including processing methods, clay types, modifiers, and curing agents. A thorough understanding and control of these parameters are essential for optimizing nanocomposite performance. These advanced materials find extensive applications across multiple industries, including aerospace, defense, anti-corrosive coatings, automotive, and packaging. This review offers an in-depth analysis of the processing techniques, mechanical properties, barrier capabilities, and thermal characteristics of nanoclay-reinforced epoxy nanocomposites. Additionally, it explores their diverse industrial applications, providing a holistic view of their potential and current use. By examining the multifaceted landscape of epoxy/clay nanocomposites, this review illuminates the intricate relationships between fabrication methods, resulting properties, and potential industrial applications. It serves as a comprehensive resource for researchers and practitioners seeking to advance the development and application of these innovative materials. Full article

Although a lot of recent research revealed advantages of novel biopolymers’ implementation as active food packaging polymers, there is not an equivalent effort from industry to use such films, probably because of the required cost to change the supply chain and the equipment. This study investigates the use of two natural abundant nanoclays, laponite (Lap) and montmorillonite (Mt), as eugenol slow-release carriers for enhancing the functionality of low-density polyethylene (LDPE) active packaging films. The target is to combine the spirit of the circular economy with the existent technology and the broadly used materials to develop a novel attractive product for active food packaging applications. Utilizing a vacuum-assisted adsorption method, eugenol was successfully intercalated into Lap and Mt nanoclays, forming EG@Lap and EG@Mt nanohybrids. Testing results confirmed effective integration and dispersion of the nanohybrids within the LDPE matrix. The most promising final film seems to be the LDPE with 15% w/w EG@Lap nanohybrid which exhibited a higher release rate (k₂ = 5.29 × 10⁻⁴ s⁻¹) for temperatures ≤70 °C, similar mechanical properties, a significantly improved water barrier (D_wv = 11.7 × 10⁻⁵ cm²·s⁻¹), and a slightly improved oxygen barrier (Pe_O2 = 2.03 × 10⁻⁸ cm²·s⁻¹) compared with neat LDPE. Antimicrobial and sensory tests on fresh minced pork showed two days’ shelf-life extension compared to pure LDPE and one more day compared to LDPE with 15% w/w EG@Mt nanohybrid. Full article

This study presents the synthesis, characterization, and evaluation of hybrid hydrogels based on calcium alginate (Ca-Alg) and synthetic nanoclay LaponiteRD (Lap), with an emphasis on their swelling and sorption properties. The motivation behind the development of these hybrid hydrogels stems from the need for sustainable materials with enhanced mechanical strength, swelling properties, and sorption capacity for environmental remediation and controlled-release applications. Synthesis methods for the ionotropically cross-linked Ca-Alg hydrogel and Alg–Lap composite hydrogels, based on Alg and Lap in the form of granules and fibres, have been developed. The Fourier-transform infrared spectroscopy (FTIR), Energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD) analyses of composite hydrogels confirmed the successful incorporation of Lap into the Ca-Alg matrix, indicating strong interactions between the polymer and clay, which enhanced the structural integrity of the hydrogels. The morphology of the surface and pore structure of nanocomposites were studied using Scanning Electron Microscopy (SEM). The swelling behaviour of the nanocomposites was largely dependent on the concentrations of Lap and the cross-linking agent (CaCl₂), with higher concentrations leading to more rigid, less swellable structures due to the increased cross-linking density. The sorption studies, specifically with Fe(II) ions, demonstrated that the hybrid hydrogels possess a large sorption capacity, with Lap contributing to selective sorption at lower Fe(II) ion concentrations and Alg enhancing overall capacity at higher concentrations. This suggests that the synergistic interaction between Alg and Lap not only improves mechanical stability but also tailors the sorption properties of the hydrogels. These findings position the Alg-Lap hydrogels as promising materials for a range of environmental applications, including wastewater treatment, heavy metal ion removal, and the design of advanced filtration systems. The study’s insights into the tunability of these hydrogels pave the way for further research into their use in diverse fields such as biomedicine, agriculture, and industrial water management. Full article

Cement-based 3D printing provides an opportunity to create cement-based elements with a hierarchy of structures and patterns that are not easily achievable using traditional casting techniques, thereby providing new possibilities for improving thermal control and energy storage in cement-based materials. In this study, the influence of internal architecture and ink formulation on the thermal behavior of 3D-printed cement composite beams was investigated using infrared thermal imaging and a conceptual one-dimensional heat transfer model based on cooling fins in convective media. Three-dimensional printed beams with rectilinear, three-dimensional honeycomb, and Archimedean chord infill patterns and cement ink formulations with and without 5% halloysite nanoclay were exposed to a heating source at one end. The thermal behavior of the beams was found to be predominantly influenced by their internal architecture rather than the cement ink formulation, with differences in void structures and heat transfer pathways among the different architectures resulting in a hierarchy of apparent thermal conductivity. The internal architecture resulted in a reduction in apparent thermal conductivity by up to 75%, while the incorporation of halloysite nanoclay in the cement ink led to a reduction of up to 14%. Among the tested internal architecture, the rectilinear architecture showed a 10–15% higher apparent thermal conductivity compared to the three-dimensional honeycomb architecture and a 35–40% higher apparent thermal conductivity than the Archimedean architecture. The research demonstrates a promising strategy for fabricating and evaluating cement-based materials with thermal management capabilities using 3D printing methods. Full article

