Properties Of Composites Research Articles

Enhancing Flame-Retardant Properties of Polyurethane Composites Using N-β-(Aminoethyl)-γ-aminopropyl Trimethoxysilane and Carbon Black Co-Modified Ammonium Polyphosphate

The search for a straightforward method to obtain efficient, affordable, and long-lasting flame retardants with both desirable flame-retardant and mechanical properties for polyurethane (PU) composites remains a significant challenge. In this study, the surface of ammonium polyphosphate (APP) was modified using N-β-(aminoethyl)-γ-aminopropyl trimethoxysilane (KH792) via an ion-exchange reaction, and the modified APP was coated with nanoscale carbon black (CB) to obtain CBAPP. CBAPP demonstrated good compatibility within the PU matrix and notably increased the tensile strength of the PU composites. Furthermore, CBAPP significantly enhanced the flame-retardant properties of the PU composites. The CBAPP/PU composite with a CBAPP mass fraction of 20% achieved a limiting oxygen index of 41.5% and a UL-94 class of V-0. According to the results of this study, our modification approach can be applied to develop other high-performance flame-retardant polymer-based composites, representing a significant contribution to the field of fire safety materials.

Enhanced morphological and thermal properties of epoxy composites reinforced with Palm and Prosopis Juliflora fibers

Abstract This study investigates the fabrication and characterization of a hybrid epoxy matrix composite reinforced with Palm and Prosopis Juliflora fibers fabricated using the hand layup technique. Three composite samples were prepared with varying weight percentages of palm and Prosopis Juliflora fiber reinforcements: 5% (Sample A), 10% (Sample B), and 15% (Sample C). Sample B having 10 weight percentage each of Palm fiber and Prosopis Juliflora fiber and 80 weight percentage of Epoxy matrix, exhibited superior performance with a tensile strength of 45.5 MPa and a hardness of 86.5 Shore D. Thermal analysis revealed Sample B’s exceptional thermal stability, with distinct decomposition stages observed through Thermogravimetric Analysis (TGA) and Differential Thermal Analysis (DTA). Void content analysis indicated Sample C had the lowest void content at 4.5%. Energy Dispersive x-ray (EDX) Analysis confirmed homogeneous fiber distribution and strong fiber-matrix adhesion, supported by carbon and oxygen peaks. Fourier-transform infrared spectroscopy (FTIR) spectra showed interactions between functional groups, including alcohols, carboxylic acids, and carbonyl compounds. These findings underscore the composite’s potential for high strength, toughness, and thermal stability applications.

Control of second-and third-order nonlinear optical properties of DCM and Znq2 composites fabricated by the physical vapor co-deposition process

In the present work, investigations on the second and third-order NLO properties of, 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM) reddye co-doped bis(8-hydroxyquinoline) Zinc (Znq2) thin films with different concentrations were investigated. The samples have a thickness of 100 nm. They were prepared using the physical vapor deposition (PVD) method under a high vacuum. The morphological properties were studied by atomic force microscopy. The second-order nonlinear susceptibility χ(2) after applying the corona poling technique was estimated using the comparative model of Lee, while the third-order nonlinear susceptibility χ(3) was estimated using the comparative model of Kubodera and Kobayashi. The tested samples varied in terms of the concentration of DCM in the structure, which visibly influenced their nonlinear response. The pure DCM thin film showed a large value of the second and third-order nonlinear susceptibility, while pure Znq2 had only the second harmonic response with a low value. In this study, we have demonstrated that doping with DCM, even with small concentrations, has also strongly enhanced the non-linearity of Znq2. The obtained results show that such compositions can be a good alternative for optoelectronic applications.

Investigations on the Mechanical, Morphological, and Thermal Degradation Properties of Alkali-Treated Polymer Composites Reinforced with an Areca Palm Leaf Stalk Fibers

Investigations on the Mechanical, Morphological, and Thermal Degradation Properties of Alkali-Treated Polymer Composites Reinforced with an Areca Palm Leaf Stalk Fibers

An In-depth Review on Argemone mexicana in the Management of Liver Health and Liver Cancer.

