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For photosensitive polyurethane systems, reactive diluents are indispensable components whose main role is to reduce the viscosity of the polyurethane prepolymer to meet the requirements of the photocurable 3D printing technology for high fluidity of the precursor solution. Generally, the reactive diluent would be involved in the photocuring reaction, which in turn has a remarkable impact on the mechanical, reaction kinetics, and thermodynamic characteristics of the photosensitive polyurethane system. However, this feature is usually neglected in the study of photosensitive urethane acrylate (PUA) systems, so there is a considerable necessity to investigate the mechanism of active diluents in the photocured reaction of PUA systems. In this work, the effects of α-methyl groups along the chains of diluent molecules on the photoreaction kinetics, photocurable 3D printing, mechanical and mechanical properties, and thermodynamic characteristics of PUAs were investigated employing hydroxyethyl methacrylate and hydroxyethyl acrylate as active diluents, respectively. The relationship between chemical structure and kinetics of PUA systems was also elucidated by using dynamic mechanical analysis tests. The results demonstrated that the α-methyl group blocks the migration of reactive radicals, reduces the efficiency of the photoreaction, and causes an increase in the rigidity and strength of the molecular chain. This study not only revealed the effect of α-methyl on the kinetic mechanical and thermal performance of PUA systems but also paves the way for the development of a new class of photosensitive PUA materials used for the photocurable 3D printing technology. [ABSTRACT FROM AUTHOR]

Nanocellulose‐reinforced composites hold great promise for outperforming the original polymer matrix by offering exceptional properties, including outstanding barrier characteristics achieved through the establishment of convoluted pathways for the diffusion of water vapor and gases, as well as superior mechanical and thermal properties. Nevertheless, a significant challenge when employing nanocelluloses as reinforcements in polymers arises from their limited compatibility with the polymer matrix, primarily attributed to the abundance of surface hydroxyl groups.To address this limitation, this study focuses on the acetylation modification of cellulose nanocrystals (CNC) and nanofibers (CNF) to enhance their compatibility with the polymer matrix. Poly(butylene adipate‐co‐terephthalate) (PBAT) nanocomposites were developed by incorporating 1 wt% of both untreated and acetylated cellulose. The process involved the molten state mixing of these components using a twin‐screw mini extruder, conducted at 160°C for 7 min. The efficacy of the acetylation process was verified through Fourier transform infrared spectroscopy (FTIR). Scanning electron microscopy (SEM) analysis confirmed the favorable interaction and dispersion of nanocelluloses within the polymer matrix. Importantly, introducing these fillers did not compromise thermal stability but notably enhanced the hydrophobic characteristics of the samples, as confirmed by contact angle measurements. Dynamic mechanical analyses further demonstrated the compatibility and effective interaction between the polymer and fillers. This research uniquely provides a comparative analysis of the effects of acetylated CNC and CNF within a PBAT matrix, unveiling distinct interactions and performance enhancements. Each type of nanocellulose exhibits its own characteristic ways of bonding and dispersing, leading to varying performance improvements for the material. This comparison elucidates the nuanced roles that these nanocelluloses play in reinforcing composites, offering insights into optimizing their contribution to polymer matrices. By demonstrating the differential impact of CNC and CNF post‐acetylation, our study contributes significantly to the field of polymer science, guiding future applications of nanocellulose‐reinforced materials in advanced engineering and sustainability efforts. [ABSTRACT FROM AUTHOR]

The current market's imperative demand necessitates the research and development of advanced polymer composites, especially those incorporating nanofillers. Carbon nanotubes, in particular, have attracted significant attention within research and development for their potential in creating multifunctional composites. This study aims to evaluate the impact of incorporating carbon nanotube buckypapers (BP) on the thermal and electrical properties of poly (aryl ether ketone) (PAEK)/glass fiber (GF) composites. The BP was prepared through vacuum filtration and integrated into PAEK/GF composites with varying stacking sequences, followed by hot compression processing. The degradation behavior of the laminates was investigated using thermogravimetric analysis (TGA). The viscoelastic properties, evaluated by dynamic mechanical analysis (DMA), suggested an increase in stiffness with the inclusion of BP in two of the analyzed stacking sequences. Thermal conductivity, measured via the pulse laser method, showed results comparable to the base laminate (0.153 W/m·K). Meanwhile, electrical conductivity, assessed using the four‐point probe method in the in‐plane direction, revealed semiconductor properties, achieving a mean value of 3.162 S/cm for one of the samples, indicating electrical anisotropy within the multifunctional composite material. [ABSTRACT FROM AUTHOR]

Dynamic mechanical analysis (DMA) is a powerful technique for characterizing the mechanical properties of a wide range of materials. However, the importance of DMA in studying organic/polymer semiconductors has not been fully appreciated. In this Highlight, we explore recent advancements in the use of DMA in understanding the viscoelastic and mechanical properties and thermal transitions of organic semiconductor materials. In particular, the insights gained from DMA can serve as new guides for the device optimisation of organic solar cells towards stable operation. Furthermore, we present key findings, challenges, and future directions to advance the application of DMA in organic electronics. [ABSTRACT FROM AUTHOR]

Recent studies have hypothesized that the reinforcing effects of boehmite nanoparticles (BNPs) in polymer nanocomposites (PNCs) are partly related to the particles themselves and partly to the water released from the BNP during curing. In this work, PNCs made from dried BNP (dBNP) with concentrations up to 15 wt% are investigated to differentiate particle and water related effects. The observed trend of the storage modulus in dynamic mechanical thermal analysis measurements was found to be independent of the drying procedure. Stiffness maps from intermodulation atomic force microscopy showed that dBNP leads to a stiffening of the interphase surrounding the particles compared with the unaffected epoxy matrix, while a softer interphase was reported for PNCs with as received BNP. A slight decrease in the glass transition temperature was observed by broadband dielectric spectroscopy related to a lowered crosslink density due to the particles. A significantly higher decrease was reported for PNCs with BNP, attributed to water influencing the curing process. In conclusion, the stiffening of PNC with BNP is related to the particles themselves, while the release of water causes the formation of a soft interphase in the vicinity of the particles and a significant decrease in crosslink density. [ABSTRACT FROM AUTHOR]

AbstractFunctionally graded design transforms polymer composites without altering their properties. These composites change only the surface exposed to severe temperatures, leaving the rest unchanged. This study analyses ceramic additions’ effects on polymer thermal stability and crystallinity. Dynamic mechanical analysis (DMA) examined viscoelastic behaviour and thermogravimetric stability. Alumina, silicon carbide, and hafnium carbide ceramic powders increase thermal stability. DMA examined how ceramic additives affected composite viscoelasticity. The functionally graded design barely affects ceramic adhesive thermal properties. The ceramic adhesive remained stable at 800 °C with only 6% weight loss, while the other two disintegrated before 600 °C. [ABSTRACT FROM AUTHOR]

In this study, poly (ethylene-co-vinyl acetate)/mesoporous silica EVA/SBA-15 nanocomposites, containing 0.5, 1.5, and 2.5 wt% of unfunctionalized and functionalized SBA-15 were prepared by melt blending in an internal mixer. Mesoporous silica was synthesized through the sol-gel method and modified by hexadecyltrimethoxysilane (HDTMS). Several characterizations were performed; including Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), mechanical properties, dynamic mechanical analysis (DMA), and dielectric study to characterize the physicochemical properties of elaborated materials. The results revealed the successful synthesis and functionalization of mesoporous silica, as confirmed by the FTIR and SEM. The crystallinity of the nanocomposites decreased and the elastic modulus increased with the incorporation of the mesoporous silica. Measurement of tensile properties shows that the tensile strength of the nanocomposite content of 1.5 wt% F-SBA-15 is 17.2% is higher as compared to pure EVA. DMA analysis validates the improvement in mechanical properties of the EVA/SBA-15 samples. SEM images displayed well-dispersed F-SBA-15 nanoparticles and enhanced interfacial adhesion between the phases. TGA indicates the enhancement of the thermal stability of nanocomposites as compared with the pure EVA matrix. The surface functionalization presented an approach to preparing nanocomposites with enhanced thermal stability and a low dielectric constant. [ABSTRACT FROM AUTHOR]

