Search Results (3,459)

Nanofibers, as nucleating agents, can significantly alter the nucleation and growth dynamics of polymer crystallization, thereby modulating the morphology and structure of crystals to enhance mechanical performance of the materials. In this study, the effects of nanofibrillar nucleating agent 1,3:2,4-di(3,4-dimethylbenzylidene) sorbitol (DMDBS) content, melting temperature, and injection speed on the crystallization behavior and mechanical performance of isotactic polypropylene (iPP) were systematically investigated. The incorporation of DMDBS significantly increased the number of iPP nuclei, reduced crystal size and raised the onset crystallization temperature by approximately 11 °C. Concurrently, the tensile strength and elastic modulus of injection-molded iPP samples improved by 15% and 55%, respectively. However, a rise in the melting temperature led to a decrease in the crystallinity, tensile strength, elastic modulus, and impact strength of both neat iPP and iPP/DMDBS samples. With the increase in injection speed, the tensile strength and elastic modulus of iPP/DMDBS samples increased. During the crystallization process, DMDBS crystallizes prior to the iPP melt, forming the nanofibrillar network that effectively reduced the energy barrier for iPP crystal nucleation. Furthermore, under the influence of shear forces during processing, the presence of these nanofibrillar networks promoted the formation of oriented crystalline structures, which in turn contributed to the enhanced tensile strength and elastic modulus observed in iPP samples. Full article

Structural composite materials are being used more than ever in aeronautics, automotive and naval, or in renewable energies fields. To reconcile the contradictory needs for higher performances and lower costs, it is crucial to ensure the real-time monitoring of as many features as possible during the manufacturing process to feed a digital twin able to minimise post-fabrication controls. For thermoset composites, little information is available regarding the evolution of the polymer’s core properties during infusion and curing. The local kinetics of reticulation, in several areas of interest across the thickness of a structural composite part, are valuable data to record and analyse to guarantee the materials’ performances. This paper investigates a novel strategy curing in the core of an epoxy matrix with crosslinkable quantum-resistive nanocomposite sensors (xQRS). First, the electrical behaviour of the sensor during isothermal curing is considered. Then, the influence of the dynamic percolation and the epoxy crosslinking reaction on the resistance is examined. The evidence of a relationship between the curing state of the resin and the evolution of the xQRS resistance makes its use in the process monitoring of thermoset composites promising, especially in cases involving large and thick parts. Full article

This study introduces a cost-effective solution and sensor arrays for the multipoint liquid-level measuring sensor based on an intensity modulation technique. The sensor structure is based on the twisting of two fibers and creates cascading to achieve a multipoint detection. Three sensors are fabricated on a single illuminated polymer optical fiber. The twisting creates side-coupling between two fibers, and the coupled power is attenuated when liquid emerges in the coupled region. Each sensor has its own output source, which is connected to the power meter. When the liquid-level increases, the coupled power is continuously decreased. The multipoint liquid-level sensor is theoretical and experimentally tested. The experimental results show that sensors have a good response and linearity. The sensors are able to measure the liquid-level up to 12 cm and have a sensitivity of about 0.2726 μW/cm, 0.1715 μW/cm, and 0.1281 μW/cm, respectively. The different flow rate (50 mL/min–300 mL/min) is also analyzed to validate the dynamic response of the sensor. The sensor demonstrates a high sensitivity and resolution in the liquid-level detection. Meanwhile, the liquid-level variation is individually and simultaneously measured. The system does not require any decoupling technique as the system relies on a single LED source, and the coupled power is individually measured from each power meter. The system represents a significant advancement in precise liquid-level sensing technology, as the system has advantages of a flexible, durable, cost-effective, and active response with respect to changes in the liquid-level. Full article

Epoxy asphalt is a superior polymer-modified asphalt material; however, significant differences in physicochemical properties, such as solubility parameters and dielectric constants, between epoxy resin and asphalt have led to compatibility issues that hinder its development. This study employed molecular dynamics simulations to investigate the effect of maleic anhydride-grafted styrene-butadiene-styrene (MAH-g-SBS) on the compatibility of epoxy asphalt. By analyzing parameters such as cohesive energy density, solubility parameters, energy distribution, interaction energy, radial distribution function, free volume fraction, and mean square displacement, the molecular mechanism underlying the enhanced compatibility was elucidated. The results indicate that the amphiphilic molecular structure of MAH-g-SBS significantly improves the thermodynamic compatibility between asphalt and epoxy resin, enhances interfacial affinity and stability, reduces the system’s total interaction and nonbonded energies, facilitates the dispersion and permeation of epoxy molecules into asphalt, and increases molecular mobility, thereby comprehensively enhancing the compatibility of the epoxy asphalt blend. Segregation tests and fluorescence microscopy further verified the simulation results, demonstrating that MAH-g-SBS improves the storage stability and phase uniformity of the epoxy asphalt system. Full article

