Search

This research work aims to study the drilling behaviour of hybrid composite structures made of glass fibre-reinforced polymer matrix metallised with a surface aluminium layer produced via cold spray technology. The metal deposition creating the coating was optimised by applying a thermoplastic layer to the thermoset composite structure using the co-curing technique. Aiming to highlight the influence of the metallic coating on the workpiece's response during drilling, this research systematically analyses the effects of drilling parameters such as feed rate and spindle speed on delamination, burr formation and hole quality. In-process monitoring techniques, including thermocouple temperature and thrust force measurements, as well as energy consumption estimation, were utilised to evaluate drilling performance. The main findings demonstrate that selecting the composite side as the inlet surface results in the highest measured force and reduced delamination, meaning that aluminium coatings significantly impact drilling dynamics. [ABSTRACT FROM AUTHOR]

With the development of science and technology, the application of electronic products is extensive, and it is developing in the direction of miniaturization, integration, and high performance. However, the development of electronic products is limited due to capacitors low energy storage density. This study selects inorganic nanoparticles with high dielectric constant as fillers and polyvinylidene fluoride as the matrix of composite materials. It adopts a layer-by-layer casting method to prepare multilayer Ba 0.6 Sr 0.4 TiO 3 /PVDF composites. It is found that the dielectric and energy storage performances of the multilayer composites doped with Ba 0.6 Sr 0.4 TiO 3 are improved compared with the pure PVDF polymer films after the electrical properties test. A multi-layer composite material with a gradient distribution of fillers was designed and prepared to improve the energy storage density. The energy storage density of multilayer composites with a favorable gradient structure can reach up to 9.3 J/cm3 at 300 kV/mm. By analyzing the improved storage density mechanism, the results show that the design of the multilayer gradient structure can significantly reduce the electric field's local concentration, inhibit the formation of conductive paths, and significantly improve the composites' energy storage density. [ABSTRACT FROM AUTHOR]

Elastomeric foams are composite materials comprising of a polymeric elastomer and interconnected gas‐filled pores, endowing them with exceptional compliance and the ability to undergo large, reversible deformations along with substantial volume change. These foams find extensive utility in contexts demanding compliance and compressibility, such as impact protection and cushioning, spanning a diverse range of applications. Changing temperature can dramatically alter foam stiffness, strength and deformation characteristics specifically around the material's glassy‐rubbery transition temperature (Tg). With the aim of informing new constitutive model developments for elastomeric foams, we conducted a comprehensive series of large deformation, homogeneous compression and tension tests across strain rates from 10−2 s−1 to 100 s−1 and ambient temperatures ranging from −10°C to 50°C covering an even range around the material's Tg of 20°C. To achieve precise control of ambient temperatures during mechanical testing, we constructed a custom‐designed environmental chamber for controlling the ambient temperature from −10°C to 50°C with a variation of less than 1°C. The obtained digital image correlation based stress‐strain data shows significant tension‐compression asymmetry as well as significant dependence on strain rate and ambient temperature, especially above and below the glass transition temperature. We provide full access to these data sets for the future development of rate‐ and temperature‐dependent constitutive models. [ABSTRACT FROM AUTHOR]

This paper reports an experimental and numerical study on the mixed-mode I+II fracture characterisation of unidirectional AS4/low-melt-Polyaryletherketone (AS4/LMPAEKTM) composites. To address the fracture law characterising the material mixed-mode fracture behaviour, a suitable approach is used, simply applying two different loading conditions regarding five mechanical tests and specimen configurations. Scoping to characterise fracture under pure mode I loading and under mixed-mode I+II loading with mode I predominance, the peel test loading condition is used, respectively, for symmetric and asymmetric double-cantilever beam tests (DCB and ADCB). The three-point bending loading condition is used in order to characterise fracture under pure mode II loading by end-notch flexure test (ENF) and mixed-mode I+II with moderate and predominant mode II, respecting symmetric and asymmetric single-leg bending tests (SLB and ASLB). To diminish the influence of crack monitoring ambiguity on the crack length analysis during experiments, data reduction schemes based on the compliance-based beam method (CBBM) were used. Additionally, numerical finite element analyses were conducted in order to validate the data reduction method and the mode partition strategy based on cohesive zone modelling (CZM). Overall, a good agreement between numerical and experimental results was obtained, providing an adequate identification of the energy fracture criterion. [ABSTRACT FROM AUTHOR]

Bipolar plates play a crucial role in the performance and viability of proton exchange membrane fuel cells. Polymeric composites have demonstrated their potential as alternatives to graphite and metallic materials for bipolar plates due to their good corrosion resistance, lightweight nature, flexibility, and cost-effectiveness. However, these polymeric materials often suffer from low electrical conductivity. The incorporation of various electrically conducting fillers can improve the electrical conductivity of these materials. This work presents a comprehensive review of the utilization of polymeric materials-based composites for bipolar plates for proton exchange membrane fuel cells. Various aspects related to bipolar plates in proton exchange membrane fuel cells, including materials, fabrication techniques, applications, cost analysis, and the current status of proton exchange membrane fuel cells are discussed in this work. Both thermoplastic and thermoset-based composites are explored as matrix materials for bipolar plates, along with different conducting filler/reinforcement options, and their best results are also explored. The impact of traditional as well as emerging fabrication techniques on the performance of bipolar plates is evaluated, emphasizing the need to reduce the cost of bipolar plates for the commercialization of proton exchange membrane fuel cells. Furthermore, the paper also examines the applications and current status of proton exchange membrane fuel cells in India as well as worldwide. [ABSTRACT FROM AUTHOR]

Polymeric composite materials are in great demand in biomedical and water treatment applications. This is because they possess distinct characteristics and can fulfill specific biomedical needs, in addition to their ability to degrade dyes. This study successfully synthesized sustainable strontium titanate (STO) particles with an average size of 120 nm using the solid-state method. When these STO particles were mixed into a PCL-based polyurethane matrix, the matrix became hydrophilic with a contact angle of 58.60° and its mechanical strength enhanced by 320%. The morphology and surface roughness of the films were determined using FESEM and AFM techniques. The antibacterial studies of polymeric composites film against E. coli, Klebsiella pneumonia, and S. aureus , showing good zone growth, and showing enhanced swelling properties of 270% for wound healing and biomedical applications. The photocatalytic performance of the STO by degrading Methyl Orange (MO) and Congo Red (CR) under UV light, achieving degradation efficiencies of 92.25% for MO and 62.5% for CR over 150 min. These findings suggest that PU scaffolds and STO are suitable for biological and water treatment in industrial applications. [Display omitted] [ABSTRACT FROM AUTHOR]