In this work, a mesoporous silica (SBA-15) was synthesized using a hydrothermal method and the surface of the SBA-15 was further modified by utilizing the organosilane compound γ- aminopropyltriethoxysilane(APTES); FT-IR testing confirmed the successful grafting of these organic groups onto the surface of the SBA-15, the result being the AP-S. Composite films were subsequently prepared through a casting method, with SBA-15 and AP-S serving as the inorganic filler particles, and PVA acting as the matrix material. These films were characterized by tensile texts, dynamic mechanical analysis, scanning electron microscopy, and dielectric measurements. The results showed that the tensile modulus, loss modulus and dielectric properties of the modified AP-S/PVA composite films were improved compared with those of SBA-15/PVA, with the tensile strength being the largest at 145.25 MPa when the AP-S content was 2%. This result combined with the SEM analysis, shows that the incorporation of SBA-15 modified by APTES into PVA films can effectively improve the dispersion of SBA-15 in the PVA films, which can also explain the performance enhancement. [ABSTRACT FROM AUTHOR]

This research focuses on the mechanical characterization of FG material graded with Graphene nano-platelets (GPLs) in the transverse direction. Different weight percentages of GPL (0–2 wt. %) were incorporated into epoxy resin for manufacturing the FGM using a simple casting method and the effects were analyzed. This paper aims to enhance the material’s performance, especially focusing on its potential use in biomedical tools. Mechanical tests including assessment on tensile, flexural, impact strength, and microhardness demonstrated substantial improvement in strength and stiffness as compared to other nanocomposite structures. Microstructural analysis using scanning electron microscopy (SEM), Fourier-Transform Infrared Spectroscopy (FTIR), and X-ray Diffraction (XRD) analysis which hint at the strong chemical interaction and physical association of GPL nanofiller with the epoxy resin. Thermal analysis was conducted using the Dynamic Mechanical Analysis (DMA) test, which revealed enhanced thermal stability of the FG specimen with a higher glass transition temperature than other carbon nanofillers mixed in epoxy resin. This is advantageous for the FG material to maintain its glassy state, maintaining safety and reliability during high-temperature medical applications. All these findings indicate that the proposed FG-GPL material possesses the necessary mechanical properties, suggesting that customized nanofiller integration could lead to significant advancements in medical procedures, such as in vivo stomach biopsy treatments, drug delivery systems, etc. The material also meets specific anatomical requirements and reduces the risk of malfunction, thereby ensuring patient safety as justified by current experimental investigations. [ABSTRACT FROM AUTHOR]

Cross-linked poly(N-isopropylacrylamide), a typical representative of smart thermo-responsive polymers, usually shows a broad range of lower critical solution temperature (LCST) of 28–60 °C, which needs to be precisely fine-tuned in a narrow range to widen its applications. This work details the preparation of dual responsive (temperature and pH) flexible graft copolymeric hydrogel films through free radical polymerization of N-isopropylacrylamide (NIPAm) with acrylated epoxidized linseed oil (AELO) derived from linseed oil. The broad LCST of PNIPAm is fine-tuned more precisely to a narrow range of 30–33 °C with an optimized content of AELO. Further, temperature response is clearly demonstrated with the transmittance analysis of swelled gels above and below the LCST, which is also confirmed by dynamic mechanical analysis. Furthermore, different concentrations of curcumin were included in the responsive matrix to impart antioxidant properties and pH-dependent colour-changing abilities. The effect of AELO grafting and inclusion of curcumin on physicochemical properties of copolymeric hydrogel films, namely, swelling, morphology, and tensile strength, is investigated. In vitro cell studies showed that the resultant hydrogel films exhibited desirable biocompatibility with human keratinocyte and fibroblast cell lines. The results presented in this study demonstrate the potential of AELO-co-PNIPAm copolymeric hydrogel films as a viable functional material for medical patches, smart curtains, and other applications. [ABSTRACT FROM AUTHOR]

This study mainly focused on the hot-stretching-induced oriented crystallization structure of isotactic polypropylene (iPP) granules specialized for capacitance films (i. e. electrical grade iPP). A series of characterization tools, including differential scanning calorimetry, wide-angle X-ray diffraction, two-dimensional small-angle/wide-angle X-ray scattering, and dynamic mechanical analysis, were employed to determine the long-period spacing, orientation degree, crystallinity, melt point and chain relaxation behavior of iPP. The stretching deformation resulted in a highly oriented fibrillar morphology. A strain-induced crystallization enhancement was observed, in which both of the orientation degree and crystallinity increased continuously with an increasing in the strain. Two types of lamellae with thicker or thinner thicknesses were newly formed during the hot-stretching process. The thicker one can be attributed to the melt-recrystallization mode, while the thinner one is ascribed to the strain-induced crystallization mechanism. The dependence of strain on their crystallinity and melt point seemed to be weak. Moreover, the electric density difference between the amorphous and crystalline phases decreased with an increase in the strain, and meanwhile the chain relaxation temperatures related to different condensed states became close to each other. [ABSTRACT FROM AUTHOR]

Highlights This study assesses the effectiveness of a specially developed surface‐modified carbon black, both on its own and in combination with nano‐silica, as a hybrid filler for ethylene–propylene–diene monomer (EPDM) rubber compounds. The modification process, which included treatment with a silane coupling agent, resulted in enhanced curing characteristics. The ∆Torque values for compounds incorporating the modified carbon black exceeded those of other formulations by 25.85%. Scanning electron microscopy (SEM) analysis demonstrated improved filler dispersion and better compatibility between rubber and filler due to the surface modification. The silane‐modified carbon black showed considerable enhancements in mechanical properties, particularly in tear resistance, with increases in tensile and tear strength of 22.46% and 34.86%, respectively, following surface treatment. Dynamic mechanical analysis (DMA) indicated the influence of both surface modification and filler type, revealing that the combination of modified carbon black and nano‐silica achieved a reduction in rolling resistance of 20.41% and enhanced ice and wet grip performance by 7.95%. Additionally, modified carbon black displayed varying effects on the glass transition temperature. Thermal gravimetric analysis (TGA) confirmed that the thermal stability of the compounds was consistent, while solvent resistance improved with surface modification, as shown by swelling ratios. Thermodynamic analysis indicated that the surface modification of carbon black positively influences the elasticity and chain mobility of the rubber compounds studied. In conclusion, the careful selection and optimization of filler materials and their modifications are essential for customizing the properties of rubber compounds to satisfy specific performance criteria and applications. Promising EPDM compounds were prepared with Silane‐Modified CB and Nano‐Silica. Silane‐modified CB effectively improved the curing properties of the EPDM compound. The ΔTorque and cross‐link density of modified CB/EPDM show the highest value. Modified CB/Nano‐Silica/EPDM exhibited significant improvement in tear strength. Modified CB/Nano‐silica/EPDM have lower rolling resistance and higher wet grip. [ABSTRACT FROM AUTHOR]

As an important infrastructure, the floating platform plays a significant role in coastal and oceanic development. The single‐point mooring system anchored by piles has been widely used to support floating offshore platforms. However, few studies in the field of floating structures focused on the dynamic reliability and mechanical analysis of the mooring pile foundation under wind and wave vibration. A Monte Carlo‐based mooring pile reliability analysis method was introduced in this paper, which could consume the calculation source significantly. Based on the Monte Carlo simulation, the dynamic reliability of the mooring pile system of the floating platform was analyzed and discussed. Finally, considering the material cost, the design of the mooring pile of floating platform was optimized. The simulation work presented here also will contribute to a deeper understanding of civil engineering works' pile foundation. [ABSTRACT FROM AUTHOR]