Knots are ubiquitous in polymers and biological macromolecules such as DNA and proteins, yet their behavior and functionality are still not sufficiently explored. Here we investigate the impact of Poiseuille flow on simple knots in flexible polymers placed in a quasi-rectangular micro-channel by systematically varying the flow strength for different chain lengths. Hydrodynamic interactions are accounted for by means of Multi-Particle Collision Dynamics (MPCD). We find that initially loosely localized knots in polymer coils typically tighten under shear to several segments beyond a certain body force threshold. At higher shear rates, intermittent transition from chain stretching to tumbling is observed which correlates with strong fluctuations in the knot size. Somewhat unexpectedly, our results indicate that the influence of channel width on tightening steadily increases with growing width even at equal mean shear rate $\overline{\dot{\gamma }}$. Full article

Next-generation pilot suits are evolving into intelligent, adaptive platforms that integrate advanced polymeric materials, smart textiles, and on-body artificial intelligence. High-performance polymers have advanced in mechanical strength, thermal regulation, and environmental resilience, with fabrication methods like electrospinning, weaving, and 3D/4D printing enabling structural versatility and sensor integration. In particular, functional nanomaterials and hierarchical nanostructures contribute critical properties such as conductivity, flexibility, and responsiveness, forming the foundation for miniaturized sensing and integrated electronics. The integration of flexible fiber-based electronics such as biosensors, strain sensors, and energy systems enables real-time monitoring of physiological and environmental conditions. Coupled with on-body AI for multimodal data processing, autonomous decision-making, and adaptive feedback, these systems enhance pilot safety while reducing cognitive load during flight. This review places a special focus on system-level integration, where polymers and nanomaterials serve as both structural and functional components in wearable technologies. By highlighting the role of nanostructured and functional materials within intelligent textiles, we underline a potential shift toward active human–machine interfaces in aerospace applications. Future trends and advancements in self-healing materials, neuromorphic computing, and dynamic textile systems will further elevate the capabilities of intelligent pilot suits. This review discusses interdisciplinary strategies for developing pilot wearables capable of responding to real-time physiological and operational needs. Full article

Vascularization remains a critical challenge in tissue engineering, limiting graft survival, integration, and clinical translation. Although bioprinting enables spatial control over vascular architectures, many existing approaches prioritize geometric precision over biological performance. Bioprinted vasculature can be understood as a dynamic and time-dependent system that requires tissue-specific maturation. Within this framework, hydrogel systems act as active microenvironments rather than passive scaffolds. Hydrogel platforms vary from natural matrices and synthetic polymers to bioinspired or stimuli-responsive systems, each offering tunable control over stiffness, degradation, and biochemical signaling needed for vascular maturation. The design requirements of large and small vessels differ in terms of mechanical demands, remodeling capacity, and host integration. A key limitation in current models is the absence of time-resolved evaluation, as critical processes such as lumen formation, pericyte recruitment, and flow-induced remodeling occur progressively and are not captured by static endpoints. Advancements in bioprinting technologies are evaluated based on their capacity to support hydrogel-mediated vascularization across varying length scales and structural complexities. A framework for functional assessment is proposed, and translational challenges related to immunogenicity, scalability, and regulatory requirements are discussed. Such integration of hydrogel-driven biological cues and bioprinting fidelity is critical to advancing vascularized constructs toward clinical translation. Full article

The North American Thermal Analysis Society (NATAS) is pleased to announce its 51st Annual Conference, held jointly with the IX International Baekeland Symposium. This premier event unites scientists, practitioners, and students from academia, industry, and government to explore the forefront of materials science. The NATAS conference provides a dynamic forum for attendees to delve into the latest advancements in thermal analysis, rheology, and materials characterization. The technical program will highlight new developments in instrumentation and software, alongside practical applications across a wide range of industries. Concurrently, the Baekeland Symposium will showcase cutting-edge scientific, technical, and industrial innovations in the field of high-performance thermosetting polymers. The synergy of this joint meeting creates a unique platform for cross-disciplinary collaboration, fostering the exchange of novel ideas and sparking new research opportunities. Featuring technical presentations, poster sessions, and plenary lectures from renowned experts and emerging graduate students, the conference offers an ideal environment for networking and professional development. We invite you to join us to discover state-of-the-art techniques, discuss groundbreaking research, and connect with peers and leaders in the thermal and materials community. Full article