Argemone mexicana, commonly known as the Mexican prickly poppy, has been historically employed in traditional medicine for various ailments, including liver disorders. Given the rising prevalence of liver diseases, including cancer, investigating the potential efficacy of Argemone mexicana in promoting liver health is of paramount importance. This review aims to provide a comprehensive analysis of the existing literature on the hepatoprotective and anticancer properties of Argemone mexicana. A systematic literature search was conducted across PubMed, Google Scholar, and relevant botanical and pharmacological databases. Studies from various sources, including in vitro experiments, animal models, and clinical trials, were included in the review. The search focused on articles published up to 2010-2023, encompassing research that explored the botanical characteristics, chemical composition, traditional uses, and pharmacological properties of Argemone mexicana, specifically emphasizing its impact on liver health and cancer. The review revealed a wealth of studies highlighting the diverse pharmacological properties of Argemone mexicana. The botanical composition includes compounds with antioxidant and anti-inflammatory potential, suggesting hepatoprotective effects. Studies using in vitro and in vivo models demonstrated promising outcomes regarding liver function improvement and inhibition of liver cancer cell proliferation. While some clinical studies supported the traditional uses of Argemone mexicana, further well-designed trials are warranted to establish its clinical efficacy. In conclusion, Argemone mexicana shows promise as a natural agent for promoting liver health and combating liver cancer. Bioactive compounds with antioxidant and anti-inflammatory properties suggest potential hepatoprotective effects. However, translating these findings into clinical practice requires further rigorous investigation, including well-designed clinical trials. This review provides a foundation for future research efforts aimed at elucidating the full therapeutic potential of Argemone mexicana in liver health and cancer management.

Development of dark chocolate with inulin and sweetened with stevia extract obtained by pressurized hot water

Because of its taste, texture, and aroma, chocolate is consumed as a way to generate pleasant sensations. Due to its high caloric density, moderate consumption is recommended. Seeking to offer the benefits of this product to a more selective public, the aim of this research was to determine the chemical composition and sensory properties of a sugar-free dark chocolate added with inulin and sweetened with stevia extract obtained by pressurized hot water, which was compared with a commercial dark chocolate and accompanied by a sensory analysis of the samples. A completely randomized statistical experimental design was used to compare the properties of the alternative and commercial chocolates. The treatments were carried out in triplicate and the results obtained were analyzed by descriptive statistics and one-way analysis of variance with 95 % confidence level. The results showed that the treatment of stevia leaves with hot pressurized water allowed an extraction of 41.51 g of steviol glycosides for rebaudioside A and 6.76 g for stevioside per 100 g of leaves subjected to processing. The chemical analysis of the alternative and commercial chocolates indicated that the fat and total dietary fiber contents showed no significant difference (p > 0.05) between the dark chocolates, unlike the other components. Moisture, ash, fat, and protein contents were slightly higher in the two types of chocolate, and carbohydrate content was 4.1 % lower than in the commercial chocolate. Both products had 0 % added sugars and high dietary fiber content (> 37 %), and there was a reduction of 100 kcal/100 g compared to the commercial brand. Consumer sensory evaluation showed a higher level of liking (p < 0.05) for the elaborated chocolate with respect to the commercial product in attributes such as appearance, color, and texture. These findings suggest the use of stevia extracts obtained by pressurized hot water as a non-caloric sweetener for healthy, alternative dark chocolates suitable for people with diabetes.