With isophorone diisocyanate and polytetrahydrofuran as basic raw materials, dimethylolpropionic acid and 2,3‐dihydroxypropanesulfonic acid triethylamine salt (DHPSTEA) as chain extension agents, trimethylolpropane as crosslinking agent, N, N‐dimethylethanolamine as neutralizer, the high‐solid carboxylate/sulfonate waterborne polyurethane (SC‐HWPU) was synthesized. The effect of COO−/SO3− molar ratio on the properties of SC‐HWPU was studied. Fourier transform infrared and x‐ray photoelectron spectroscopy results demonstrated that the SC‐HWPU molecular chain contained carboxylate and sulfonate groups. The results of thermogravimetric analysis, dynamic mechanical analysis, and mechanical properties of SC‐HWPU film indicated that higher DHPSTEA content was favorable for the thermostability and mechanical properties when the total dosage of hydrophilic groups was invariable. When the mole ratio of COO−/SO3− is 8:2, the solid content of the prepared SC‐HWPU3 emulsion can reach to 51.6%, which has excellent storage stability and alkali resistance stability. Subsequently, the application of SC‐HWPU emulsion on the fixed‐island type polyamide/polyethylene terephthalate copolymer superfine fiber non‐woven fabric single‐coating process was analyzed, and the water‐base superfine fiber non‐woven fabric was prepared. Scanning electron microscopy showed that there was still a large amount of SC‐HWPU filled in the superfine fiber gap after alkali‐decrement, indicating that SC‐HWPU has excellent alkali resistance. [ABSTRACT FROM AUTHOR]

In this study, the operational conditions of a low‐cost in‐house‐built single screw filament extruder including operational parameters of extruder temperature (170–190°C) and screw speed (20–40 rpm) were evaluated in terms of the quality and dynamic‐mechanical properties of extruded PLA filaments. The designed experimental parameters were used to investigate the impact of operational parameters on filament diameter by Taguchi model where the predicted responses were evaluated. Results showed superior performance with R2 value of 0.9898. The measured filament diameters validated the predicted responses, and the error percentage was in the range of 0%–2.1%. Furthermore, in order to classify and distinguish filaments, we adept the artificial neural network (ANN) model classifier, and the measured dynamic mechanical analysis (DMA) values at certain temperatures were taken into consideration where the classes they belonged to be determined. Results reveal successful classification accuracy of filaments in the range of 94.82%–99.98% depends on different cases of classification process. [ABSTRACT FROM AUTHOR]

Wood is a versatile material extensively utilized across industries due to its low density, favorable mechanical properties, and environmental benefits. However, despite considerable research, the diversity in species with varying compositions and properties remains insufficiently explored, particularly for native woods. A deeper understanding of these differences is crucial for optimizing their industrial applications. This study investigated the composition, tensile strength, flexural strength, Young's modulus, bending stiffness and elongation at break, thermal behavior, and viscoelastic properties of three Brazilian native wood species: Araucaria angustifolia (ARA), Dipterix odorata (DOD), and Tabeuia ochracea (TOC). The density of these woods showed a linear correlation with mechanical properties such as Young's modulus (0.9) and flexural modulus (0.9). The research revealed a linear correlation between the woods' density and mechanical properties, with lignin content emerging as a key determinant of thermal stability. This study highlights the importance of understanding wood species' composition and physical properties, and provides valuable insights into their behavior. [ABSTRACT FROM AUTHOR]

Phthalate plasticizers are gradually restricted in PVC products due to the escalating demand for health and environmental safeguards. Here, novel poly(glycerol ester) plasticizers(PGE), were synthesized utilizing biomass-derived glycerol and 1,4-cyclohexanedicarboxylic acid as raw materials via an esterification condensation reaction, with n-octanoic acid serving as an end-capping agent, adjustment of reactant ratios yielded PGE-1 and PGE-0.75, subsequently evaluated for their efficacy in PVC applications. FT-IR and GPC analyses elucidated potential structures and molecular weight distributions of the plasticizers, revealing oligomeric PGE with molecular weights spanning 1000–2000 g mol−1. Mechanical properties, thermal stability, dynamic mechanical analysis, and migration resistance of PVC plasticized with PGE-1 and PGE-0.75 were compared against those employing conventional plasticizers, including di(2-ethylhexyl) phthalate (DEHP), dioctyl terephthalate (DOTP), and acetyl tributyl citrate (ATBC). The hyperbranched network structure and high molecular weight of PGE conferred superior thermal stability and migration resistance to the plasticized PVC samples. Notably, the T50% of PGE-1/PVC film surpassed that of films plasticized with DEHP, DOTP and ATBC by 107.92, 95.17 and 111.14 °C, respectively. The weight loss of PGE/PVC film in distilled water, anhydrous alcohol and petroleum ether was below 2 wt% during 48 h. Furthermore, the weight loss of each PVC film was below the safety value (5 wt%) during 10 d in three different food simulants. Overall, the obtained poly(glycerol ester) plasticizers exhibit promise as phthalate replacements, owing to their favourable attributes in human health and environmental protection. The poly(glycerol ester) plasticizers derived from biomass glycerol, 1,4-CHDA and n-octanoic acid exhibited superb thermal stability and migration resistance far more than commercial plasticizers in PVC, resulting from the hyperbranched network structure. [ABSTRACT FROM AUTHOR]

Highlights This study discussed the effects of different contents of Nickel‐titanium alloy particles (NiTip) on the vibration properties of carbon fiber reinforced polymers (CFRP) and further verified the test results by dynamic mechanical analysis tests while analyzing the effects of NiTip on the thermal stability of CFRP. The test results showed that 1.0 vol% of NiTip was the most effective in reducing the vibration transmission rate of the CFRP while improving its thermal stability. The modal of the CFRP composite cantilever beam is analyzed using the finite element method. In addition, the mechanical properties of CFRP with different NiTip contents were tested, including tensile, flexural, interlaminar shear and impact properties. The test results showed that 1.0 vol% of NiTip was most effective in improving the flexural properties, tensile properties and interlayer shear properties of CFRP. At the same time, 3.0 vol% of NiTip was most effective in improving the impact properties of CFRP. In addition, the fracture surfaces of CFRP reinforced with different NiTip contents were microanalysed to elucidate the enhancement mechanism. This study developed a multifunctional composite material with both vibration damping and high performance. These results provide essential guidelines for the optimal design and application of NiTip reinforced composites in vibration control, structural and aerospace applications. The effects of different Nickel‐titanium alloy particles (NiTip) levels on the vibration and mechanical properties of carbon fiber reinforced polymers (CFRP) were investigated. The influence of NiTip addition on the loss factor and thermal stability of CFRP was evaluated. SEM images were used to analyze the influence mechanism of uniform dispersion of NiTip on the reduction of vibration transmission rate of CFRP and the improvement of mechanical properties of CFRP. [ABSTRACT FROM AUTHOR]