The widespread availability of banana peels makes them an excellent resource for bio-fillers in developing environmentally conscious and biodegradable composites, serving as substitutes for plastic and synthetic waste. This study focuses on using banana peel waste as a bio-filler to produce lighter and cheaper materials. The extracted banana peels were subjected to alkali treatment to improve interfacial interaction, and their crystalline performance, functional categories, and morphological studies were examined using XRD, FTIR, and SEM techniques. Composite samples were fabricated with varying bio-filler ratios (0.0, 2.5, 5.0, 7.5, and 10%) to examine their thermo-mechanical and tribological attributes. The inclusion of banana peel in the epoxy matrix at up to 5% significantly enhanced mechanical performance, while 7.5% composites demonstrated higher thermal endurance with a degradation temperature of 395 °C and reduced water retention. Frictional wear of the specimens was assessed by varying sliding speeds under different loads, with the highest coefficient of friction and temperature observed under a 30 N force for BPC-10.0 specimens. This research innovatively uses banana peel powder (approx. 65 µm) to create polymeric composites, addressing the need for sustainable materials with higher specific modulus and strength compared to conventional substances. The study uniquely evaluates the physical, mechanical, structural, and tribological efficiency of raw and processed banana peel particles, with chemical modifications improving crystallinity and interfacial bonding. This comprehensive approach provides vital insights for developing sustainable alternatives to reduce plastic usage. [ABSTRACT FROM AUTHOR]

Water contamination is one of the biggest environmental issues the world is currently experiencing, and it is a result of growing industry and urbanization. The main causes of contaminated water are the textile industry and the colours included in waste effluent. The production of polymeric ferrite composites is the focus of this investigation. To the best of our knowledge these combinations of polymer and ferrites have not been synthesized before. The purpose of using these polymeric ferrite composites was to eliminate the artificially reactive Orange-122 dye from aqueous solutions. Various factors were optimized to get the best clearance, including pH (2–12), composite dose (0.01–0.3 g), contact time (10–120 min), temperature, and beginning dye concentration (20–200 mg/L). The acidic range (2–5) was shown to have the maximum dye removal of reactive dye, and the ideal composite dose was found to be 0.03 g/50 mL. Within the first sixty to ninety minutes, balance was reached. At 120–150 mg L–1, the maximum level of reactive dye clearance was attained. As the temperature was raised, the chosen dye was more effectively removed, indicating that the process was endothermic. Various models, including thermodynamic, kinetic, and equilibrium models, were used to verify. [ABSTRACT FROM AUTHOR]

In-situ consolidation of thermoplastic composites using Automated Fibre Placement (AFP) technology is an emerging manufacturing technique, offering tailored composite properties through customised processing parameters. Multiple competing parameters during AFP manufacturing influence the quality and mechanical performance of the laminates. These lay-up parameters are interrelated, and often require comprehensive experimental characterisation which is costly and time-intensive. This study aims to optimise the fracture toughness of in-situ consolidated thermoplastic composite (AS4/APC-2) and investigate the mechanisms that contribute to it. Taguchi's method is employed to efficiently analyse the effect of various process parameters at multiple levels. Based on the obtained results, a considerable effect of process parameters on Mode I and II fracture toughness is observed. The statistical analysis reveals that the Hot Gas Torch (HGT) temperature required for AFP processing significantly affects the Mode I fracture toughness, contributing to 33.8%. Whereas, the consolidation force, another key processing parameter in AFP notably affects Mode II fracture toughness, with the contribution of 81.8%. The analysis of variance (ANOVA) reveals interdependent processing parameter relations for both fracture modes. A validation test showed good agreement between the predicted fracture toughness and the experimental test. [ABSTRACT FROM AUTHOR]

Among several composite repair methods, single-sided bonded patch repair is a simple and time-effective method, but its post-repair tensile strength is usually low compared to that of double-sided repair and scarf repair. Despite the tensile loading, out-of-plane bending deformation is inevitable owing to the step-like load path and generates peel stress in the adhesive layer. This study proposes a variable stiffness (VS) patch that mitigates steep stiffness changes at the edge of the patch using a curvilinear fiber orientation and verifies its effectiveness in delaying patch debonding. The damage progress in the single-sided repaired quasi-isotropic CFRP laminate under tensile loading was predicted using three-dimensional finite element analysis with cohesive elements. Although patches debonded from one end in the loading direction, the VS patch with low stiffness near the end obtained a smaller out-of-plane deformation and a higher debonding onset strain than those of the standard quasi-isotropic patch. Furthermore, tensile tests of patch-repaired CFRP specimens demonstrated an increase in the debonding onset strain by the VS patch with a small variation. These results confirmed the effectiveness of the VS patch in the single-sided bonded repair of composite structures. [ABSTRACT FROM AUTHOR]

Development of new antibacterial materials for solving biomedical problems is an extremely important and very urgent task. This review aims to summarize recent articles (from the last five and mostly the last three years) on the nanoparticle/polymer composites for biomedical applications. Articles on polymeric nanoparticles (NPs) and hydrogel-based systems were not reviewed, since we focused our attention mostly on the composites of polymeric matrix with at least one inorganic filler in the form of NPs. The fields of application of newly developed antibacterial NPs/polymer composites are described, along with their composition and synthetic approaches that allow researchers to succeed in preparing effective composite materials for medical and healthcare purposes. [ABSTRACT FROM AUTHOR]

Polyurethane incorporated with nanofillers such as carbon nanotubes, basalt fibers, and clay nanoparticles has presented remarkable potential for improving the performance of the polymeric composites. In this study, the halloysite nanofiller-reinforced polyurethane elastomer composites were prepared via the semi-prepolymer method. The impact of different halloysites (halloysite nanotubes and halloysite nanoplates) in polyurethane composites was investigated. Scanning electron microscopy, X-ray diffraction, infrared spectroscopy, electronic universal tensile testing, and acoustic impedance tube testing were employed to characterize the morphology, composition, phase separation, mechanical properties, and sound insulation of the samples. The composite fabricated with 0.5 wt% of halloysite nanotubes introduced during quasi-prepolymer preparation exhibited the highest tensile strength (22.92 ± 0.84 MPa) and elongation at break (576.67 ± 17.99%) among all the prepared samples. Also, the incorporation of 2 wt% halloysite nanotubes into the polyurethane matrix resulted in the most significant overall improvements, particularly in terms of tensile strength (~44%), elongation at break (~40%), and sound insulation (~25%) within the low-frequency range of 50 to 1600 Hz. The attainment of these impressive mechanical and acoustic characteristics could be attributed to the unique lumen structure of the halloysite nanotubes, good dispersion of the halloysites in the polyurethane, and the interfacial bonding between the matrix and halloysite fillers. [ABSTRACT FROM AUTHOR]

This work presents the experimental results of a quasi-static penetration test of laminates on a polyurea-polyurethane matrix, reinforced with aramid, carbon and flax fibers. A total of 15 series of samples with different reinforcement configurations were prepared. A quasi-static penetration test was performed for coefficient SPR = 5. The SPR = Ds/Dp was calculated as the ratio of the support hole diameter (Ds) to the punch diameter (Dp). A punch with a rounded 9-mm diameter tip was used to penetrate the material. Percentage changes of penetration energy (%E) and maximum load (%P) compared to a non-hybrid laminate were calculated in order to estimate the impact of hybridization on the properties of laminates. The energy absorbed during the quasi-static penetration test was used to calculate the PSS (punch shear strength) of the laminates. Damage analysis was performed after the puncture test. It was observed that both the type of reinforcement and the configuration of the reinforcement layers have a potential impact on the obtained results and the laminate damage mechanism. [ABSTRACT FROM AUTHOR]

