Search Results (6,116)

Polymer/Silica aerogel (SA) composites improve mechanical properties strategically, but the mixing process disrupts the aerogel’s structure, reducing its efficiency due to polymer chains filling the pores. Pre-vulcanized natural rubber latex (PVNRL) with a higher crosslink density can strain the moving chains, thereby preserving the SA-porous structure in the bulk composite for thermal insulation materials. This study aimed to investigate the effects of PVNRL pre-vulcanization time and SA-immersion time in PVNRL. For PVNRL/SA composite preparation, various PVNRL, from 0 days to 8 days of pre-vulcanization time, were mixed with a fixed SA content of 20 parts per hundred of rubber (phr) using a latex compounding method. Subsequently, the PVNRL/SA slurries were cast on glass plates with 0, 3, and 6 days to obtain the PVNRL/SA composite. Considering the effect of pre-vulcanization time, the crosslink density of the composite increased and revealed a peak at PVNRL/SA with 8-day PVNRL by 7.277 ± 0.881 μmol , corresponding to the closest percentage of pore area in the SA’s structure to the pristine SA, and eventually a 42.41% lower thermal conductivity than the PVNRL/SA with 0-day PVNRL exhibited. In addition, the thermal conductivity increased more slowly over immersion time with the presence of 8-day PVNRL. The proposed correlation states that increasing the pre-vulcanization improves the thermal insulation performance of PVNRL/SA composites, emphasizing the reduction of filled SA’s pore with unvulcanized NR chains. Furthermore, the PVNRL/SA composite with 8-day PVNRL maintains thermal stability at 387.3 °C, and can be flexed at room temperature. These fascinating discoveries may be advantageous for further applications related to thin-film and flexible thermal insulation materials. Full article

One of the latest and innovative areas of research in energy is the development of thermoelectric generators (TEGs). A novel family of soft, sustainable energy harvesters, hydrogel-based renewable flexible thermoelectric generators use linked ionic, electronic, and redox processes to transform heat gradients into electrical energy. According to recent research, a hydrogel-based TEG has ionic Seebeck coefficients (S) of the order 10–40 mV K⁻¹, which are tens to hundreds of times greater than those of electronic polymers. Thermal conductivities are modest (~0.3–0.6 W/m·K), ionic conductivities typically vary from 10⁻³ to 10⁻¹ S cm⁻¹, and water-rich gels are naturally soft with elastic moduli ~10³–10⁶ Pa and elongations > 100–800%. Recent developments in the concepts, properties, working mechanism, and potential applications of hydrogel-based thermoelectric generators are the focus of this review paper. We investigate the basic transport processes, such as ionic thermodiffusion, thermoelectric ion–electron coupling, and redox-mediated potential production, that allow thermoelectric conversion in hydrogels. This review identifies bottlenecks such as poor output power under minor gradients, summarize performance parameters, and assess methods to improve efficiency. Wearable and implanted power sources, low-grade waste heat collection, and environmental monitoring are examples of promising applications. Lastly, we describe the research avenues that must be pursued in order to expedite the transition of hydrogel-based thermoelectric generators from lab tests to useful, sustainable energy sources. Therefore, the review can provide fundamental knowledge on hydrogel-based TEGs along with their working principles. Full article

Synthetic polymers are commonly incorporated into natural polymer nanofibers to enhance their overall performance. In this study, we investigated the effects of different poly(vinyl alcohol) (PVA) concentrations (0%, 2.5%, 5%, 7.5%, and 10% w/v) on the properties of gelatin/zein nanofibers. With increasing PVA concentration, fiber diameter significantly decreased from 976 ± 165 nm to 262 ± 60 nm, followed by a gradual increase to 396 ± 81 nm, indicating that PVA plays a crucial role in fiber diameter regulation. At higher concentrations (7.5% and 10% w/v), PVA became dominant, inducing protein aggregation and porous channel formation, which in turn increased the water vapor permeability of the composites. Rheological and mechanical analyses revealed that at these concentrations, the composites exhibited enhanced flexibility while maintaining network stability, demonstrating strong application potential. Furthermore, PVA incorporation induced a slight increase in the primary decomposition temperature (from 320.77 °C to 328.67 °C), indicating enhanced intermolecular compatibility and restricted segmental mobility within the protein–PVA network. Overall, these results establish a theoretical basis for tailoring fiber architecture and interfacial compatibility in natural–synthetic polymer composites. Further, the structural attributes of the resulting fibrous mats indicate their potential for food processing applications beyond conventional food packaging, including use as filtration media. Full article