Highlights The mechanical properties of carbon fiber (CF) reinforced thermoplastic polymer composites are primarily governed by the interphase between CFs and matrix. However, the inherent inertness of CF surfaces combined with the high viscosity and processing temperatures of thermoplastic resin often result in relatively weak interfacial bonding. This study aims to enhance the interfacial adhesion of carbon fiber reinforced polyamide 6 composites to improve their mechanical properties. CFs were de‐sized and oxidized, followed by re‐sizing with silanized carbon nanotubes. Fracture morphology and composition analysis of the fibers were conducted, and the fibers were subsequently incorporated into composites for mechanical testing. Results revealed a 20.0% increase in tensile strength, a 25.11% increase in flexural strength, and a 24.88% increase in interlaminar shear strength for the resized‐carbon fiber reinforced polyamide 6 composites compared to the pristine‐carbon fiber reinforced polyamide composites. The cross‐sectional morphology of the modified composites exhibited a zig‐zag fracture pattern. Dynamic mechanical analysis indicated that the modified fibers required higher activation energy for the free movement of the polyamide 6 molecular chain. These findings suggest that surface treatment enhances the interfacial adhesive between CF and resin, thereby significantly improving the mechanical properties of carbon fiber reinforced polyamide 6 composites. An efficient and reliable carbon fiber surface treatment method is proposed. Surface modification improves surface chemical activity of carbon fibers. Composites show substantial improvements in mechanical properties. Interfacial performance enhancement mechanism of composite was revealed. [ABSTRACT FROM AUTHOR]

Highlights Poly(butylene adipate‐co‐terephthalate) with or without thermoplastic starch is often used as a biodegradable matrix in composites reinforced with 5 and 10 wt% of either microfibrillated cellulose or cellulose nanocrystals. If dispersion of the fillers is well studied, their orientation in melt blended composites requires further understanding. In this study, the effect of a controlled shear rate on the orientation of the filler was investigated to understand how shear rate affects orientation and how orientation affects mechanical properties of the composites. To this end, composites prepared by melt mixing and then compressed were taken as a reference state of low orientation. On the contrary, to orient the fillers, extrusion through a slit die with a determined shear rate was carried out. Results of tensile tests, microscopic observations, atomic force microscopy and dynamic mechanical analysis in the melt showed that orientation of fillers in the flow axis was possible for shear rates higher than 13 s−1. The orientated samples presented enhanced mechanical properties in the elastic domain as opposed to unoriented samples. In general, orientation of fillers leads to uniaxial stiffness at lower filler content with much better ductility. However, this was observed only on samples for which the percolation of the filler was not obtained in the unoriented state, otherwise, orientation proved to be detrimental to the elastic mechanical properties because of the rupture in the formed network. Orientation can be controlled during processing. Sufficient shear rate is required. Orientation improves mechanical properties. Orientation might have a negative effect on rigidity in case of existing network. [ABSTRACT FROM AUTHOR]

AbstractThis study contributes valuable insights into optimizing ultraviolet-curable synthesized polyurethane-acrylate (PUA) coatings through tailored MgF2 nanocomposite formulations. The chemical structure of PUA was analyzed via Fourier transform infrared spectroscopy, confirming strong interactions between MgF2 nanoparticles and PUA segments. The interactions were further supported by thermogravimetric analysis and dynamic mechanical thermal analysis, highlighting enhanced thermal stability and viscoelastic properties in the nanocomposites compared to neat PUA coating. Thermogravimetry exhibited a notable increase in temperature of maximum degradation rate with higher MgF2 content, from 420.9 °C for neat PUA to 436.5 °C for PUA nanocomposites, indicating improved thermal stability with MgF2 integration. Analysis of viscoelastic behavior of the coatings revealed that storage modulus of the nanocomposites are higher than that of neat PUA, which is an indication of reinforcing effect of MgF2 nanoparticles. The damping factor curves demonstrated broadening and significant positive shifts (more than 33 °C) in glass transition temperature for the nanocomposites compared to neat PUA, providing additional evidence of strong interactions between MgF2 and PUA. Morphology and nanoparticle dispersion in the nanocomposites were also investigated. Contact angle measurements indicated improved wettability with increasing MgF2 content, reaching 44.4° for the nanocomposite containing 5 wt.% MgF2. [ABSTRACT FROM AUTHOR]

Many energy absorption applications utilize flexible polymeric foams for their viscoelastic properties. It is desired that the material will perform consistently across repeated compression cycles. This study examines the effect of fatigue at low strain rates on the viscoelasticity of open‐cell polyurethane foam. Six polyurethanes of the same base composition with two porosities (70% and 80%) and three chemical indexes (79i, 100i, and 121i) are tested. Large deformation cyclic compression of the foams is conducted on a universal testing system (UTS). These data are then post‐processed leveraging dynamic mechanical analysis Fourier transform rheology to characterize changes in the viscoelasticity of the materials over fatigue cycles. Results show that foams can increase or decrease in stiffness up to 10% over 104 cycles. Specifically, higher chemical index, higher excitation frequency, and larger excitation amplitude correlate with a more pronounced decrease in stiffness. Damping can also change by 15% and correlates with chemical index and excitation frequency. Consequently, the findings suggest that internal foam structure and bulk material properties as well as applied loading parameters affect the viscoelastic fatigue response of flexible polymeric foams. [ABSTRACT FROM AUTHOR]

Allyl ether naphthol resin (ANPF) was synthesized by introducing 1,5‐dihydroxynaphthalene and 2,7‐dihydroxynaphthalene into phenolic resin and was copolymerized with 4,4′‐bismaleimidodiphenylmethane resin (BDM) to obtain allyl ether naphthol‐modified bismaleimide resins (15‐ANPF‐BDM and 27‐ANPF‐BDM). The resulting thermal stability and glass transition temperature (Tg) were explored by thermogravimetric and dynamic mechanical analyses. The char yield of 15‐ANPF‐BDM at a temperature of 800°C was 46.0%. Additionally, the Tg of 15‐ANPF‐BDM was measured as 311°C, which is an increase of 44°C compared to that of c. The mechanical properties of the ANPF‐BDM/quartz fiber (Qf) composites were also investigated. The results reveal that ANPF‐BDM/Qf composites exhibit similar mechanical strength to APF‐BDM/Qf composites at room temperature. In addition, the mechanical properties of the ANPF‐BDM/ Qf composites demonstrated significant improvement in mechanical properties retained significantly improved at 200°C, with a 68% flexural strength retention and a 96% interlaminar shear retention of 15‐ANPF‐BDM/Qf composites. Thus, ANPF‐BDM/Qf composites exhibit outstanding mechanical properties at 200°C. [ABSTRACT FROM AUTHOR]

The paper provides new experimental evidence for vulnerable artifacts on the dependence of failure strain on the loading rate corresponding to typical environmental loads lasting between hours and months. Animal glue-based ground was chosen for this study as an easily available, hygroscopic and brittle material as well as due to its abundance in collections and its relevance when discussing the risk of mechanical damage to objects. Gesso specimens were tested using dynamic mechanical analysis and tensile testing at different frequencies, under a variety of loading rates and temperatures. The time-temperature superposition principle was used to predict the material response to slow deformations (lasting hours to months) that are otherwise inaccessible on laboratory timescales. The results demonstrate that brittle materials such as animal glue-based grounds do not benefit from longer cycles of applied loads as failure strain is not time-dependent within the investigated timescale. [ABSTRACT FROM AUTHOR]

Aiming at the requirements of strong mobility and high flexibility of rescue and relief mobile pump trucks, this paper designs a new type of mobile pump truck frame based on existing mobile vehicle frame models. The materials used for the frame are 40Cr and Q235, and the finite element method is utilized to carry out static mechanical analysis and dynamic characteristic analysis. Simultaneously utilizing topology optimization and multi-objective genetic algorithm to optimize the design of the frame structure. The results show that the optimized pump truck frame can meet the strength design requirements of four typical working conditions: full load bending, full load torsion, emergency turning and emergency braking, while avoiding resonance phenomena caused by road surface and diesel engine vibration. Compared with the original frame model, the weight of the optimized frame is reduced by 87.88 kg, with a weight reduction rate of 10.89%, realizing the lightweight design requirements. [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]