The physical microtopography, in an effective and stable manner, can powerfully confer biomaterials with enhanced osteoconduction for the repair of critical‐sized bone defects. However, the realization of the osteoconductive microtopography within a 3D porous scaffold is still unmet. Herein, this work presents a stone‐cottage‐inspired printing strategy to build microsphere patterned scaffolds with a tunable microtopography for accelerated bone regeneration. The customized composite inks of poly (lactic‐co‐glycolic acid) microspheres as “Stone” and alginate hydrogels as “Mortar” endow the fibers of as‐printed scaffolds with a stable and tunable groove‐ridge microstructure. Owing to this microtopography, microsphere patterned scaffolds significantly promote cell recruitment, immune response, angiogenesis, and osteogenesis. Meanwhile, compared to 55 and 85 µm, 25 µm width of groove‐ridge microstructure displays the most osteoconduction for repair of critical bone defects. Mechanistically, while cells prefer to adhere to microstructure with a bigger width and higher modulus in the early phase, this microstructure should also act as a barrier for cell growth and its smaller width is more beneficial for cell communication and differentiation in the later phase. Overall, it provides a robust strategy to fabricate the osteoconductive microtopography within a 3D scaffold, broadening the manipulation of physical morphology in tissue engineering. [ABSTRACT FROM AUTHOR]

The current study aims to introduce a new polymeric composite consisting of epoxy resin as the matrix and gadolinium oxide (Gd2O3) as the neutron adsorption ingredient. The shielding performance of the composite was assessed by neutron attenuation experiments with an Am-Be source and polyethylene moderator. The results of these experiments showed an appreciable agreement with the Monte Carlo simulations. Other characteristics of the composite, including mechanical strength, thermal stability, microtexture, and its chemical compositions, were examined using standard tensile test, thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, static light scattering analyses, and Fourier-transform infrared spectroscopy (FTIR). The results indicated that the new composites offer appreciable neutron absorption properties so that samples with 0.5%, 2%, 5%, and 10% Gd2O3 content could reduce the neutron beam intensity by 54%, 63%, 66%, and 70% at a thickness of 4 cm. [ABSTRACT FROM AUTHOR]

AbstractThis study focuses on assessing damage in polymer matrix composite sandwiches, crucial for structural integrity in aerospace, automotive and others industries. These composites, known for their high strength-to-weight ratio, are prone to delamination, debonding, and cracking. Early detection and precise evaluation of such damage can allow timely repairs and prevent catastrophic failures. The research integrates piezoelectric transducers, specifically piezo-copolymers (CP) and piezo-ceramics (PZT), into the structure for real-time health monitoring. Using four-point bending tests, damage is assessed through electrical capacitance, acoustic emission, and ultrasonic testing. The innovation lies in combining different transducers with multi-method diagnostics for enhanced accuracy and performance. [ABSTRACT FROM AUTHOR]

This study introduces a novel application of composite materials as Lost Circulation Materials (LCM), leveraging their high specific strength, non-abrasiveness, and environmentally friendly profile. A new formulation of Carbon Fiber Reinforced Polymer (CFRP) composites was developed using an advanced twin-screw extrusion process followed by compression molding. Their efficacy in sealing fractures was quantitatively assessed in accordance with American Petroleum Institute (API) standards using a Bridging Material Tester (BMT). Comparative analysis with previous studies on Bagasse Fiber Reinforced Polymer (BFRP) composites was conducted. Interfacial interactions and fracture morphology were examined through Scanning Electron Microscopy (SEM), revealing the CFRP composites' superior resistance to water absorption. The moisture absorption tests indicated that the CFRP absorbed 0.7% moisture after 24 h, compared to 15% for BFRP, suggesting enhanced durability in wet conditions. However, despite their robust mechanical properties, they exhibited lower fracture-sealing efficiency compared to BFRP composites. These findings not only underscore the potential of composite-based LCMs in enhancing drilling safety but also guide future research toward optimizing composite formulations for more effective field applications. [ABSTRACT FROM AUTHOR]

Far infrared radiation (FIR) within the wavelength range of 4–14 μm can offer human health benefits, such as improving blood flow. Therefore, additives that emit far infrared radiation have the potential to be incorporated into polymer/fabric matrices to develop textiles that could promote health. In this study, biochar derived from candlenuts and pyrolyzed with activated carbon (AC) was incorporated into polypropylene (PP) films and investigated for its potential as a health-promoting textile additive. The properties of biochar were compared with other far infrared (FIR) emitting additives such as hematite, Indian red ochre, and graphene. The addition of biochar increased FIR emissivity to 0.90, which is 9% higher than that of pristine PP. Additionally, biochar enhanced UV and near-infrared (NIR) blocking capabilities, achieving an ultra-protection factor (UPF) of 91.41 and NIR shielding of 95.85%. Incorporating 2 wt% biochar resulted in a 3.3-fold higher temperature increase compared to pristine PP after 30 s of exposure to an FIR source, demonstrating improved heat retention. Furthermore, the ability to achieve the lowest thermal effusivity among other additives supports the potential use of biochar-incorporated fabric as a warming material in cold climates. The tensile properties of PP films with biochar were superior to those with other additives, potentially contributing to a longer product lifespan. Additionally, samples with red ochre exhibited the highest FIR emissivity, while samples with hematite showed the highest capacity for UV shielding. [ABSTRACT FROM AUTHOR]

Liquid crystalline elastomers (LCEs) are a class of shape‐changing polymers with exceptional mechanical properties and potential as artificial muscles/polymer actuators. In this study, multifunctional LCE actuators with strain sensing and joule heating responsivity are developed. LCEs are successfully synthesized using the thiol‐ene two‐staged michael addition polymerization (TMAP) method. The LCE films are further functionalized via sequential polydopamine (PDA) and silver electroless coating. It is found that the PDA coating enabled the anchoring of the Ag particles to the LCE, thereby enabling the electrical conductivity of the Ag‐LCEs (<0.1 Ω cm−1). The studies confirm that the Ag/PDA coated LCEs can sense up to ≈30% strain, sense their own actuation strokes, and actuate at a rate of 1.83% s−1 while lifting a weight ≈50 times its mass in response to a 12 V 2A DC current. [ABSTRACT FROM AUTHOR]

The positron annihilation lifetime (PAL) spectroscopy characteristics of ethylene-propylene-diene monomer rubber (EPDM) composites reinforced with treated wheat husk fibers (WHFs) were investigated for the first time. PAL spectroscopy is employed to study the free volume of polymers. The use of lignocellulosic materials as reinforcement in polymeric composites has gained attention due to their low cost, availability, and eco-friendliness. In this study, the impact of the loading concentration on the interfacial adhesion between the EPDM matrix and WHFs is quantified, along with the evaluation of swelling measurement and tensile properties. Additionally, the nanoscopic properties derived from PAL spectroscopy correlate with the composites' macroscopic properties. In addition, the dielectric properties of the investigated samples have been studied, and their conductivity has been calculated. To determine the conduction mechanism within these samples and how it is affected by the addition of WHF, the change in electrical conductivity with the frequency of the external electric field applied to the samples was studied, and from this, the conduction mechanism was determined, and the barrier height value was calculated. The experimental results provide insights into the relationship between the structure and properties of EPDM-WHF biocomposites, offering valuable knowledge for developing sustainable and high-performance materials. [ABSTRACT FROM AUTHOR]