Antimicrobial polymers are a potential and viable alternative to antibiotic therapies, whose effectiveness is increasingly compromised by the onset of antimicrobial resistance and antibiotic persistence. Antimicrobial polymers also have potential in the formulation of new drug delivery systems. Difficulties in finding new naturally derived compounds and classes of antimicrobials pose a major threat to public health and have made finding an alternative crucial. The aim of this review is to provide a comprehensive overview of the antimicrobial polymers currently available, whether of natural or synthetic origin, and to explore their use in pharmaceutical formulations, including a brief description of their preparation methods. Furthermore, a critical assessment of the advantages, limitations, and potential future developments of these systems will be presented, with particular attention to their clinical applicability, safety profiles, and role in combating antimicrobial resistance. Finally, the review highlights key challenges and future directions for the clinical translation of antimicrobial polymer-based systems, with a focus on safety, scalability, and their potential role in addressing antimicrobial resistance. Full article

Uncontrolled hemorrhage remains a major challenge in trauma care and surgical interventions, where rapid hemostasis and wound sealing are essential for improving patient survival. Natural polymer-based hydrogels have emerged as promising hemostatic materials owing to their excellent biocompatibility, biodegradability, and biomimetic properties. However, their clinical translation remains limited by insufficient mechanical robustness, wet adhesion, and functional responsiveness. To address these challenges, considerable progress has been achieved through rational material design and structural engineering strategies. Representative natural polymers, particularly polysaccharides and proteins, exhibit distinct physicochemical and biological characteristics that determine their hemostatic mechanisms and design strategies. Based on these material platforms, molecular modification strategies, including charge regulation, hydrophobic modification, and bioactive functionalization, have been widely employed to modulate interfacial interactions, platelet adhesion, coagulation activation, and tissue adhesion. In parallel, advanced structural architectures, such as porous, particulate, fibrous, multicrosslinked/multinetwork, and nanocomposite systems, have significantly enhanced fluid absorption, mechanical resilience, stress dissipation, and hemorrhage sealing efficiency. Beyond conventional hemostasis, increasing efforts have focused on integrating multifunctional properties, including antibacterial activity, inflammatory regulation, oxidative stress modulation, tissue regeneration, dynamic monitoring, and stimuli-responsive behaviors. This review systematically summarizes recent advances in natural polymer-based hemostatic hydrogels from the perspectives of advanced material modification strategies, structural engineering approaches, and functional integration, with particular emphasis on the relationships among material characteristics, interfacial behavior, structural organization, and hemostatic performance. Finally, current challenges and future perspectives for clinical translation are discussed, aiming to provide valuable insights for the rational design and clinical implementation of next-generation hemostatic biomaterials. Full article

Developing biodegradable and functional polymeric materials for active food packaging is essential to mitigate the environmental burden of petroleum-based plastics. In this context, gelatin/chitosan (G–Ch) nanofibrous mats were fabricated via solution blow spinning (SBS) and functionalized with snail slime (SS) and Pinus sylvestris essential oil (PSEO) to enhance their bioactivity and barrier performance. SS is rich in glycoproteins and natural bioactive compounds, while PSEO is characterized by terpene-based antimicrobial and antioxidant activities. SS and PSEO were incorporated into the G–Ch polymeric matrix to enhance the bioactivity, structural functionality and preservation performance of the nanofibrous mats. Three formulations (G–Ch, G–Ch–SS, and G–Ch–SS–10PSEO) were designed to elucidate the influence of snail slime and essential oil incorporation on the structure–property–function relationships of the nanofibrous mats. Morphological analysis revealed a smooth and bead-free fibrous structure across all formulations. The average fiber diameter (AFD) increased from 191.83 nm for G–Ch to 263.88 nm for G–Ch–SS and 295.83 nm for G–Ch–SS–10PSEO. FTIR and XRD analyses showed the physical encapsulation of the active compounds without significant chemical interactions. Furthermore, the incorporation of PSEO increased surface hydrophobicity and reduced air permeability, indicating the formation of a more compact fibrous structure with enhanced barrier properties. The functional performance of the nanofibrous mats was significantly improved by the addition of snail slime and PSEO. The G–Ch–SS–10PSEO formulation exhibited the highest antioxidant activity, reaching 36.8% for DPPH and 42.7% for ABTS, along with enhanced antibacterial efficacy against both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Application tests on chicken wings demonstrated that the bioactive nanofibers effectively suppressed microbial growth, limited pH increases, and reduced lipid oxidation during 14 days of refrigerated storage. Overall, the results demonstrate that the synergistic integration of snail slime and essential oil within a biodegradable polymer matrix provides a promising strategy for designing active nanofibrous materials with enhanced structural and bioactive properties for sustainable food-packaging applications. Full article