This study investigated the thermal and mechanical properties of polyurethane foam (PUF) sandwich panels reinforced with varying amounts of clay nanoparticles (0, 0.5, 1 and 2 wt%) fabricated using the compression molding process. However, these composites were fixed to cores with a honeycomb structure. The morphology of PUF sandwich panels reinforced with clay nanoparticles was examined by scanning electron microscopy (SEM). The presence of clay nanoparticles in the honeycomb structure let to a reduction in cell size and an increase in the number of cells per unit volume. The impact of clay nanoparticles on the thermal properties of PUF reinforced with clay nanoparticles was investigated using thermogravimetric and dynamic mechanical thermal analysis (DMTA). The results indicated that the incorporation of clay nanoparticles as reinforcement enhanced the thermal properties of the PUF sandwich panel samples. Mechanical characterization technique including compression, three-point bending and drop weight impact tests displayed that the PUF reinforced with 1 wt% clay nanoparticles exhibited the most significant improvement in mechanical properties. [ABSTRACT FROM AUTHOR]

This study focuses on polyamide 6/organo-modified montmorillonite (PA6/OMMT) nanocomposites as potential liner materials, given the growing interest in enhancing the performance of type IV composite overwrapped hydrogen storage pressure vessels. The mechanical properties of PA6/OMMT composites with varying filler concentrations were investigated across a temperature range relevant to hydrogen storage conditions (−40 °C to +85 °C). Liner collapse, a critical issue caused by rapid gas discharge, was analyzed using an Ishikawa diagram to identify external and internal factors. Mechanical testing revealed that higher OMMT content generally increased stiffness, especially at elevated temperatures. The Young's modulus and first yield strength exhibited non-linear temperature dependencies, with 1 wt. per cent OMMT content enhancing yield strength at all tested temperatures. Dynamic mechanical analysis (DMA) indicated that OMMT improves the storage modulus, suggesting effective filler dispersion, but it also reduces the toughness and heat resistance, as evidenced by lower glass transition temperatures. This study underscores the importance of optimizing OMMT content to balance mechanical performance and thermal stability for the practical application of PA6/OMMT nanocomposites in hydrogen storage pressure vessels. [ABSTRACT FROM AUTHOR]

Metal Fused Filament Fabrication provides a simple and cost-efficient way to produce dense metal parts with a homogenous microstructure. However, current limitations include the use of hazardous and expensive organic solvents during debinding for flexible filaments the stiffness of filaments made from partly water-soluble binder systems. In this study, the influence of various additives on different partly water-soluble binder systems, with regard to the flexibility and properties of the final parts, was investigated. Furthermore, a method using dynamic mechanical analysis to quantify the flexibility of filaments was introduced and successfully applied. For the first time, it was possible to produce flexible, partly water-soluble filaments with 60 vol.% solid content, which allowed the 3D printing of complex small and large parts with a high level of detail. After sintering, density values of up to 98.9% of theoretical density were achieved, which is significantly higher than those obtained with existing binder systems. [ABSTRACT FROM AUTHOR]

This study aims to examine the 50/50 polypropylene/polyamide 6 (iPP/PA6) system molded under confined flow conditions, both in its original state and after being modified by two different interfacial agents. This study provides two main insights. Firstly, it focuses on a polymer blend close to phase inversion. Secondly, it investigates the impact of using two different types of interfacial agents (derived from polymer waste) to enhance the compatibility between iPP and PA6. Dynamic Mechanical Analysis (DMA) has been employed to achieve these objectives. It is important to note that the investigation of the 50/50 iPP/PA6 system is a crucial focus predicted in previous studies, where a series of mechanical properties were evaluated using Box–Wilson design of experiments (DOEs) over the whole compositional range on the iPP/PA6 binary system. Thus, two interfacial modifiers, namely succinic anhydride (SA)-grafted atactic polypropylene with terminal, side, and bridge SA grafts (aPP-SASA) and succinyl-fluoresceine (SF) with bridge succinic anhydride grafting atactic polypropylene (aPP-SFSA), were employed. The authors obtained and characterized these agents. The quantity of these agents used in the blend was identified as a critical coordinate in prior studies conducted by the authors. The processing method used, compression molding under confined conditions, was chosen to minimize any orientation effect on the emerging morphology. All characterization procedures were performed on samples processed by contour machining to retain the blend morphologies as they emerged from the processing stage. Results from WAXS and SAXS synchrotron tests concluded there were no changes in the crystal morphology of the iPP or the PA6 in the blends nor any co-crystallization process throughout the compositional range. These findings, and the long period fits on the PP crystalline phase for the fifty/fifty blends we are discussing, will support the present DMA study. Finally, the efficiency of these interfacial modifiers has been concluded, even in this unfavorable scenario. [ABSTRACT FROM AUTHOR]

Polymer materials have garnered significant attention due to their exceptional mechanical properties and diverse industrial applications. Understanding the glass transition temperature (Tg) of polymers is critical to prevent operational failures at specific temperatures. Traditional methods for measuring Tg, such as differential scanning calorimetry (DSC) and dynamic mechanical analysis, while accurate, are often time-consuming, costly, and susceptible to inaccuracies due to random and uncertain factors. To address these limitations, the aim of the present study is to investigate the potential of Simplified Molecular Input Line Entry System (SMILES) as descriptors in simple machine learning models to predict Tg efficiently and reliably. Five models were utilized: k-nearest neighbors (KNNs), support vector regression (SVR), extreme gradient boosting (XGBoost), artificial neural network (ANN), and recurrent neural network (RNN). SMILES descriptors were converted into numerical data using either One Hot Encoding (OHE) or Natural Language Processing (NLP). The study found that SMILES inputs with fewer than 200 characters were inadequate for accurately describing compound structures, while inputs exceeding 200 characters diminished model performance due to the curse of dimensionality. The ANN model achieved the highest R2 value of 0.79; however, the XGB model, with an R2 value of 0.774, exhibited the highest stability and shorter training times compared to other models, making it the preferred choice for Tg prediction. The efficiency of the OHE method over NLP was demonstrated by faster training times across the KNN, SVR, XGB, and ANN models. Validation of new polymer data showed the XGB model's robustness, with an average prediction deviation of 9.76 from actual Tg values. These findings underscore the importance of optimizing SMILES conversion methods and model parameters to enhance prediction reliability. Future research should focus on improving model accuracy and generalizability by incorporating additional features and advanced techniques. This study contributes to the development of efficient and reliable predictive models for polymer properties, facilitating the design and application of new polymer materials. [ABSTRACT FROM AUTHOR]

This study investigates the enhancement of polylactic acid (PLA) properties through the incorporation of graphene nanoplatelets (GNPs) and carbon black (CB) for applications in 3D printing and injection molding. The research reveals that GNPs and CB improve the electrical conductivity of PLA, although conductivity remains within the insulating range, even with up to 10% wt of nanoadditives. Mechanical characterization shows that nanoparticle addition decreases tensile strength due to stress concentration effects, while dispersants like polyethylene glycol enhance ductility and flexibility. This study compares the properties of materials processed by injection molding and 3D printing, noting that injection molding yields isotropic properties, resulting in better mechanical properties. Thermal analysis indicates that GNPs and CB influence the crystallization behavior of PLA with small changes in the melting behavior. Dynamic Mechanical Thermal Analysis (DMTA) results show how the glass transition temperature and crystallization behavior fluctuate. Overall, the incorporation of nanoadditives into PLA holds potential for enhanced performance in specific applications, though achieving optimal conductivity, mechanical strength, and thermal properties requires careful optimization of nanoparticle type, concentration, and dispersion methods. [ABSTRACT FROM AUTHOR]