The completed study investigated the creation of Martian regolith simulant composite parts using injection molding and additive manufacturing. Traditional manufacturing techniques such as injection molding are not feasible on the Martian surface therefore in-situ processes must be developed using additive manufacturing processes to prepare habitats prior to having a human presence on the surface. The goal of this study was to investigate the impacts of additive manufacturing on the material property values between parts made using traditional injection molding and additive manufacturing. Martian regolith simulant composite pellets were created by combining a Martian regolith simulant at 40 wt% loading with polypropylene via twin screw extrusion. This material was then used to create test specimens using injection molding and additive manufacturing. Samples underwent tensile, flexural, Izod impact, and immersion density tests according to ASTM International and standardized test instructions. Additive manufactured parts saw a nearly 40% reduction in tensile and flexural strength with more than double the tensile modulus when compared to injection molded parts. The flexural modulus for additive manufacturing was around 36% that of the injection molded part with a minor decrease in density of around 13%. The collected test results suggested that while there were differences in the material property values between the manufacturing processes, a more interesting foaming behavior of the extrudite was observed during the additive manufacturing process resulting in an extremely rough and pitted surface. This rough surface finish was a stark comparison to the smooth injection molded parts. This observed foaming behavior in the polymeric composite material during thermal processing prompted the theory that thermal releases from the Martian regolith simulant was the most likely cause of the observed differences. Pellet surface moisture tests, Martian regolith simulant thermogravimetric analyses, and literature reviews of thermal decomposition of the Martian regolith simulant constituents revealed that most likely olivine releases oxygen and hydrated silica releases water during the thermal processing of the Martian regolith simulant composite. During a closed mold process such as injection molding, these volatile gases are forced out of the part by the pressures of the molding process, but in an open to atmosphere process such as additive manufacturing these gases foam to the surface during cooling leaving the part with an inferior surface finish. [ABSTRACT FROM AUTHOR]

The increasing demand for chip heat dissipation has led to more challenges in designing and regulating thermal interface materials with high performance. It is crucial to have a comprehensive understanding of the design and mechanism of thermal conduction path built by thermal conductive fillers. Diamond, in particular, has garnered significant attention. In this study, we constructed three-dimensional particle random distribution models of diamond/silicone rubber composites based on the morphological characteristics of common industrial-grade diamond. We also conducted experiments with different morphologies and filling amounts of diamonds in silicone rubber to better understand the effect of diamond fillers on the thermal conductivity of the composites. From the model simulation, thermal conductivity and actual LED temperature rise tests, the study reveals that broken single-crystal diamond with lamellae or rod-like with large aspect ratio or radius-thickness ratio is easier to form thermal transfer paths than spherical or spherical-like diamond under low filling content. Ultimately, the silicone rubber composites filled with intact hexa-octahedral single-crystal diamonds achieve the highest thermal conductivity as a result of the formation of more comprehensive three-dimensional heat dissipation network (1.357 W/(m K), 80 wt.%). In comparison with silicone rubber composites filled with spherical Al2O3 (0.995 W/(m K), 80wt.%) and pure silicone rubber (0.21 W/(m K), 80 wt.%), the thermal conductivity increases by 36% and 546%, respectively. The revelation of the construction law and mechanism of different diamond morphologies on the thermal conduction path of thermal interface materials provides a theoretical basis for broadening the application of diamond in the design of thermal interface materials. [ABSTRACT FROM AUTHOR]

The combination of a microcavity and a microsphere has been proposed in this work to manipulate light in terms of emission wavelength and propagation direction. A microcavity with a layer of molecular photoswitch between two one-dimensional photonic crystals of polyvinyl carbazole and cellulose acetate has been designed. To tune the microcavity, the molecular photoswitch has been excited taking into account its cyclization upon irradiation at 313 nm and its cycloreversion at 450 nm. In this way, the emission peak of the microcavity switches from 508.5 nm to 525 nm. A polystyrene microsphere with a radius of 1 μ m is placed near the microcavity. With the detector at an angle of 8°, the emission at 525 nm is 1.73 times higher with respect to the emission at 508.5 nm, while at 10.8°, the emission at 508.5 nm is 1.45 times higher with respect to the emission at 525 nm. The value of these findings is that they offer the experimentalists a ready means to compare the optical data of these types of composites with theory. [ABSTRACT FROM AUTHOR]

Erythrosine B/PVA polymeric composite films were prepared with different concentrations of Erythrosine B (EB) as 0, 1, 2, and 4 wt% of EB utilizing the casting procedure. The crystal structure of Erythrosine B /PVA films was identified by X-ray diffraction patterns (XRD). The frequency (100 Hz − 1 MHz) reliance on both dielectric constant (ε1) and dielectric loss (ε2) was investigated. Both ε1 and ε2 of Erythrosine B/PVA polymeric composite films decreased with increasing frequency and increased by rising percent EB wt%. The ac conductivity of Erythrosine B/PVA films showed increased behavior by raising frequency. Moreover, the frequency exponent (s) decreased slightly from 0.99 to 0.96 with increasing concentrations. The increase in Erythrosine B content enhances the values of for EB/PVA polymeric composite films. The density of states N(Ef) is calculated at specific frequencies for different concentrations of EB for Erythrosine B /PVA polymeric composite films, and it has values in the order of 1018 cm− 3 eV− 1. [ABSTRACT FROM AUTHOR]

A novel polymeric composite was created using polyethylene polymers as the primary component, supplemented with varying weight proportions of micro-sized basalt rock powder. Basalt was incorporated into the base material at concentrations ranging from 20 to 40% by weight. The homogenous distributions of the basalt powder within the epoxy layers were affirmed using the scanning electron microscope (SEM) as well as the FTIR spectra for the fabricated composites were analyzed. The gamma-ray shielding properties for the fabricated composites were examined using the narrow beam transmission method on NaI (Tl) detector. The linear attenuation coefficient measurement shows an enhancement in the linear attenuation coefficient from 0.134 to 0.156 cm−1 by raising the basalt powder ratio from 0 to 40 wt%. These results were associated with an enhancement in the radiation shielding properties of the fabricated composites from 12.6 to 14.2% and the lead equivalent thickness reduced from 9.3to 8 cm by raising the basalt powder concentration from 0 to 40 wt%, respectively. Based on the findings, incorporating micro-sized basalt powder into the epoxy resin improves the gamma-ray shielding capabilities of the produced composites in comparison to various polymers documented in prior studies, especially E-B40. In terms of radiation protection, it can be inferred that E-B40 shows promising potential as a shielding material for gamma rays with low energy, offering increased protection with reduced thickness. [ABSTRACT FROM AUTHOR]