Biologically derived polymers, such as chitosan, have gained attention as sustainable alternatives to synthetic materials for food and biomedical applications. Fungal-derived chitosan offers notable advantages over crustacean-based chitosan, including a renewable origin and lower allergenic potential. In this study, chitosan was extracted from fungal biomass through a sequential process comprising demineralization, deproteinization, and deacetylation. The extracted material was characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), zeta potential measurement, dynamic light scattering (DLS), and color analysis. Compared to commercial chitosan, the fungal chitosan exhibited lower crystallinity and thermal stability, as well as a more porous surface morphology. Its degree of deacetylation and surface charge suggest promising potential for use in biodegradable films and functional materials. These findings highlight the feasibility of using fungal biomass as a sustainable and valuable source of chitosan for technological applications. Full article

Mouthguards are recommended for all sports that may cause injuries to the head and oral cavity. Custom mouthguards, made conventionally in the thermoforming process from ethylene vinyl acetate (EVA), face challenges with thinning at the incisor area during the process. In contrast, additive manufacturing (AM) processes enable the precise reproduction of the dimensions specified in a computer-aided design (CAD) model. The potential use of filament extrusion materials in the fabrication of custom mouthguards has not yet been explored in comparative studies. Our research aimed to compare five commercially available filaments for the material extrusion (MEX) also known as fused deposition modelling (FDM) of custom mouthguards using a desktop 3D printer. Samples made using Copper 3D PLActive, Spectrum Medical ABS, Braskem Bio EVA, DSM Arnitel ID 2045, and NinjaFlex were compared to EVA Erkoflex, which served as a control sample. The samples underwent tests for ultimate tensile strength (UTS), split Hopkinson pressure bar (SHPB) performance, drop-ball impact, abrasion resistance, absorption, and solubility. The results showed that Copper 3D PLActive and Spectrum Medical ABS had the highest tensile strength. DSM Arnitel ID 2045 had the highest dynamic property performance, measured with the SHPB and drop-ball tests. On the other hand, NinjaFlex exhibited the lowest abrasion resistance and the highest absorption and solubility. DSM Arnitel ID 2045’s absorption and solubility levels were comparable to those of EVA, but had significantly lower abrasion resistance. Ultimately, DSM Arnitel ID 2045 is recommended as the best filament for 3D-printing mouthguards. The properties of this biocompatible material ensure high-impact energy absorption while maintaining low fluid sorption and solubility, supporting its safe intra-oral application for mouthguard fabrication. However, its low abrasion resistance indicated that mouthguards made from this material may need to be replaced more frequently. Full article

We study the microstructural properties and state of hydration of aqueous low-molecular-weight poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) solutions and their dependence on polymer concentration and pH by means of detailed atomistic Molecular Dynamics (MD) simulations and experiments. For infinitely dilute solutions with a degree of polymerization of N = 30 at basic pH conditions, no temperature dependence is observed on the overall shape and state of hydration of the polyelectrolyte. This is supported by the experimental component of our work according to which the hydrodynamic radius, R_h, does not change dramatically with temperature. Small, but not drastic, changes are observed for solutions with longer PDMAEMA chains (N = 50, 70, and 110). Although the MD simulations demonstrate that temperature and salt do affect the strength of hydrophobic interactions between PDMAEMA and water, apparently these effects are not strong enough to cause drastic changes to the overall shape of the polymer. MD simulations also reveal that Na⁺ salt ions strongly interact with the oxygen atoms located at the side chain of the polyelectrolyte. While no significant changes in the global shape or state of hydration of the PDMAEMA chain are found, a strong dependence is revealed for the aggregation behavior of the polymer on temperature and salt in slightly more concentrated solutions. A structural transition from a collapsed coil to a stretched conformation is also observed as we move from basic to acidic pH conditions, which is strongly correlated with the degree of chain rigidity as a function of pH. Full article