The focus of this study is on the nonlinear mechanical properties of epoxy and epoxy-based nanocomposites, exploring frequency and strain amplitude dependency. Nanocomposite samples of epoxy are reinforced with fumed silica (FS), halloysite nanotubes (HNT) and Albipox 1000 rubber (Evonik) nanoparticles. Considering these particles have different geometries and stiffnesses, they are expected to have significantly different influences on the mechanics of the resulting composite. To enhance the reliability of the results and to reveal the impact of nanofillers on the mechanics of the material more distinctly, the manufacturing process is designed to be the same for all the specimens within the same material groups to eliminate the effects of the manufacturing process. The comprehensive characterization process consists of Fourier-Transform InfraRed Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Dynamic Mechanical Analysis (DMA). The DMA tests are designed so that the material properties are measured depending on the vibration frequency and strain amplitude. Finally, the characterized nonlinear dynamic properties of these nanocomposites are used as the input material properties into a numerical model. In this simulation, a cantilever beam with representative nonlinear material properties, for these nanocomposites, is created, as example and its forced response is plotted under the same levels of excitation in the frequency domain. Key effects of the different nanofillers are identified using the resonance behavior, primarily focusing on the stiffness and damping of the epoxy-based nanocomposites. These experimental and numerical procedures followed show the significant impact of the nanoparticle reinforcements on the nonlinear nature of these epoxy-based composites. [ABSTRACT FROM AUTHOR]

In this study, a sustainable biocomposite foamed recycled high-density polyethylene (rPE) with agave fiber at different compositions (0, 10, 20, and 30 wt%) with and without compatibilizer and a blowing agent were prepared using a twin-screw extruder, demonstrating an innovative use of waste materials. Samples for static and dynamic mechanical analysis (DMA) tests were prepared by injection molding. Additionally, characterization by capillary rheology, Fourier transform infrared spectroscopy (FTIR), and morphological studies was performed. For the prepared composites, the viscosity increases, while the melt flow index decreases with fiber content. Tensile and flexural properties increase with fiber content. For the composite with 30 wt% of fiber, the tensile modulus and the flexural modulus increased by 54% compared with pure recycled HDPE, while the tensile and flexural strength for this composition increased by 8.7% and 33%, respectively. The same trends are obtained by means of the DMA study, where the storage modulus of the modified composite with 30 wt% of agave fiber increased 70% compared with that of recycled HDPE at 20 °C. The improvements in properties obtained with agave fiber and the compatibilizer, show tangible recovery ways for foamed recycled HDPE. This work not only addresses the critical need for sustainable material options, but also contributes to the circular economy by valorizing agricultural and post-consumer waste. The potential applications of this biocomposite are broad, including lightweight building materials and automotive components, where sustainability and material performance are increasingly a priority. [ABSTRACT FROM AUTHOR]

Graphene has intriguing electrical, mechanical, thermal and biological properties that are being investigated for use in composites, modern electronics, membranes, and in the industry. Also, graphene has huge biological applications. Hydroxypropyl methylcellulose (HPMC) is a widely used bio-polymer effective for various biomedical applications. As a filler in this polymer matrix, graphene oxide (GO), reduced graphene oxide (RGO) and silver (Ag) nanoparticles (NPs) can be used to improve various properties of the matrix. They are also beneficial for bio-applications like drug delivery, the production of reactive oxygen species (ROS) and the antimicrobial properties of nanocomposite films. Here we synthesize a series of polymer nanocomposites taking GO, RGO and Ag NPs as a filler by the solution mixing method and explore the comparative biological application of such composites. We choose Ag NPs as it has the superior potential for multiple drug resistance. X-ray diffraction, Fourier-transform infrared and scanning electron microscope studies are used to describe how nanocomposites are formed. Energy-dispersive X-ray and dynamic mechanical analyzer analyses were also done to check elemental percentage in nanocomposite films and mechanical properties, respectively. To check several fruitful applications, antimicrobial properties, ROS generation and in-vitro drug release study of nanocomposite films with the loading of Ketorolac Tromethamine were also performed. [ABSTRACT FROM AUTHOR]

Thanks to its highly crystalline structure and excellent thermal, optical, electrical and mechanical properties, carbon and its derivatives are considered the preferred reinforcement material in composites used in many industrial applications, especially in the forest and forest products sector, including oil, gas and aviation. Since hydroxyethyl cellulose (HEC) is a biopolymer, it has poor mechanical and thermal properties. These properties need to be strengthened with various additives. This study aims to improve the thermal and mechanical properties of hydroxyethyl cellulose by preparing hydroxyethyl cellulose/activated carbon (HEC/AC) composite materials. With this study, composites were obtained for the first time and their mechanical properties were examined using a 3D numerical modeling technique. The thermal stability of the prepared composite materials was investigated via thermal gravimetric analysis (TGA). The samples were heated from 30 °C to 750 °C with a heating rate of 10 °C/min under a nitrogen atmosphere and their masses were measured subsequently. The mechanical properties of the composites were investigated via the tensile test. The viscoelastic properties of the composite films were determined with dynamic mechanical thermal analyses (DMTA) and their morphologies were examined with scanning electron microscopy (SEM) images. According to the results, the best F3 sample (films containing 3 wt.% activated carbon) had an elastic modulus of 168.3 MPa, a thermal conductivity value of 0.068 W/mK, the maximum mass loss was at 328.20 °C and the initial storage modulus at 30 °C was 206.13 MPa. It was determined that the hydroxyethyl cellulose composite films containing 3 wt.% activated carbon revealed the optimum results in terms of both thermal conductivity and viscoelastic response and showed that the obtained composite films could be used in industrial applications where thermal conductivity was required. [ABSTRACT FROM AUTHOR]

This study presents the preparation, hydrogel kinetics, and mechanical analysis of Boron Nitride (BN) reinforced PVA/PVP/PEO‐BN hydrogel composite films using Polyvinyl alcohol (PVA), Polyvinyl pyrrolidone (PVP), and Polyethylene oxide (PEO) commercial polymers. Dynamic mechanical analysis tests reveal that PVA90PEO5PVP5‐BN composite films exhibit plastic‐viscoelastic behavior under a maximum force of 18 N. The Young's Modulus values for PVA90PEO5PVP5, PVA90PEO5PVP5‐BN%10, and PVA90PEO5PVP5‐BN%20 are 0.22, 0.32, and 0.44 MPa, respectively. The highest % Strain value is observed in PVA90PEO5PVP5‐BN%20, reaching 279.80%. In the hydrogel kinetics study, Schott's and Fickian models are utilized. The regression from the Fickian model is quite low, with exponential diffusion index, n, values lower than 0.5, indicating a classical Fickian water diffusion mechanism. Schott's model provides graphs with significantly higher regression compared to the Fickian model. The results indicate compatibility with the other model and confirm the presence of water‐based diffusion. Equilibrium swelling values (Se, g H2O/g gel) are 6.71, 7.03, and 7.91 for PVA90PEO5PVP5, PVA90PEO5PVP5, PVA90PEO5PVP5‐BN%10, and PVA90PEO5PVP5‐BN%20, respectively. Differential Scanning Calorimetry (DSC) analysis results show that the glass transition temperatures, Tg, are 52.37, 60.20, and 63.05°C for PVA90PEO5PVP5, PVA90PEO5PVP5‐BN%10, and PVA90PEO5PVP5‐BN%20, respectively. [ABSTRACT FROM AUTHOR]