Polymeric composites are prone to undergoing damage, such as microcracks, during their operation, which can ultimately lead to catastrophic failure. To contradict such a problem, efforts have been carried out, by the scientific community, towards developing self-healing composites that, by mimicking biological systems, can autonomously and prematurely repair flaws, extending the durability and improving the security of materials. The present review explores the progress made in this area, focusing on extrinsic self-healing methods, as these can be employed to a variety of materials. Reservoir-based techniques, which resort to capsules, hollow fibers or microvascular networks, and thermoplastic-based ones are overviewed, prioritizing innovative approaches made in recent years. At last, promising practical applications for self-healing composites are highlighted and future challenges and opportunities are pointed out. [ABSTRACT FROM AUTHOR]

This study aims to combine, using a numerical tool, different phenomena of hygromechanical coupling in a unidirectional carbon/epoxy composite and to compare the results obtained with the cases where these couplings are considered separately. The first case of coupling considers the effect produced by the mechanical state on the diffusive behavior of the material. This was accomplished using the free volume theory, which links the trace of the matrix strain tensor to the moisture absorption capacity and the diffusion coefficient. The second case takes into account plasticization, that is, the effect of humidity on the mechanical properties of composites, without modifying the diffusion parameters. Finally, these two mechanisms are combined in a third configuration, which represents the original contribution of this present work. The results include the water content profiles, the diffusion coefficient, the transverse Young's modulus, the transverse hygroscopic expansion coefficient, as well as the induced local mechanical states. The interest of the work carried out is to pave the way for the extension to more complex materials, such as plant fiber biocomposites, in which the water absorption by the hydrophilic fibers should not be neglected anymore. [ABSTRACT FROM AUTHOR]

[Display omitted] • SEM micrographs describe the morphology of homogeneous mixtures in composites. • A high surface roughness of 130 nm supremacy a high-water contact angle of 104°, indicating strong hydrophobicity. • Excellent microwave attenuation of −18 dB reflection loss signifies efficient wave dissipation. • A high absorption rate (99.99%) and damping factor around 0.95 demonstrate superior microwave absorption. • Increased storage modulus suggests enhanced stiffness and elasticity. As technology advances, the demand for effective microwave-absorbing materials (MAM) to mitigate electromagnetic wave interference is growing. Two-dimensional (2D) materials are increasingly favored across various fields for their high specific surface area, electrical conductivity, low density, and dielectric loss properties. This study presents lightweight nanocomposites composed of graphene nanoplatelets blended with epoxy resin (ER) and cardanol with silane-functionalized (SFC) as a toughening agent. The resulting nanocomposites exhibit a high surface roughness of 130 nm and an enhanced hydrophobicity, as evidenced by a high contact angle. Notably, the ER/SFC/GNP sample at 3 wt% (0.075 g) achieves a minimum reflection loss value of −18 dB at a thickness of 10 mm, indicating improved impedance matching and enhanced dielectric loss capability. The increasing damping factor ratio to approximately 0.95 further augments the reflection loss performance. The research aims to develop cost-effective, efficient, lightweight graphene-based nanocomposite absorbers. [ABSTRACT FROM AUTHOR]

In the last decades, corrosion control of metals and their alloys has been of environmental, aesthetic, economic, and technical importance. Ecologically acceptable, environment-friendly, and readily available corrosion inhibitors are one of the best options for protecting metals against corrosion. In this regard, use of polymers for inhibiting metallic corrosion is an authentic and acceptable practice, with a low environmental threat. Polymers may be used as composites, blends, or isolation for optimal inhibitory effects. Inhibition efficiencies of corrosion inhibitors were determined using mass loss, electrochemical impedance spectroscopy, potentiodynamic polarization techniques, etc. The present study gives the idea about natural, synthetic, and conducting polymers and their utilization for corrosion inhibition applications. Effects of halide ions as additives or surfactants on their anticorrosion performances are also discussed. Polymeric materials as coatings are reviewed to align with recent research interests, such as cost-effectiveness, environment friendliness, and self-healing products, which are more convenient to synthesize and use in future applications.

The study aimed to advance composite technology by exploring the potential of recycled materials, specifically high-density polyethylene (HDPE) composites reinforced with sugarcane bagasse fibers. This research not only addresses environmental concerns by utilizing recyclable materials but also aims to offer significant technical, economic, and social advantages. The investigation focused on formulating and evaluating these composites, considering varying proportions of untreated sugarcane bagasse fibers and examining the effects of chemical treatment with stearic acid at different temperatures. Using a conical twin-screw extruder and injector, the researchers produced and analyzed the composites both morphologically and mechanically. The principal findings indicated that the inclusion of untreated fibers improved the stiffness and tensile strength of the composites. Nevertheless, adhesion between the fibers and the matrix was compromised, especially with higher fiber concentrations. Chemical treatment at 40 °C significantly improved fiber/matrix interactions, thereby enhancing the reliability and mechanical properties of the composites. This treatment led to substantial increases in tensile and compressive strengths, particularly noticeable in composites containing 10%–15% fiber by weight. These results not only demonstrate the feasibility of using recycled HDPE and sugarcane bagasse fibers in composite materials but also suggest avenues for further exploration. Future research could delve deeper into optimizing chemical treatment processes to achieve even better adhesion and mechanical performance. Moreover, exploring broader applications in industries such as automotive, aerospace, naval, civil engineering, and packaging could unlock new opportunities for these sustainable composites. This study thus paves the way for advancing composite technology towards more environmentally friendly and economically viable solutions.

To address the residual stress induced during the cure of fibre reinforced thermoset polymer composites, two different approaches were suggested for coupling a non-dominated sorting genetic algorithm (NSGA-II) with finite element (FE) simulations based on a viscoelastic constitutive law. These two approaches were proposed with consideration of different ways of integrating NSGA-II and the FE model. In Approach A, NSGA-II was performed based on results from a series of simulations under various combinations of cure variables. Alternatively, Approach B employed NSGA-II to iteratively update and optimise the cure profile for subsequent simulations. Results indicated that both approaches achieved simultaneous reductions in cure time and macroscale residual stress, with Approach B showing further improvements due to the direct coupling between the NSGA-II and simulations. Specifically, the maximum residual stress and cure time optimised by Approach A were reduced by 5%–9% and 22%–50% respectively, while those obtained by Approach B were reduced by 7%–10% and 32%–49% respectively, compared to those based on the manufacturer recommended cure profile. The evolution of stress in composites based on optimised cure profiles from these two approaches was also elucidated. Additionally, microscale modelling further revealed a 3%–5% reduction in the average residual stress within a representative volume element (RVE) model was also shown, depending upon the approach adopted. Ultimately, by combining a NSGA-II and FE simulations, the optimisation of cure time and residual stress at the macroscale and cure time together with a reduction of microscale stress could be realised. [ABSTRACT FROM AUTHOR]