Passion fruit peel-derived low-methoxyl pectin: De-esterification methods and application as a fat substitute in set yogurt

Passion fruit pectin, originally high methoxyl pectin, undergoes substantial conversion into low methoxyl pectin (LMP) through de-esterification. This de-esterification is significance for reducing the application of sugar in food, as calcium ions can replace excessive sugar during gel formation. In this study, LMPs derived from passion fruit pectin were prepared using four methods: low-temperature alkali, room temperature alkali, enzymatic, and dielectric barrier discharge plasma (DBD)-assisted enzyme (DBDE). The de-esterification conditions were optimized, leading to the selection of LMPs with a degree of esterification for the analysis of molecular weight, monosaccharide composition, and gel properties. The results revealed significant differences in the structure and properties of LMPs depending on the de-esterification method applied. The galacturonic acid content of LMPs significantly increased, with LMP from DBDE (LMP-DBDE) exhibiting the highest increase at 47.81 %. Additionally, the molecular weights of LMPs significantly decreased, with LMP-DBDE showing the smallest decrease. LMP-DBDE demonstrated higher apparent viscosity, thermal stability, and gel properties, facilitating the formation of gels. After 21 days of storage, 0.40 % LMP-DBDE yogurt showed no whey separation, significantly extending its shelf life. Therefore, LMP-DBDE exhibits potential as a fat substitute, combining the advantages of LMP with enhanced water-holding capacity, and presenting promising applications in low-fat dairy products.

Effect of benzoyl chloride treatment on morphological, thermal, mechanical, and hydrothermal aging properties of date palm/polyvinyl chloride (PVC) composites

The use of natural fibers has seen a significant rise in the composites sector, resulting in the creation of polymer composites with exceptional strength. These environmentally-friendly alternatives offer a compelling substitute for synthetic composites. This study explores the use of date palm waste as reinforcement for the fabrication of polyvinyl chloride (PVC) composites. A surface modification method was essential for improving the binding interaction between palm fibers and PVC composites. The two-hour benzoyl chloride treatment at 140 °C played a crucial role. The study examined the effects of hydrothermal aging on mechanical properties of composites, using various techniques such as surface morphology analysis, Fourier Transform Infrared spectroscopy, and Thermogravimetric Analysis, on composites made of untreated fibers and those treated with benzoyl chloride. Although the treatment of palm fiber-reinforced composites with benzoyl chloride improved their mechanical properties, it is crucial to note that hydrothermal aging reduced their tensile strength by 10%. Despite this, these composites prove to be well-suited for applications requiring moderate strength and stiffness in mild environmental conditions. These composites, while utilizing benzoyl chloride for surface treatment, still represent a more sustainable alternative to traditional synthetic composites by incorporating renewable date palm waste and enhancing mechanical properties, which potentially reduces overall environmental impact.

Microwave reflective properties of amorphous nanogranular composites (CoTaNb)x(MgO)1-x

The most important task of flexible and stretchable electronics is to modify the structure in nanoheterogeneous metal-dielectric media to control the properties of materials and create new small-sized devices based on them. In this paper, we present the results of experimental studies of the structure and microwave reflective properties in the frequency range of 8–12 GHz of amorphous nanogranulated composites (CoTaNb)x(MgO)1−x, 21.73 ≤ x ≤ 73.27 at.% with a thickness of 311–1040 nm. Niobium and tantalum, which are part of the metal alloy, are the most promising metals used in aircraft and rocket engineering, as well as in radio electronics and microprocessor technology, for example, as capacitors. The AFM method revealed a granular structure with a granule size from 70 to 200 nm at a metal alloy content of up to 51.70 at.%. The spectra of the microwave reflectivity as a function of frequency, the dependence of the reflectivity on the metallic phase content and the effective thickness of the composite layer are obtained. It is shown that a significant increase in the microwave reflectivity and its saturation are determined to a greater extent by the metallic phase content than by the effective layer thickness. The results of the experimental effect of magnetic fields with induction up to 0.3 T on the microwave reflectivity of composite films are presented. It is shown that magnetic fields can most effectively change the reflective properties of composites (from 8 % to 29 %) at the extremes of the microwave reflectivity of films with the lowest metallic phase content of 22.61–21.73 at.%. With an increase in the metallic phase content, the maximum change in the microwave reflectivity decreases exponentially.