Polypropylene carbonate (PPC) is a promising candidate of substrate materials used for human wearable devices due to its excellent ductility and biocompatibility. However, PPC is prone to be deformed, thus resulting in poor shape recovery property. One effective solution is to construct composites. In this work, poly (tannic acid) with Fe3+ (FPTA) @ graphene oxide (GO) was added to fabricate FPTA@GO/PPC composites. The results show that FPTA@GO can construct a tight network of hydrogen bonds into PPC to improve shape memory and self‐healing properties. By varying the FPTA@GO content, the composites exhibit tunable shape memory property. Dynamic mechanical analysis confirms that FPTA@GO/PPC composites show better shape memory properties compared with pure PPC. 5 wt% FPTA@GO/PPC composite demonstrates superior shape fixation ratio (Rf = 99%) as well as superior shape recovery ratio (Rr = 94%) in 37°C. Moreover, 5 wt% FPTA@GO/PPC composite possesses great self‐healing efficiency of 81% and tensile strength (17.2 MPa). The UV absorption capacity of 5 wt% FPTA@GO/PPC is increased by 150% (far and mid‐UV regions) and 400% (near‐UV region) compared with pure PPC. Thus, FPTA@GO/PPC composites have potential applications in developing shape memory, self‐healing, and UV‐resistant materials for human wearable devices. [ABSTRACT FROM AUTHOR]

This study presents an antimicrobial polymeric material comprising cellulose nanocrystals (CNCs) grafted with an antimicrobial oligomer, polyhexamethylene guanidine hydrochloride (PHGH). A one‐pot reaction is implemented to graft PHGH onto CNCs, creating a non‐leaching and nano‐sized antimicrobial additive (mCNC). The mCNC is subsequently incorporated into a model polymer, polylactic acid (PLA), with concentrations of 2.5 to 10 wt.% and tested for its antimicrobial activity during dynamic and static contact with Escherichia coli and Bacillus subtilis bacteria. The grafting of PHGH onto CNC is confirmed with Fourier transform infrared spectroscopy (FTIR), X‐ray spectroscopy (XPS) and elemental analysis. The effect of mCNC incorporation at various loading levels on the morphology and physicomechanical properties of PLA is investigated with polarized optical microscope (POM), scanning electron microscope (SEM), dynamic mechanical analysis (DMA), tensile testing, and differential scanning calorimetry (DSC). In terms of the antimicrobial action, the films exhibited potent efficacy against Gram‐positive bacteria (B. subtilis), with growth inhibition of 3.97 to 4.66‐log reduction. However, 10 wt.% of mCNC loading is needed to achieve a significant bacterial inhibition (>6.24‐log) of the Gram‐negative bacteria (E. coli). Overall, the incorporation of PHGH grafted CNCs in polymers provided a non‐leaching antimicrobial film that has potential application in food packaging. [ABSTRACT FROM AUTHOR]

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We report unique two-step strain glass transition toward different local strain states in NiTi, i.e. R and B19′ strain glasses. This unique transition is evidenced by dynamic mechanical analysis and in-situ HR-TEM. A comprehensive phase diagram is established to illustrate diverse transition pathways and corresponding tunable superelastic properties. This pathway exploits the integrated transition of different phases, lowering the transition energy barrier, yielding superelasticity with large recoverable strain (6%), ultralow modulus (24 GPa) and robust cyclic and wide-temperature stability. Our investigation provides fresh insights into continuous transition pathways among different strain glass states to achieve exceptional properties in shape memory alloys. [ABSTRACT FROM AUTHOR]

An inexpensive membrane with high proton conductivity and high fuel cell performance, which can be an alternative to Nafion for PEMFC (Proton exchange membrane fuel cell), will overcome the obstacle to widespread commercialization of fuel cells due to high cost. For this purpose, SPEEK (sulfonated polyether ether ketone)-PVA (polyvinyl alcohol) blend membranes with colloidal silica additives were synthesized in this study. Ludox AS-40 was used as the colloidal silica source and the blend membrane was prepared by solution casting method. Water uptake capacity, swelling property, size change, dynamic mechanical analysis, ion exchange capacity, AC impedance analysis, hydrolytic and oxidative stability experiments of the synthesized Ludox additives blend membranes for fuel cell application were carried out, and the membranes were also characterized by FTIR (Fourier transform infrared) analysis. While the water uptake capacities of SPEEK/PVA membranes containing 1% Ludox, 5% Ludox, and 10% Ludox at room temperature were found to be 14.08%, 14.84%, and 16.6%, respectively, the water uptake capacities at 80oC increased to 14.73%, 15.17%, and 17.11%. The proton conductivities of 1% Ludox, 5% Ludox and 10% Ludox doped SPEEK/PVA membranes at 80oC were 0.25 S/cm, 0.56 S/cm, and 0.65 S/cm, respectively. Similarly, ion exchange capacities were determined to be 1.41 meq/g, 1.63 meq/g, and 1.71 meq/g, respectively. All Ludox-added membranes exhibited excellent hydrolytic stability, retaining approximately 88% of their mass after 650 h. In addition, in oxidative stability experiments carried out in 4 ppm Fe+ 2 at 80oC, the 10% Ludox-added membrane exhibited the highest weight loss of 88.8% at the end of 24 h, while the 5% Ludox-additive membrane retained 91.6% of its total weight. Considering the proton conductivity and longevity tests of the synthesized membranes, they are thought to be promising structures. [ABSTRACT FROM AUTHOR]

In recent years, thermoset elastomers, particularly polyesters derived from the polycondensation of glycerol and non-toxic diacids, have garnered significant interest. This study focuses on the synthesis of poly(glycerol-co-diacids) polymers using varying molar ratios of glycerol (G), sebacic acid (S), and succinic acid (Su). Seven distinct ratios were investigated (PGS (1:1), PGSSu (1:0.9:0.1), PGSSu (1:0.8:0.2), PGSSu (1:0.5:0.5), PGSSu (1:0.2:0.8), PGSSu (1:0.1:0.9) and PGSu (1:1)). The resulting polymers were analyzed using Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), dynamic mechanical analyses (DMA), tensile tests, scanning electron microscopy (SEM), gel fraction and degree of swelling determination. Among the synthesized polymers, PGS (1:1) and PGSu (1:1) exhibited superior mechanical robustness than the polymers obtained by mixing diacids. The results show that the incorporation of succinic acid in the synthesis of the polymers progressively led to rougher surfaces and a reduction in thermal resistance compared to PGS (1:1). PGSu (1:1) showed the highest surface roughness and the lowest thermal resistance. The glass transition temperature (Tg) for these elastomers ranged from − 30 °C to 30 °C. Additionally, higher ratios of succinic acid led to increased polymer density and less degree of swelling. The gel fraction of these polymers ranged from 70 to 95%. PGS (1:1) with the lowest and PGSu (1:1) with the highest gel fraction, respectively. [ABSTRACT FROM AUTHOR]

This study was focused on developing and evaluating the impacts of wood and graphite fillers on an E-glass fibre-reinforced polyester composite. The fillers employed in this study include teak, casuarina, psuedon wood dust, graphite, and hybrid fillers such as casuarina and graphite fillers. They tested for tension, flexural, impact, hardness, and dynamic mechanical analysis. In the current work, the optimum loading level is 15 wt% which was determined through testing at various loading levels. The experimental results have shown that the mechanical, physical, and thermomechanical properties of glass fiber reinforced polyester composites improvement mechanism analysis depend upon chemically treated wood dust fillers by avoiding surface delamination during fabrication. By using the hand layup method, composites were created by maintaining the fibre constant while distributing the fillers following the rule of mixture; a hybrid composite has a filler distribution of 1:1. Hybrid composite has exhibited increased flexural strength and hardness by 72.77%, 63.33% compared to casuarina wood of 15 wt% by avoiding incompatibility of casuarina wood filler with the resin. The glass transition value of the hybrid composite was increased by 1.4% compared to the above said casuarina wood composite, making it a more thermally resistant material. The hardness of the hybrid composite has increased by 2.78% compared to the teak wood of 15 wt% composite. [ABSTRACT FROM AUTHOR]