Solvent-exchange-induced in situ forming gel (ISG) refers to a drug delivery system that transforms from a solution state into a gel or solid matrix upon administration into the body and exposure to physiological aqueous fluid. This study investigates the molecular behavior and phase inversion process of cellulose acetate butyrate (CAB)-based in situ forming gel (ISG) formulations containing moxifloxacin (Mx) or benzydamine HCl (Bz) as model drugs dissolved in N-methyl pyrrolidone (NMP) using molecular dynamics (MD) simulations and density functional theory (DFT) calculations. The simulations reveal a solvent exchange mechanism, where the diffusion of water molecules replaces NMP, driving the formation of the CAB matrix. Bz exhibited faster diffusion and a more uniform distribution compared to Mx, which aggregated into clusters due to its larger molecular size. The analysis of the root mean square deviation (RMSD) and radius of gyration confirmed the faster diffusion of Bz, which adopted a more extended conformation, while Mx remained compact. The phase transformation was driven by the disruption of CAB-NMP hydrogen bonds, while CAB–water interactions remained limited, suggesting that CAB does not dissolve in water, facilitating matrix formation. The molecular configuration revealed that drug–CAB interactions were primarily governed by hydrophobic forces and van der Waals interactions rather than hydrogen bonding, controlling the release mechanism of both compounds. DFT calculations and electrostatic potential (ESP) maps illustrated that the acetyl group of CAB played a key role in drug–polymer interactions and that differences in CAB substitution degrees influenced the stability of drug-CAB complexes. Formation energy calculations indicated that Mx-CAB complexes were more stable than Bz-CAB complexes, resulting in a more prolonged release of Mx compared to Bz. Overall, this study provides valuable insights into the molecular behavior of CAB-based Mx-, Bz-ISG formulations. Full article

Composite materials have been increasingly used in various branches of industry, transport, construction, and medicine—as well as in other sectors of the economy and science—in recent decades. A significant advancement in the improvement of composite material characteristics has been achieved through the use of nanoparticles, which substantially enhance the properties of the base material, whether it is the matrix or the reinforcing phase in hybrid composites. The broad application of polymers and polymer composites in many areas of engineering has had a significant impact on reducing friction and wear, improving the thermal characteristics of individual components and entire technical systems, enhancing electrical conductivity, reducing the specific weight of components, lowering noise and vibration levels, and ultimately decreasing fuel consumption, production costs, and the costs of operation and maintenance of technical systems. This paper explores the potential applications of polymer composites in various assemblies and components of conventional vehicles, as well as in hybrid and electric vehicles. Furthermore, their use in medicine and the defense industry is examined—fields in which some authors believe composites were first pioneered. Finally, aviation represents an indispensable domain for the application of such materials, presenting unique exploitation boundary conditions, including dynamic environmental changes such as variations in temperature, pressure, velocity, and direction, as well as the need for high levels of protection. Future research can be unequivocally focused on the structural and technological advancement of polymer composites, specifically through optimization aimed at reducing waste and lowering production costs. Full article

Biodegradable hydroretentive polymers, such as UPDT^®, have emerged as promising alternatives to synthetic hydrogels, particularly in pasture systems where sustainable water management is crucial. These materials enhance subsurface drip irrigation by maintaining soil moisture, which supports germination and early root development until roots access deeper water reserves. However, their degradation dynamics in tropical forage systems remain poorly characterized, posing a challenge to long-term application strategies. This study aimed to evaluate the effects of different UPDT^® doses (0, 7.5, 15, 22.5, and 30 kg ha⁻¹) on the morphological and agronomic traits of Mombaça grass under controlled conditions. After a uniformity cycle, treatments were evaluated across four cultivation cycles with monitored irrigation to avoid water deficits. Morphogenetic traits such as number of live leaves (NLL), final number of emerging leaves (NEmL), leaf appearance rate (LAR), and stem elongation rate (SER), as well as shoot dry mass (SDM), were analyzed. Results showed that morphological variables responded quadratically to polymer doses during the initial and intermediate cycles. In the final cycle, reductions in these traits and in water productivity suggested the onset of polymer degradation and loss of hydroretentive capacity. Agronomic traits were influenced throughout all cycles, with the fourth cycle showing the highest SDM due to elevated temperatures. These findings highlight the need to better understand the degradation kinetics of biodegradable hydrogels such as UPDT^® in tropical pastures. Field trials are recommended to define optimal reapplication intervals and integrate degradation monitoring into irrigation planning, ensuring long-term sustainability in pasture management. Full article

Natural fiber-reinforced polymers are gaining popularity as sustainable structural materials. However, their inherent variability can limit their reliability in load-bearing applications. To address this issue, we investigate a novel structural health monitoring method that leverages mechanoelectrical effects in flax fiber-reinforced epoxy composites. In our study, a contactless capacitive coupled measurement setup records electrical polarization during fatigue testing at four load levels. The polarization signals we observed increased with increasing load levels. Additionally, changes in polarization correlate with changes in dynamic modulus, providing early indicators of potential failure. This work lays the foundation for a new type of structural health monitoring in natural fiber-reinforced polymers. Full article