Experimental, simulation, and theoretical investigations of gamma and neutron shielding characteristics for reinforced with boron carbide and titanium oxide composites

This study investigates the radiation shielding properties of composites containing polyester resin, boron carbide and titanium oxide in varying proportions. The radiation transmittance of the produced composites was measured using radioactive sources 241Am, 137Cs, 133Ba, 60Co, and 22Na across a photon energy range of 59.5 keV–1332.5 keV. To analyze radiation permeability, experimental geometry was simulated using Monte Carlo-based computer codes Monte Carlo N-Particle (MCNP), Particle and Heavy Ion Transport code System (PHITS) and FLUktuierende KAskade or Fluctuating Cascade (FLUKA), and the experimental data were compared with simulation results and theoretical data obtained from WINXCOM. The findings demonstrated a high degree of consistency between experimental, simulation, and theoretical results. Notably, the BCTiO50 sample, which included a 50% addition of TiO2, emerged as the most effective in photon radiation shielding. In addition to gamma shielding, the neutron shielding properties of the produced composites were evaluated using the FLUKA code, revealing that the BCTiO0 sample, with the highest percentage of boron, provided the best neutron shielding. This analysis included composites with decreasing boron carbide content by 10%, 20%, 30%, 40%, and 50% by weight, each replaced with titanium oxide, showcasing the potential applications of these polymer composites in radiation shielding.

Investigation on the loading rate dependence of electromechanical properties of graphene-cement composites under compressive loading

In this paper, the dependence of the electromechanical properties of graphene-cement composites on the loading rate is studied by combining experiment and theory. The graphene-cement composites are prepared using a wet dispersion technique combined with surfactant assist and ultrasonication treatment. Both monotonic and cyclic compressive experiments with different loading rates are conducted on the graphene-cement composites with different graphene contents to measure their mechanical, electrical and piezoresistive properties. The optimum dosage of graphene in cement matrix is about 0.05 wt%, which can increase the compressive strength by 35.7 % and 34.1 %, and decrease the electrical resistivity to 1.43 and 3.48 × 105 Ω•cm, respectively, after 14 and 28 d curing periods. The uniform dispersion of graphene with less layers endows the graphene-cement composites with very low percolation threshold of electrical conductivity (0.007 wt%), stable piezoresistive response, and good reproducibility. Furthermore, the mechanism of the loading rate on the strain sensing behavior is discussed, and a rate dependent theoretical model of resistance change is proposed to quantitatively predict the electromechanical responses. This study provides guidelines for the fabrication of highly strain-sensitive graphene-cement composites and the rate-dependent evaluation of their electromechanical properties in the fields of intelligent construction.

Learning based model for predicting mechanical properties and sustainable filler band for NBR composites using lignin and carbon black

Experimental determination of mechanical properties of rubber composites, such as tensile strength and hardness, involves complex multistage preparation procedures that are laborious and expensive. In this study, a hybrid filler of carbon black (CB) along with a sustainable filler of lignin is added for reinforcement in the nitrile butadiene rubber (NBR) matrix, with the total filler content varying from 10 parts per hundred rubber (phr) to 80 phr. This work aims to develop a data-driven predictive model for the mechanical properties of rubber composites. An artificial neural network (ANN) model using multilayer feed-forward back-propagation has been created to forecast the tensile strength (Ts) and hardness (Hd) of rubber composites. The model predicts the uniaxial tensile response and hardness using input parameters that include total filler and lignin loading levels. The effectiveness of the suggested prediction method was demonstrated by statistical analysis using confidence intervals, showing a prediction error between 5.47% and 3.23% for the Ts and between 3.03% and 1.85% for Hd at 95% confidence intervals. A sustainable green band could be defined in the developed model, which is handy for designers to replace CB with lignin in various NBR based products, such as hoses, seals, etc., without compromising on tensile strength and hardness.