Additive manufacturing of composites offers advantages over metals since composites are lightweight, fatigue and corrosion-resistant, and show high strength and stiffness. This work investigates the tensile and flexural performance of continuous carbon-fiber reinforced (CCF) composites with different guide angles and number of layers. The cost and printing time analyses were also conducted. Tensile specimens with a contour-only specimen and one CCF layer with a 0° guide angle exhibited nearly comparable strength values. Increasing the number of CCF layers enhances the tensile properties. For the identical cost and reinforcement amount, 0°/0° provides a higher tensile strength and elastic modulus compared with 15°/−15°. The same phenomenon was observed for 15°/0°/−15° and 0°/0°/0°. The samples with one and two reinforcement layers had similar stiffness and maximum load values for flexural tests. For the samples with four layers, there was a considerable improvement in stiffness but a minor decrease in the maximum load. [ABSTRACT FROM AUTHOR]

Polymeric composites for manipulating the sustained release of an encapsulated active ingredient are highly sought after for many practical applications; particularly, water-insoluble polymers and core–shell structures are frequently explored to manipulate the release behaviors of drug molecules over an extended time period. In this study, electrospun core–shell nanostructures were utilized to develop a brand-new strategy to tailor the spatial distributions of both an insoluble polymer (ethylcellulose, EC) and soluble polymer (polyvinylpyrrolidone, PVP) within the nanofibers, thereby manipulating the extended-release behaviors of the loaded active ingredient, ferulic acid (FA). Scanning electron microscopy and transmission electron microscopy assessments revealed that all the prepared nanofibers had a linear morphology without beads or spindles, and those from the coaxial processes had an obvious core–shell structure. X-ray diffraction and attenuated total reflectance Fourier transform infrared spectroscopic tests confirmed that FA had fine compatibility with EC and PVP, and presented in all the nanofibers in an amorphous state. In vitro dissolution tests indicated that the radical distributions of EC (decreasing from shell to core) and PVP (increasing from shell to core) were able to play their important role in manipulating the release behaviors of FA elaborately. On one hand, the core–shell nanofibers F3 had the advantages of homogeneous composite nanofibers F1 with a higher content of EC prepared from the shell solutions to inhibit the initial burst release and provide a longer time period of sustained release. On the other hand, F3 had the advantages of nanofibers F2 with a higher content of PVP prepared from the core solutions to inhibit the negative tailing-off release. The key element was the water permeation rates, controlled by the ratios of soluble and insoluble polymers. The new strategy based on core–shell structure paves a way for developing a wide variety of polymeric composites with heterogeneous distributions for realizing the desired functional performances. [ABSTRACT FROM AUTHOR]

Composite materials play a crucial role in various industries, with plastic composites being particularly significant. This research specifically focuses on producing cotton fabric layers to reinforce polymeric composites. The experiment is designed in two phases. In the first stage, woven fabric is produced using roving as weft insertion instead of the conventional threads or spun yarns. This modification enhances the absorbency of the resin matrix during composite production, leading to improved properties. The second stage of the experiment involves manufacturing composite materials using different fabric structures (plain, twill, and sateen) and varying numbers of fabric layers (1, 3, and 5). This is achieved through a novel process called Vacuum Assisted Resin Transfer Molding (VARTM), which is used for fabric composites instead of the traditional laminated composites. VARTM offers advantages in terms of production efficiency and composite quality. To evaluate the physical and mechanical properties of the resulting composites, several tests are conducted. These include tensile properties testing, bending rigidity testing, measurement of composite thickness, and determination of density. The test results provide valuable insights into the performance of fabric composites under different conditions. Furthermore, the experimental results are compared with simulations conducted using the Finite Element Method (FEM) through COMSOL software. The agreement between the experimental and simulated results confirms the reliability of the proposed approach. [ABSTRACT FROM AUTHOR]

Localized foaming of polymers is promising to fabricate polymeric composite structures for applications in biomedical, aerospace, automotive, etc. However, the severe pyrolysis and carbonization of polymer chains during localized foaming may degrade the bulk strength. Herein, a mild localized foaming strategy is proposed to fabricate poly(lactic acid) (PLA) micro‐foams within dense PLA matrices using ultrafast lasers. The PLA substrates doped with graphene (Gr) and azodicarbonamide (AC) are developed for mild foaming. A picosecond laser is applied to pattern PLA micro‐foams on the PLA/Gr/AC substrates to fabricate porous/nonporous micro‐composite structures. The thermal behavior of the PLA/Gr/AC substrates is characterized to evaluate their capability in photothermal conversion and mild foaming during ultrafast laser pulses. To optimize the laser foaming process, the microstructure of the laser‐foamed PLA processed with different laser parameters is studied. It demonstrates that the oxidation of the functional groups dominates the side reactions on the PLA chains with slight variation in molecular weight during laser foaming, indicating that the PLA chains keep almost intact and mild localized foaming is realized. Furthermore, the developed technology is demonstrated for micro‐patterning and texturing, material toughness programming, and shape memory programming, showing promising applications for smart materials, metamaterials, micro‐robotics, and biological scaffolds. [ABSTRACT FROM AUTHOR]

Two‐photon Polymerization (2PP) process for high‐resolution 3D printing presents an opportunity to design micro‐scale structures with a high surface‐to‐volume ratio for highly responsive devices. However, these acrylate or thiol‐based resins are electrically insulating and non‐functional in nature, therefore limiting their widespread application in biosensing and biotechnology. Here, a novel conductive polymeric composite resin to print conductive 3D micro‐structures via the 2PP technique is developed and its application in sensing are demonstrated. The composite consists of acrylate‐based 2PP resin and Poly(3,4‐ethylenedioxythiophene)‐poly(styrenesulfonate) (PEDOT:PSS), a conductive and biocompatible organic semiconductor The PEDOT:PSS incorporation in resin through Raman and X‐ray photoelectron spectroscopy (XPS) is studied. An electrical conductivity of 3.5 × 102 S cm−1 in a 20 µm long and 10 µm high 3D printed micro‐structure which is suitable for electronic applications is achieved. An ultra‐fast micro‐3D printed humidity sensor with a response and recovery time of 0.15 and 0.3 s respectively is demonstrated. The printed sensors show high sensitivity in humidity levels of 0–80%RH. As a proof of concept, the real‐time respiration of a human body is recorded, implying a potential application in health monitoring systems. [ABSTRACT FROM AUTHOR]

Mechanical and thermodynamical properties and thus machinability of carbon fibre reinforced polymer composites significantly depend on the fibre orientation relative to the load direction. However, the orientations of the fibre groups in polymer composites reinforced by chopped carbon fibres are stochastic; therefore, the properties and machinability of such composites are challenging to plan, predict and optimise. We developed four different and novel approaches for fibre detection in polymer composites reinforced by chopped carbon fibres: (i) detecting the fibres through naked eye supported manual drawing, (ii) digital image processing of optical images, (iii) machine learning-based fibre detection, and (iv) rectangle fitting on the outputs of the automated processes using the Chaudhuri and Samal method. The applicability of the novel approaches was tested through optically captured images of polymer composites reinforced by chopped carbon fibres. The developed methods are each capable of detecting fibre groups at the top and bottom of the composite plate with certain limitations. The rectangle fitting approaches performed the best from the point of view of correctly identifying of fibre groups, followed by the machine learning-based and the conventional digital image processed, respectively. As a result of this study, the machining process planning and condition monitoring of polymer composites reinforced by chopped carbon fibres is more deeply supported. [ABSTRACT FROM AUTHOR]