The growing demand for products made of polymeric materials, including the commonly used polypropylene (PP), is accompanied by the problem of storing and disposing of non-biodegradable waste, increasing greenhouse gas emissions, climate change and the creation of toxic products that constitute a health hazard of all living organisms. Moreover, most of the synthetic polymers used are made from petrochemical feedstocks from non-renewable resources. The use of petrochemical raw materials also causes degradation of the natural environment. A potential solution to these problems is the use of biopolymers. Biopolymers include biodegradable or biosynthesizable polymers, i.e., obtained from renewable sources or produced synthetically but from raw materials of natural origin. One of them is the poly(3-hydroxybutyrate) (P3HB) biopolymer, whose properties are comparable to PP. Unfortunately, it is necessary to modify its properties to improve its processing and operational properties. In the work, hybrid polymer nanobiocomposites based on P3HB, with the addition of chain, uncross-linked polyurethane (PU) and layered aluminosilicate modified with organic salts (Cloisite^®30B) were produced by extrusion process. The introduction of PU and Cloisite^®30B to the polymer matrix (P3HB) influenced the processing parameters beneficially and resulted in a decrease in the extrusion temperature of more than 10 °C. The influence of the simultaneous addition of a constant amount of PU (10 m/m%) and the different amounts of nanoadditives (1, 2 and 3 m/m%) on the compatibility, morphology and static mechanical properties of the resulted nanobiocomposites were examined. The component interactions by Fourier transformation infrared spectroscopy (FTIR) analysis, nano- and microscale structure studies using small-angle X-ray scattering (SAXS) and morphology by scanning electron microscopy (SEM) were carried out, and the hardness and tensile strength of the obtained polymer nanobiocomposites were determined. FTIR analysis identified the compatibility of the polyester matrix, PU, and organomodified montmorillonite, the greatest being 3 m/m% Cloisite30B content. The addition of PU to the polyester elasticizes the material and decreases the material’s strength and ductility. The presence of nanoclay enhanced the mechanical properties of nanobiocomposites. The resulting nanobiocomposites can be used in the production of short-life materials applied in gardening or agriculture. Full article

Currently, postulated trends and law regulations tend to direct polymer technology toward sustainability and environmentally friendly solutions. These approaches are expressed by keeping materials in a loop aimed at the circular economy and by reducing the environmental burdens related to the production and use of polymers and polymer-based materials. The application of recycled or waste-based materials often deals efficiently with the first issue but at the expense of the final products’ performance, which requires various additives, often synthetic and petroleum-based, with limited sustainability. Therefore, a significant portion of research is often required to address the drawbacks induced by the application of secondary raw materials. Herein, the presented study aimed to investigate the fire performance of polymer composites containing highly flammable matrix polyurethane (PU) foam and filler ground tire rubber (GTR) originating from car tire recycling. Due to the nature of both phases and potential applications in the construction and building or automotive sectors, the flammability of these composites should be reduced. Nevertheless, this issue has hardly been analyzed in literature and dominantly in our previous works. Herein, the presented work provided the next step and investigated the input of nanoclays to the synergistic flammability reduction in flexible, foamed PU/GTR composites. Hybrid compositions of organophosphorus FRs with expandable graphite (EG) in varying proportions and with the addition of surface-modified nanoclays were examined. Changes in the parameters obtained during cone calorimeter tests were determined, discussed, and evaluated with the fire performance index and flame retardancy index, two parameters whose goal is to quantify the overall fire performance of polymer-based materials. Full article

This paper presents the obtaining and characterization of blends based on high-density polyethylene (HDPE) and plasticized starch. In addition to plasticized starch (28.8% w/w), the compositions made also contained other ingredients, such as polyethylene-graft-maleic anhydride as a compatibilizer, ethylene propylene terpolymer elastomer, cross-linking agents, and nanoclay. Plasticized starch contains 68.6% w/w potato starch, 29.4% w/w glycerin, and 2% w/w anhydrous citric acid. Blends based on HDPE and plasticized starch were made in a Brabender Plasti-Corder internal mixer at 160 °C, and plates for testing were obtained using the compression method. Thermal analyses indicate an increase in the crystallization degree of the HDPE after the addition of plasticized starch. SEM micrographs indicate that blends are compatibilized, with the plasticized starch being well dispersed as droplets in the HDPE matrix. Samples show high hardness values (62–65° ShD), good tensile strength values (14.88–17.02 N/mm²), and Charpy impact strength values (1.08–2.27 kJ/m² on notched samples, and 7.96–20.29 kJ/m² on unnotched samples). After 72 h of water immersion at room temperature, mixtures containing a compatibilizer had a mass variation below 1% and water absorption values below 1.7%. Upon increasing the water immersion temperature to 80 °C, the sample without the compatibilizer showed a mass reduction of −2.23%, indicating the dissolution of the plasticized starch in the water. The samples containing the compatibilizer had a mass variation of max 8.33% and a water absorption of max 5.02%. After toluene immersion for 72 h at room temperature, mass variation was below 8%. Full article