Molecular sieves hybrid metal–organic framework for efficient simultaneously capturing carbon dioxide and collecting water from air

Water scarcity and climate change associated with global warming are two common challenges facing humankind. The simultaneous removal of water and carbon dioxide (CO2) from the air has become a popular candidate strategy to address these challenges. In this paper, molecular sieve@MOF composites were synthesized in-situ for the first time by adding ZSM-5 and HZSM-5 during the preparation of Mg/DOBDC. A comprehensive review of the air capture CO2 and water harvesting properties of the novel composites was also presented. Primarily, the effects of molecular sieve category and ratio on the composite were systematically investigated. Subsequently, the crystal structure, morphological composition and textural properties of the composites were characterized. Finally, CO2/H2O co-adsorption performance, adsorption and desorption cycle stability and adsorption mechanism were investigated. The results demonstrated that the metal nodes of Mg/DOBDC interacted with the molecular sieve surface functional groups to increase the metal active sites and porosity. The obtained 0.5HZSM-5@Mg/DOBDC MOF showed the maximum CO2 uptake of 15.90 mmol/g (0.1 MPa, 25 °C), which was 3.66 times the amount of Mg/DOBDC.

Progressive hollow engineering induced raspberry-like magnetoelectric microspheres via synergistic etching-assembly strategy toward boosted microwave attenuation

Optimizing the electromagnetic (EM) properties of composites through elaborate tailoring of their microstructures has become an attractive research branch, but determining the correlations between morphology, composition, and performance remains challenging. Herein, a novel progressive hollow engineering strategy is proposed for the construction of hollow CuFePBA (CF) precursors with asymptotic variations of cavities and Prussian blue analog (PBA) units based on a synergistic etching-assembly approach, subsequently combined with a polydopamine (PDA) coating and carbothermal process to acquire raspberry-like hollow Cu/Fe/Fe3C@NC (CFC) composites. The proposed approach addresses the drawbacks caused by organic ligand depletion or corrosive agent usage. We then present a systematic investigation of the mechanism by which the progressive hollow engineering-induced concurrent evolution of hollow cavities, phases, defects, and inhomogeneous interfaces contributes to the improvement of the dielectric properties of the CFC samples. An optimal reflection loss (RLmin) of − 60.42 dB at 3.29 mm was realized for the CFC-2 sample and the CFC-3 sample achieved an effective absorption bandwidth (EAB) of 4.4 GHz at an ultra-thin thickness of 1.29 mm. This work reveals the synergistic effects of compositional, interfacial, and defect variations on the EM wave attenuation properties of the composites, and will provide new design inspiration for novel absorbers with modulatable hollow architectures.

Effect of Filler Content and Treatment on Mechanical Properties of Polyamide Composites Reinforced with Short Carbon Fibres Grafted with Nano-SiO₂

Effect of Filler Content and Treatment on Mechanical Properties of Polyamide Composites Reinforced with Short Carbon Fibres Grafted with Nano-SiO₂

Effect of Ti2AlC on the microstructure and properties of Cu-graphite composites

Effect of Ti2AlC on the microstructure and properties of Cu-graphite composites

Structural, thermal, and radiation shielding properties of B2O3-TeO2-Bi2O3-CdO-Tm2O3 glasses: The role of Tm2O3

This study presents a detailed investigation into the structural, thermal, and radiation shielding properties of a new glass composition, labeled as (50-x)B2O3 + 30TeO2 + 10Bi2O3 + 10CdO + x Tm2O3 (where x = 0, 1, 2, 3, 4, 5 mol %). Various radiation shielding parameters such as mass attenuation coefficient, linear attenuation coefficient, half-value layer, mean free path, effective atomic number, and absorbed equivalent dose rates for neutrons were determined through experimental measurements. The study also employed theoretical calculations to assess the exposure buildup factor and effective removal cross-section for neutrons. Additionally, the SRIM program was utilized to investigate mass stopping power and projected range for proton and alpha particles. The structural characteristics of the glasses were analyzed using XRD and FT-IR, while thermal properties were examined through Differential Thermal Analysis (DTA). FTIR analysis revealed distinctive bands corresponding to Bi—O, B—O—B, and Te—O bonds. Glass transition temperatures (Tg) increased with Tm2O3 content, ranging from 422 °C to 444 °C. The radiation shielding properties of bismuth boro-tellurite glasses showed that a dose of 1.2025 μSv/h emitted from a fast neutron source was absorbed by 35.1574 % in pure glass and 40.0391 % in glass doped with 5 mol% Tm2O3. Incorporating Tm2O3 into the glass matrix significantly improved the shielding and thermal properties, thus enhancing their potential for advanced high-energy radiation absorption. This investigation contributes to a deeper understanding of how Tm2O3 enhances the structural and thermal attributes of these glasses, positioning them as promising materials for radiation shielding applications.