This study examines the effect of small ply angle deviations on the structural response of carbon fiber-reinforced polymer laminates representative of structures used in unmanned aerial vehicles (UAVs). A combined experimental and numerical approach was applied, including cantilever bending tests and experimental modal analysis, supported by finite element simulations. Laminates with nominal ply orientations of 0°, 5°, and 10° were manufactured using a manual hand lay-up process to reflect typical production variability. The results show that the numerical model accurately captures the observed trends in both bending deformation and natural frequencies, with discrepancies up to 12.5%. A consistent tendency to slightly overestimate stiffness was observed, leading to lower predicted deflections and higher natural frequencies compared to experimental data. The findings confirm that finite element modeling can reliably detect and predict the structural effects of small fiber misalignment, supporting its use in the assessment and design of lightweight composite structures used in UAV applications. Full article

Bioactive peptides (BPs) are widely distributed and exhibit remarkable physiological activities. However, their natural forms are frequently characterized by short half-lives, low membrane permeability, poor stability, and inadequate oral bioavailability, which severely limit their applications in the food, pharmaceutical, and biomaterial fields. Therefore, modification and engineering of natural BPs are essential to surmount these inherent limitations. Synthetic biology-based modification strategies, including amino acid substitution, sequence truncation and hybridization, side-chain functionalization, and main-chain/side-chain integration, are comprehensively summarized in this review. Chemical modification strategies, such as terminal modification, cyclization, backbone modification, polymer conjugation, lipidation, and glycosylation, are also discussed, with particular attention to their advantages, potential drawbacks, and practical limitations. Based on 122 studies identified through systematic literature searches across major scientific databases, this review also discusses the current challenges and future trends in BP modification, providing theoretical guidance and innovative insights for the further development and enhanced utilization of BPs. Full article

In this study, novel electrospun polymer mats based on biocompatible poly(lactic acid) (PLA) and hydrophilic poly(ethylene glycol) (PEG) were successfully fabricated for the co-delivery of two natural polyphenols, quercetin (QUE) and rosmarinic acid (RA). Scanning electron microscopy (SEM) revealed the formation of defect-free, continuous nanofibers with high interconnected porosity. By mimicking the structural features of the native extracellular matrix, these nanofibrous platforms facilitate pronounced combined antioxidant and anticancer action. X-ray diffraction (XRD) analysis confirmed that the rapid solvent evaporation during electrospinning induced a physical state transformation, converting both QUE and RA from their native crystalline structures into an amorphous dispersion within the polymer fibrous materials, thereby optimizing their potential bioavailability. The obtained hybrid fibrous materials possessed good mechanical properties. Moreover, the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay demonstrated that the incorporation of PEG enhanced matrix hydrophilicity, allowing the four-component PLA/PEG/QUE/RA mats to achieve the highest antioxidant efficiency (98.1%), suggesting an enhanced, complementary radical-neutralization pathway. Furthermore, in vitro biological assessments against human cervical carcinoma cell line (HeLa) and normal murine embryo fibroblasts BALB/3T3 demonstrated prominent anticancer activity, while noncancerous cells were significantly less affected. The dual-loaded PLA/PEG/QUE/RA fibrous mats induced significant cell shrinkage, chromatin condensation, and apoptotic cell death in HeLa cells, while normal BALB/3T3 fibroblasts retained cell membrane integrity and displayed higher resistance. Modeled after the native extracellular matrix, these bioinspired materials demonstrate significant antioxidant and anticancer activity, highlighting their potential for applications in localized cancer therapy, wound management, and tissue engineering. Full article