This paper presents a numerical study of the influence of geometry and orientation of fibres on the mechanical behaviour of a hemp fibre reinforced polypropylene, obtained with injection. Tensile tests and multiplexing mode Dynamic Mechanical Analysis (DMA) were carried out in order to determine the mechanical behaviour of the neat and reinforced material. A numerical homogenization was then performed with the elastic hemp fibres for aligned and random orientation as well as a reconstructed microstructure obtained with injection simulation to correlate with tensile tests. The simulations were performed for sphero-cylinder and curved fibres and the results were compared to FFT results obtained directly on micro-tomography images as well as experimental data. The results showed that the complex geometry of the fibres can be approximated with a random 3D orientation of sphero-cylinder shaped fibres, a reasonable hypothesis leading to a simplification of the problem and an easier process of design of parts made with such materials. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to fabricate the acrylic-based polymeric composite coating with a hydrophobic surface associated with natural oil polyol (NOP) and polydimethylsiloxane with the incorporation of 3 Wt.% SiO2 nanoparticle (SiO2np) against the corrosive NaCl media. Design/methodology/approach: The structural properties of the formulated polymeric composite coatings were investigated by using Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, water contact angle (WCA) and cross-hatch (X-Hatch) tests. The WCA measurement was used to study the surface wettability of the formulated polymeric composite coatings. The corrosion protection performance of the nanocomposite coated on the mild steel substrate was studied by immersing the samples in 3.5 Wt.% NaCl solution for 30 days using electrochemical impedance spectroscopy. Findings: The enhanced polymeric composite coating system performed with an excellent increase in the WCA up to 111.1° which is good hydrophobic nature and very high coating resistance in the range of 1010 Ω attributed to the superiority of SiO2np. Originality/value: The incorporation of SiO2np into the polymeric coating could enhance the surface roughness and hydrophobic properties that could increase corrosion protection. This approach is a novel attempt of using NOP along with the addition of SiO2np. [ABSTRACT FROM AUTHOR]

In this investigation, composites consisting of polypyrrole (PPy), polyaniline (PAN), and sodium alginate combined with rice husk (RH) biomass were fabricated, utilizing them as adsorbents for naphthalene. The optimization of key process variables, including pH, pesticide concentration, composite dosage, contact time, and temperature were systematically undertaken to enhance the removal efficiency of naphthalene. Notably, the composites exhibited promising efficacy in adsorbing naphthalene, with native rice husk and PPy/RH (at pH 4), PAN/RH (at pH 5), and Na-alginate/RH (at pH 6) displaying the highest removal rates. Optimized conditions for composite dosage, temperature, and contact time were determined as 0.05 g, 30 °C, and 90 min, respectively, ensuring efficient removal of naphthalene. The adsorption capacities for naphthalene were found to be 22.04, 23.15, 23.89 and 21.67 (mg/g) for RH, PAN/RH, PPY/RH and Na-alginate/RH, respectively. The Langmuir isotherm and pseudo-first-order kinetics models aptly described the adsorption process onto the composite material. The surface morphology and functional groups involved in the biocomposite formation were examined through scanning electron microscope (SEM) and Fourier-transform infrared (FTIR) techniques. These analyses confirmed that PPy, PAN, and Na-alginate composites with RH biomass exhibit high effectiveness in naphthalene removal, showcasing their potential application in the remediation of naphthalene from effluents. [ABSTRACT FROM AUTHOR]

In this research, composite materials were prepared by combining polypyrrole (PPY) and polyaniline (PAN) with Oryza sativa (OS). These biocomposites were utilized for the adsorption of Nitenpyram (insecticide), from aqueous solutions. The study involved the optimization of various process variables including contact time, pH, adsorbent dose and initial Nitenpyram concentration. The maximum sorption efficiency of OS for Nitenpyram was observed at pH 2, biosorbent dose of 0.05 g, an initial Nitenpyram concentration of 125 mg/L and contact time of 30 min. To analyze the Nitenpyram adsorption process, the adsorption data for OS and its composites (OS-PPY and OS-PAN) were subjected to equilibrium isotherms and kinetics models (pseudo-first and pseudo-second-orders). The Langmuir isotherm and pseudo-second-order explained the Nitenpyram adsorption data. Furthermore, the feasibility of the adsorption was evaluated by employing thermodynamic studies. The outcomes of the study demonstrated the promising efficiency of the synthesized biocomposites for Nitenpyram removal, which was 37.03, 43.0 and 35.71 (mg/g) in the case of OS, OS-PPY and OS-PAN composites. These findings suggest that the composites have promising potential for the removal of pesticides from wastewater, contributing to the development of effective strategies for environmental remediation. [ABSTRACT FROM AUTHOR]

Conducting polymer hydrogels (CPHs) are composite polymeric materials with unique properties that combine the electrical capabilities of conducting polymers (CPs) with the excellent mechanical properties and biocompatibility of traditional hydrogels. This review aims to highlight how the unique properties CPHs have from combining their two constituent materials are utilized within the biomedical field. First, the synthesis approaches and applications of non-CPH conductive hydrogels are discussed briefly, contrasting CPH-based systems. The synthesis routes of hydrogels, CPs, and CPHs are then discussed. This review also provides a comprehensive overview of the recent advancements and applications of CPHs in the biomedical field, encompassing their applications as biosensors, drug delivery scaffolds (DDSs), and tissue engineering platforms. Regarding their applications within tissue engineering, a comprehensive discussion of the usage of CPHs for skeletal muscle prosthetics and regeneration, cardiac regeneration, epithelial regeneration and wound healing, bone and cartilage regeneration, and neural prosthetics and regeneration is provided. Finally, critical challenges and future perspectives are also addressed, emphasizing the need for continued research; however, this fascinating class of materials holds promise within the vastly evolving field of biomedicine. [ABSTRACT FROM AUTHOR]

Extrusion-based three-dimensional (3D) printing of gelatin (Gel) is crucial for fabricating bone tissue engineering scaffolds via additive manufacturing. However, the thermal instability of Gel remains a persistent challenge, as it tends to collapse at mild temperatures. Current approaches often involve simply mixing Gel particles with various materials, resulting in biomaterial inks that lack uniformity and have inconsistent degradation characteristics. In this study, acetic acid was used to dissolve Gel and polycaprolactone (PCL) separately, producing homogeneous Gel/PCL dispersions with optimal pre-treatment performance. These dispersions were then combined and hybridized with nano-hydroxyapatite (n-HA) to create a composite printing ink. By evaluating the printability of the ink, the optimal conditions were identified: a n-HA concentration of 50% (w/w), a printing temperature of 10–15 ℃, a printing pressure of 2.5 bar, and a printing speed of 7 mm/s. The resulting biomaterial inks, with a composition of 25% Gel, 25% PCL, and 50% n-HA, demonstrated excellent printability and stability, along with significantly enhanced mechanical properties. As a result, 3D scaffolds with high printability and shape fidelity can be printed at room temperature, followed by deep freezing at -80 ℃ and cross-linking with vanillin. The Gel-based composite scaffolds demonstrated excellent biocompatibility, cell adhesion, cell viability and nano-hydroxyapatite absorption in vitro. Additionally, in vivo experiments revealed that the bioactive scaffold biodegraded during implantation and significantly promoted bone regeneration at the defect site. This provides a promising strategy for treating bone defects in clinical setting. In conclusion, the Gel/PCL/n-HA biomaterial inks presented here offer an innovative solution for extrusion bioprinting in the field of bone tissue engineering. [ABSTRACT FROM AUTHOR]