Dispersion of ZnO or TiO2 nanoparticles onto P. australis stem-derived biochar for highly efficient photocatalytic removal of doxycycline antibiotic under visible light irradiation

Abstract Biochar (BC) derived from reed stems was prepared by high-temperature pyrolysis, and two types of ZnO/biochar (ZBC) and TiO2/biochar (TBC) composite materials were synthesized via a simple hydrolysis method. These composites, compared to pure ZnO and TiO2, exhibit not only improved but significantly enhanced crystalline structures and larger specific surface areas. This enhancement in the physical and chemical properties of ZBC and TBC composites is a crucial aspect of our research, as it leads to a distinct red-shifted absorption edge and excellent visible-light absorption characteristics. The photocatalytic degradation efficiency of ZBC and TBC composite materials, a key finding of our study, was evaluated using doxycycline antibiotic as a simulated pollutant under visible-light irradiation. The results demonstrate a 6.0-fold and 7.3-fold increase in photocatalytic degradation efficiency of ZBC and TBC composites compared to pure ZnO and TiO2, respectively, further underscoring the significance of these enhanced properties. Furthermore, active species trapping experiments reveal that ·OH radicals are the dominant reactive species in the photocatalytic degradation process of doxycycline. A Langmuir–Hinshelwood kinetic model accurately represents this degradation process. Kinetic data indicate that the degradation rate constants (k) of ZBC and TBC catalysts are 4.314 × 10−2 min−1 and 3.416 × 10−2 min−1, respectively. The photocatalysts exhibit no significant decrease in degradation efficiency for ZBC and TBC even after the fourth cycle, indicating their relatively high reusability. These results suggest that ZBC and TBC materials can be used as stable, efficient, cost-effective, and sustainable photocatalytic composite materials for antibiotic-contaminated wastewater treatment.

The effect of using surface functionalized granite powder waste on fresh properties of 3D-printed cementitious composites

The production of low-emission additive manufactured cementitious composites using functionalized rock powders offers promising mechanical properties and significantly reduces cement consumption. The effect of powder functionalization on the rheological properties of the mixture remains unclear, so this study investigated how mechanical and chemical functionalization of granite powder waste affects the viscoelastic properties of a cementitious mixture for additive manufacturing. Compression tests were used to track stress-strain changes over time, while Vane and slug tests measured yield stress in mixes with 20 % and 40 % cement replaced by natural (NGP), sieved (SGP), and carbonated granite powder (CGP). The results showed that all three powders (NGP, SGP, and CGP) increased yield stress compared to the reference mix, with CGP having the smallest effect. The functionalization of granite powder may enable the creation of desirable viscoelastic mixtures using sustainable materials. We observed that functionalizing granite powder (SGP and CGP) accelerated changes in the mixture rheological properties, with yield stress increasing by up to 33 %, while NGP showed minimal impact, similar to the reference mix. Differences between the Vane and Slug test results were also identified and their limitations described.

Investigation of the Multiparameter Mix Proportion Design and Mechanical Properties of Polyvinyl Alcohol-Engineered Cementitious Composites

Investigation of the Multiparameter Mix Proportion Design and Mechanical Properties of Polyvinyl Alcohol-Engineered Cementitious Composites