Chinese lacquerware is valued for its distinctive gloss, hardness, and durability. In this study, three layers of natural lacquer were applied to 3D-printed PLA substrates and exposed to UVA-340 accelerated aging for 25 days. The lacquer film gradually became lighter in color, with the lightness value increasing from 30.69 to 44.69. At the same time, gloss decreased from 59.37 to 48.28 GU, while surface roughness increased significantly, with Ra rising from 2.11 to 10.07 μm. Pencil hardness declined from H to 5B, indicating a reduction in surface strength. FTIR results showed partial oxidation of phenolic hydroxyl groups, whereas the aromatic backbone and aliphatic side chains remained largely unchanged. These results suggest that UV aging mainly causes surface photo-oxidation, leading to fading, gloss loss, roughening, and reduced durability of the lacquer coating. SEM images showed that the lacquer surface changed gradually during UV exposure. In the first few days of aging, small cracks started to appear on the surface, along with a bit of powdering. As UV exposure continued, the cracks gradually became larger and began to spread. By the final stage, many of them linked up into a network, but the overall damage slowed down compared to earlier stages. Overall, the process moved through a quick initial change, then a period of crack growth, and finally a more stable phase. These results help make it clearer how UV light affects lacquer coatings on polymer-based materials. Full article

Sulforaphane (SFN), a bioactive compound sourced from cruciferous vegetables, offers significant antioxidant and anti-inflammatory benefits yet its stability in animal feed is a challenge. Nanotechnology-based encapsulation, specifically ionic gelation, has demonstrated efficacy in improving the stability and bioavailability of SFN. This review examines the application of natural polymers such as chitosan and alginate in ionic gelation for the encapsulation of SFN. It also discusses how these polymers can prevent SFN from degrading while traversing the digestive tract. Encapsulation strategies for SFN have been associated with improved bioavailability, with absorption reported in experimental modules, to modulate immune-related and oxidative-stress pathways. However, challenges persist in identifying optimal methods for encapsulating various species, including enhancing encapsulation effectiveness, particle size, and controlled release mechanisms. Additionally, regulatory concerns regarding the safety and environmental impacts of nanoparticles in feed must be addressed. Future research should focus on improving encapsulation techniques and ensuring the safe application of SFN-loaded nanocarriers in livestock feed. Full article

Cellulose nanofibers (CNFs) have significant potential in composites as additives to improve mechanical properties, melt rheology, and more. However, agglomeration of CNFs is a key challenge in composite melt processing as obtaining nano-level dispersion of CNFs often requires cost- and energy-intensive processes (e.g., solvent exchange or freeze drying) due to the strong hornification tendencies of CNF. Herein, we avoid these challenges by using a natural fiber carrier method to integrate CNF into thermoplastic composites. Fibers are co-dried to create a hybrid fiber feedstock for compounding in which natural fibers are decorated with dispersed nanofibers. The hybridized fibers result in up to a 24% increase in tensile strength and up to a 35% increase in Young’s modulus compared to composites only containing natural fibers. The lignocellulosic nanofibers are found to outperform their purely cellulosic counterpart, which is theorized to be due to either an increased propensity for fibrillation of the lignocellulosic fibers or the increased hydrophobicity of the fibers due to the presence of lignin. Surface analysis of fiber feedstocks, via streaming potential measurements and dynamic light scattering (DLS), confirmed a significant change in the feedstock hydrophobicity before and after hybridization. While mild additions of CNF (1 wt.% on the macroscale fiber) do not impact the composite melt viscosity, the viscosity is found to increase at higher CNF loadings (5 wt.% on the macroscale fiber), indicating its utility as a rheology modifier. Lastly, use of these materials as novel feedstocks for medium-scale additive manufacturing in high-fidelity part production was demonstrated. Full article