Elastomer O-ring seals are used in many technical applications and their requirements are becoming increasingly challenging for high-pressure applications like hydrogen storage systems. We analyze the performance of such seals at low temperatures and highlight the essential effects of primary leakage. Linear viscoelastic material modeling is described and defined with the help of Dynamic Mechanical Thermal Analysis (DMTA), Time-Temperature Superposition Principle (TTSP), and the shift function of Williams-Landel-Ferry (WLF) by assuming thermo-rheological simple material behavior. Numerical calculations and experimental validation are done for strain-rate dependent uniaxial tensile tests, Temperature Retraction (TR), Compression Set (CS), and specific leakage tests with O-rings. Thanks to Finite Element Analysis (FEA) it is possible to identify the most significant influences on the sealing tightness. Thermal shrinkage and the increasingly limited recovery of elastomer O-rings are mainly responsible for primary leakage at low temperatures and can be enforced by time-temperature dependent stress relaxation and manufacturing tolerances. • The elastomer material 80FVMQ 567 was characterized via several material tests. • Linear viscoelastic material modeling was described in detail (WLF, TTSP, Prony) and implemented in the simulation. • Finite element simulations were validated with key O-Ring experiments at different temperatures. • The generation of primary leakage could be shown with numerical analyses and experiments. • The essential effects of primary leakage were identified and segregated with Finite Element Analyses and experiments. [ABSTRACT FROM AUTHOR]

Vibration and noise severely affect the operation of mechanical equipment and is also detrimental to human health. Therefore, the development of high performance damping materials is crucial. However, current methods to improve damping properties often come at the expense of mechanical properties, resulting in inferior mechanical performance of materials. In order to address the issue of imbalance between damping properties and mechanical properties in polyurethane damping elastomers. In this study, polyester dangling chains containing polar groups are synthesized and introduced into polyurethane. The obtained polyurethane exhibited an effective damping temperature range of 154 °C (−54 °C to 100 °C) and a tensile strength of 15.82 MPa. Furthermore, dynamic mechanical analysis and broadband dielectric relaxation spectroscopy are combined to investigate the influence of polar dangling chains on the structure and properties of polyurethane. The degree of microphase separation increases after the introduction of polar dangling chains, indicating enhances intermolecular interaction forces, facilitating the formation of hydrogen bond between the main chain and dangling chains, thereby increasing molecular chain friction and energy dissipation. This work overcomes the challenge of balancing the damping and mechanical properties of polyurethane, providing a new strategy for designing high performance polyurethane damping elastomers. [ABSTRACT FROM AUTHOR]

In this research, an investigation was conducted to ascertain the impact of boron carbide (B4C) microparticles on soft and hard armor configurations, utilizing two distinct high‐performance fabrics namely, Kevlar and Ultra‐high Molecular Weight Polyethylene (UHMWPE), also this work discerned the optimal fabric for protection against dagger attacks and 9 mm full metal jacket (FMJ) projectiles. Initially, rheological tests on four shear thickening fluid (STF) samples revealed that 70% of nano‐silicate (SiO2) content was the optimal ratio. Besides, scanning electronic microscope (SEM) tests showed that B4C affected the nano‐silicate dispersion. Hence, the use of STF as a matrix, led to complete protection in low‐velocity stab test and behavior improvement when subjected to NIJ ballistic test for both fabric types. On the other hand, the dynamic mechanical analysis (DMA) of the thermosetting epoxy resin‐based composites reinforced by B4C indicated that the 10% ratio offered maximum rigidity, resulting in improved ballistic performance. This study revealed that Kevlar fabrics exhibit superior behavior in soft protection, while UHMWPE hard composite display further rigidity against high‐velocity impacts. Overall, this work contributes novel insights into the efficiency of B4C integration within soft and hard armor configurations using two ballistic fabrics, highlighting their performance characteristics in ballistic shielding. Highlights: Investigation of B4C microparticles: The research examines the impact of B4C microparticles on soft and hard armor configurations.High‐performance fabrics: Kevlar and UHMWPE uses.The use of STF as a matrix for soft and thermosetting epoxy resin for hard armor: enhanced composite performance.Low‐velocity and high‐velocity impact tests investigations; microparticles B4C incorporation: superior mechanical characteristics.Remarkable energy absorption: promising shielding uses. [ABSTRACT FROM AUTHOR]

Polymer alloying is particularly important due to the possibility of choosing a wide range of materials and the ability to design a product with desired properties. In case of incompatibility between the components, the resulting alloy cannot meet the set of desired properties and shows poor performance. In this research, alloys of polyvinyl chloride and polylactic acid were prepared in an internal mixer and nanoclay and maleic anhydride‐grafted styrene‐ethylene/butylene‐styrene (SEBS‐g‐MAH) compatibilizer were used to improve the properties. In order to investigate the morphology and phase distribution of polylactic acid, scanning electron microscope images were taken. Tensile and dynamic mechanical thermal analysis tests were performed to evaluate the properties of the samples. The scanning electron microscope test images show the improvement of system uniformity by adding compatibilizer to the alloy. Adding nanoclay to the alloy increased the storage modulus and uniformity of the system. An increase in glass transition temperature and storage modulus was observed in the samples containing compatibilizer, and the uniformity of the system was also improved. The tensile test results showed that by adding nanoclay up to 3 % by weight, the tensile strength and Young′s modulus increase. Addition of compatibilizer up to 5 % by weight increased the physical and mechanical properties. [ABSTRACT FROM AUTHOR]

Highlights The composites of polybenzoxazine (PBZ) containing functionalized plasma treatment basalt fibers (fP‐BFs) were fabricated through in‐situ polymerization‐mixing technique. fP‐BFs is an effective reinforcement material that can improve the mechanical, thermal, and interfacial properties of composites. Surface activation of fP‐BFs can be enhanced through plasma modification, which improves the interaction between fP‐BFs and 3‐aminopropyltriethoxysilane. A systematic study on fP‐BFs/PBZ composite showed that a processing power of 300 W, a processing time of 5 min, and a fiber content of 9% can achieve good comprehensive mechanical properties. Thermogravimetric analysis results showed that fP‐BFs‐7/PBZ has the highest thermal stability, and its carbon residue rate, decomposition temperature and thermal decomposition activation energy are 36.80%, 452.2 °C and 133.56 kJ/mol, respectively. The dynamic mechanical analysis experiment showed that the addition of fP‐BFs improved the Tg of the composites. Among them, fP‐BFs‐5/PBZ showed the highest Tg, reaching 233.2 °C. Plasma treatment produced multi‐level structure of basalt fibers (fP‐BFs). Polybenzoxazine (PBZ)/fP‐BFs composites showed excellent performance. Interfacial bonding mechanism between fP‐BFs and PBZ was elucidated. Interfacial interactions between BFs and PBZ contributed to property enhancement. This work provided a green fabrication strategy of PBZ composites. [ABSTRACT FROM AUTHOR]

Dynamic mechanical spectroscopy is a common analysis for polymers. Rectangular specimens are usually used for measurement in the solid state due to their easy designing. However, in reason of the non‐symmetric shape of sample, rectangular specimens do not experience linear stress on their all body, leading to overestimation of shear modulus. Corrections are required to determine the right shear modulus. In this present work, straight shear modulus determination is carried out using specimens with a cylindrical shape. The reliability of the technique is described on a biosourced polymer materials made of thermoplastic starch, plasticized by glycerol, choline chloride/urea mixture (ChCl/U), 1‐ethyl‐3‐methylimidazolium chloride ([EMIM]Cl) and 1‐ethyl‐3‐imidazolium acetate ([EMIM]Ac). The technique is shown to be particularly interesting to avoid any additional shaping of the specimens prior to measurements, that can be detrimental to their properties (evaporation, degradation). A comparison between cylinder and rectangular specimen has also been made to illustrate the interest of cylinder clamping on biosourced polymer material. [ABSTRACT FROM AUTHOR]