AbstractThe tensile properties and damage behaviors of prepreg-resin transfer molding (RTM) co-cured composite bolted T-joints, consisting of an internal skeleton and an external skin, were investigated through experimental and numerical methods. With the validated finite element model, the effects of adding load-carrying beams, the corner radius and the stacking sequence were investigated. Results indicate that the novel T-joint, weighing only 55.7% of an equivalent sized 2A12 aluminum T-joint, can achieve 82% of the aluminum T-joint’s tensile stiffness and 107% of its proportional limit load. Damage in the joint initiates near the bolt holes and leads to delamination failure within the skeleton. With load-carrying beams including bolt holes, the tensile stiffness and ultimate load increase to 1.11 and 1.51 times that of the original configuration, respectively, with the final failure mode shifting to the fracture of the base panel. With the final failure mode unchanged, the ultimate load remains essentially unchanged with increasing the corner radius. Under tensile loads, the preferred stacking sequence for the skeleton is [0/+45/90/−45]nS. For the skin, the greater the number of ±45° plies, the higher the ultimate load, while the greater the number of 90° plies, the higher the tensile stiffness. [ABSTRACT FROM AUTHOR]

Thermal residual stress generated during curing is known to be detrimental to mechanical performance of a carbon composite. Fiber prestressing technique has been developed for decades to counterbalance these negative effects. Although there have been some achievements in development of the prestress mechanisms, these are mainly based on the extrapolations from macroscopic mechanical characterizations, lack of direct evaluation of the in‐situ in‐plane strain or stress evolution mechanisms, in order to reveal the impact induced by different prestressing methods. Here, we investigated the in‐situ strain evolution mechanisms in producing a prestressed carbon composite. Since clamping of the uncured prepreg is the most challenging, both the strain evolutions with and without precured prepreg edges were evaluated to reveal the underlying mechanisms induced by stress relaxation during fiber prestressing. Mechanical tests in terms of Charpy impact and three‐point bending, as well as fractured morphology were carried out to evaluate the prestress effects. The underlying mechanisms were then proposed to reveal the fundamentals in producing a prestressed composite. These are expected to revolutionize industrial production and applications of prestressed polymeric composites, indicating detrimental mechanisms on precuring strip ends following conventional prestress procedures. Highlights: There is an optimal prestrain level to maximize properties of a composite.Internal strain development is dependent on the fiber clamping methods.Stress relaxation is beneficial to induce compressive stress within a composite.In‐situ strain evolution mechanics is revealed for prestressed carbon composite. [ABSTRACT FROM AUTHOR]

Highlights Fabric‐reinforced shape memory polymeric composites (SMPC) have shown great potential in the design of intelligent deformation structures. In this work, the weft‐knitted fabric inserted with weft yarns was developed as reinforcement to fabricate the shape memory epoxy polymer (SMEP) composites. The effects of weft yarn, loop density and direction on the shape memory performance of SMPC under different bending radii were experimentally investigated. The results show that the SMPC have good shape fixity ratios and shape recovery ratios of around 98%. As compared with those of SMPCs without inserting weft yarns, the SMPCs with weft yarns have shorter shape recovery time, and the recovery force of SMPCs with weft yarns in the 0° and 90° directions shows an increase of 86.4% and 79.5%, respectively. The recovery force of SMPC improve 3.7 times compared to SMEP. The multiscale models of SMPC were established with basis of the results of micro‐computed tomography scanning of specimens and viscoelastic theory. The surface buckling behaviors of SMEP and SMPC specimens after U‐bending load were discussed. Finally, the deformation of loops and weft yarns of SMPC were analyzed to reveal the shape memory mechanism. Shape memory polymeric composites (SMPC) with weft yarns has shorter shape recovery time. Recovery force of SMPC with weft yarns was obvious enhanced. Multi‐scale viscoelastic models of SMPC were established. Surface buckling behaviors of SMPC after U‐bending load were revealed. [ABSTRACT FROM AUTHOR]

Adsorption has been reported to be optimal among oil spill cleanup methods due to its simplicity, low capital and operational cost, high removal efficiency and environmental friendliness. However, its continuous usage has been linked to generation of enormous waste, after oil spill cleanup, to which use of reusable oil sorbents has been proposed as a possible solution. Synthetic organic oil sorbents have high mechanical properties compared to other categories of oil sorbents, but they suffer low adsorptive capacities. To address this problem, among other nanoparticles, rGO have been infused in polymeric materials to produce composite oil sorbents characterized with high adsorptive capacities. In this research, surface modified rGO was infused in waste expanded polystyrene, to produce electrospun PS/FrGO composite sorbents by solution blending and electrospinning method. Adsorptive capacities of produced composites were evaluated in four oil samples. Functionalization of rGO was found to cause removal of residual oxygen containing functional groups such as hydroxyl (–OH), and resulted in more hydrophobic surface. Infusion of FrGO, in waste expanded polystyrene resulted into composites with increased surface area, from 71.50 m2/g for pure PS20 to 353.45 m2/g, 429.18 m2/g, 456.14 m2/g for PS20 infused with 1, 2 and 4wt% of FrGO. Increase in oil sorption capacities of the composite, observed in four oil samples corresponds to improved surface area. Produced composites show good recyclability in the four oil samples, at least up to the third sorption cycle. Highlights: Modification of Graphene oxide (GO) to reduced Graphene Oxide (rGO) rGO was functionalized and infused in Polystyrene (PS) to form PS/FrGO composite PS/FrGO composite was applied to oil–water mixture for oil adsorption Reusability of composites produced was evaluated. [ABSTRACT FROM AUTHOR]

In parallel with technological developments, the need for affordable, functional and sustainable materials is increasing day by day. At this point, wood composite materials, which provide many economic and environmental advantages compared to traditional polymer matrix composites, attract great interest due to their functionality in a variety of engineering applications. In this study, the structural properties of functional wood plastic composites were examined before the sustainability analysis and the current market analysis was made by evaluating the usage areas of these materials Furthermore, information about these materials' production methods is presented, and approaches for improving material properties are evaluated. The literature review compiled integrated information on the recent progress of these composites and the development of material properties. Thus, by emphasizing the importance of wood-plastic composite materials in terms of sustainability, it is aimed to provide researchers with a basis for the structural properties, production technologies and sectoral trends of these materials. [ABSTRACT FROM AUTHOR]