This study examines the influence of the chemical nature and molecular structure of external electron-donor compounds on the slurry synthesis of isotactic polypropylene in a hydrocarbon diluent using a titanium–magnesium Ziegler–Natta catalyst. Propylene polymerization was carried out at constant temperature, pressure, hydrogen concentration, and fixed molar ratios of the catalyst system components. Alkoxysilanes with different structures were used as external donors: dicyclopentyldimethoxysilane, cyclohexylmethyldimethoxysilane, diisobutyldimethoxysilane, and diethylaminotriethoxysilane; di-n-butyl phthalate was used as a reference compound. It was shown that external donors decrease catalytic activity relative to the donor-free system but increase stereospecificity, as indicated by a lower xylene-soluble fraction and a higher isotactic index of polypropylene. Dicyclopentyldimethoxysilane demonstrated the strongest stereoregulating effect, providing the lowest content of xylene-soluble polymer. The donor structure significantly affected the molecular weight, rheological, and thermal characteristics of polypropylene, including melt flow rate, viscosity-average molecular weight, melting temperature, melting enthalpy, and crystallinity. Comparison with literature data for catalyst systems differing in internal and external donors, as well as in synthesis conditions, showed that catalyst activity and the stereospecificity of the catalyst system may be determined not only by process parameters but also by the electron-donor environment of the active sites. The results support established concepts of external-donor action in Ziegler–Natta catalysis and provide a comparative assessment of alkoxysilane donors and di-n-butyl phthalate under slurry polymerization conditions. Full article

Platinum and palladium nanoparticles (Pt- and Pd-NPs) were synthesized using a green reduction approach with ascorbic acid (AA) or saponin from Quillaja bark (Qb) as reducing agents and stabilized with conventional polymers (PVP, polyvinylpyrrolidone, PEG, polyethylene glycol) or natural surfactants (CG (coco glucoside), Qb). The influence of stabilizer type on reduction efficiency, particle size, and colloidal homogeneity was investigated. Pt-NPs exhibited consistently high reduction efficiencies (>87%) in all systems, whereas Pd-NPs showed lower efficiencies and greater sensitivity to synthesis conditions. AFM and DLS analyses confirmed the formation of particles within the nanometric range. In AA-based systems, Pt-NPs were generally smaller than Pd-NPs, while the opposite trend was observed in Qb-based systems. Natural surfactants provided effective NP stabilization, low values of polydispersity index (PdI), good size control, and stable nanostructures. The results demonstrated that biosurfactant-based stabilizers, particularly CG and Qb, can successfully replace synthetic polymeric stabilizers in the green synthesis of noble metal NPs, supporting the development of more sustainable and environmentally friendly synthesis approaches. Full article

Viscosity reducers are essential additives for water-based drilling fluids (WBDFs), serving to counteract the rheological degradation induced by the high-temperature and high-salinity conditions commonly encountered in deep and ultra-deep well drilling. This paper systematically reviews the research progress in this field, categorizing viscosity reducers into three major systems: modified natural materials, industrial waste utilization, and synthetic polymers. Modified natural material viscosity reducers, derived from renewable materials such as lignin and humic acid via chemical modification, are environmentally friendly products. The preparation of viscosity reducers from industrial wastes realizes both resource recycling and economic benefits. Synthetic polymer viscosity reducers, incorporated with functional monomers such as sulfonic and carboxylic groups, achieve high performance with temperature resistance exceeding 220 °C as well as excellent salt and calcium tolerance via rational molecular design, and represent the current mainstream research direction in the field. This paper provides an in-depth analysis of the action mechanisms of various viscosity reducers, summarizes the performance characteristics, synthesis methods and application status, and identifies challenges in structure–property relationship elucidation, extreme working condition adaptability, and technology transfer efficiency. Finally, future development trends are discussed, with emphasis on precision molecular design, ultimate performance requirements for ultra-deep wells, environmentally sustainable approaches, and the establishment of standardized evaluation protocols. This review aims to provide both theoretical insights and practical guidance to support the efficient development of deep oil and gas resources. Full article