Search Results (9,621)

Pressure-sensitive adhesion arises at a specific rheological behavior of polymer systems, which should correlate with their relaxation properties, making them potentially useful for predicting and altering adhesive performance. This work systematically studied the rheology of eco-friendly pressure-sensitive adhesives based on non-crosslinked polyisobutylene ternary blends free of solvents and byproducts, which serve for reversible adhesive bonding. The ratio between individual polymer components differing in molecular weight affected the rheological, relaxation, and adhesion properties of the constituted adhesive blends, allowing for their tuning. The viscosity and viscoelasticity of the adhesives were studied using rotational rheometry, while their adhesive bonds with steel were examined by probe tack and shear lap tests at different temperatures. The adhesive bond durability at shear and pull-off detachments depended on the adhesive composition, temperature, and contact time under pressure. The double differentiation of the continuous relaxation spectra of the adhesives enabled the accurate determination of their characteristic relaxation times, which controlled the durability of the adhesive bonds. A universal linear correlation between the reduced failure time of adhesive bonds and their reduced formation time enabled the prediction of their durability with high precision (Pearson correlation coefficient = 0.958, p-value < 0.001) over at least a four-order-of-magnitude time range. The reduction in the formation/failure times of adhesive bonds was most accurately achieved using the longest relaxation time of the adhesives, associated with their highest-molecular-weight polyisobutylene component. Thus, the highest-molecular-weight polymer played a dominant role in adhesive performance, determining both the stress relaxation during the formation of adhesive bonds and their durability under applied load. In turn, this finding enables the prediction and improvement of adhesive bond durability by increasing the bond formation time (a durability rise by up to 10–100 times) and extending the adhesive’s longest relaxation time through elevating the molecular weight or proportion of its highest-molecular-weight component (a durability rise by 100–350%). Full article

This study developed a beta-cyclodextrin polymer crosslinked with citric acid (CDCAPol) for removing water contaminants using methylene blue (MB) as a model compound. The polymer, which features free carboxyl groups and cyclodextrin cavities, demonstrated high adsorptive capacity. Under optimal conditions (0.01 g adsorbent, pH 6, and 50 mg/dm³ MB), a removal efficiency of 99.2% was achieved, with a maximum adsorption capacity of 126.58 mg/g as determined by the Langmuir isotherm. Kinetic data fit the best to the pseudo-second-order model, highlighting strong interactions between MB and the polymer. This promising material may find applications in wastewater treatment and environmental protection. Full article

The development of controlled-release fertilizers (CRFs) has faced significant challenges due to high hydrophilicity and short release lifespan of bio-based materials, as well as non-renewable and high cost of polyester polyols (PPs). In this study, lignin-based polyols (LPs) and PPs were modified to form a cross-linked polymer film on the surface of urea through an in situ reaction. This approach effectively balanced the slow-release ability and environmental protection of controlled-release fertilizer films. A two-factor, five-level orthogonal test was designed for the mass ratio of lignin/polyester polyol and polyol/polyaryl polymethylene isocyanate (PAPI), comprising a total of 25 treatments. The results indicated that the appropriateness of lignin polyols increased the hydrogen bond content of polyurethane membrane, improved the mechanical strength of the fertilizer membrane shell, and effectively reduced friction losses during storage and transportation. Moreover, optimizing the polyol-to-PAPI ratio minimized coating porosity, produced a smoother and denser surface, and prolonged the nitrogen release period. When the lignin polyol dosage was 25% and the polyol to PAPI ratio was 1:2, the nitrogen release time of the prepared coated urea extended to 32 days, which was 3.5 times longer than that of lignin polyurethane coated urea (7 days). The incorporation of lignin and the optimal ratio of coating materials significantly improved the controlled-release efficiency of coated fertilizer, providing theoretical support for the sustainable agricultural application of biomass. Full article

Malignant melanoma is a highly metastatic skin cancer, representing about 5% of all cancer diagnoses in the United States. Conventional chemotherapy often has limited effectiveness and severe systemic side effects. This study explores a localized, topical delivery system using cisplatin-loaded nanomembranes as a safer and more targeted alternative. Cell viability assays established the safe cisplatin concentrations for tissue culture. Gelatin-based nanomembranes incorporating cisplatin were fabricated via electrospinning. Biocompatibility and therapeutic efficacy were tested by applying the membranes to cultured melanoma and normal skin cells. Controlled drug release profiles were evaluated by adjusting cross-linking times. Cisplatin concentration between 3.125 and 12.5 µg/mL were found safe. Nanomembranes with these doses effectively eliminated melanoma cells with minimal harm to healthy skin cells. Drug-free membranes showed high biocompatibility. Cross-linking duration allowed tunable and stable drug release. Cisplatin-loaded gelatin nanomembranes offer a promising topical therapy for melanoma, enhancing drug targeting while reducing systemic toxicity. This approach may serve as a cost-effective alternative to systemic treatments like immunotherapy. Future research will focus on in vivo testing and clinical application. Full article

Infectious keratitis (IK), including bacterial, fungal, parasitic, and viral etiologies, continues to represent a significant cause of ocular morbidity in the United States and around the world. Corneal scraping for smears and cultures remains the gold standard in diagnosing IK; however, molecular diagnoses, including metagenomic deep sequencing (MDS), are promising emerging diagnostic tools. Despite recent interest in procedural treatment such as riboflavin photoactivated chromophore corneal collagen cross-linking (PACK-CXL) and Rose Bengal photodynamic antimicrobial therapy (RB-PDAT), medical treatment advances have remained stagnant. Methods: This review highlights IK pathogens obtained from corneal cultures at Bascom Palmer Eye Institute (BPEI) from 2011 to 2021 and provides the current BPEI algorithms for initial management of IK or as a referred clinically worsening patient. The roles of corticosteroid therapy, PACK-CXL, and RB-PDAT for IK are also summarized. Results: A total of 9326 corneal cultures were performed at BPEI between 2011 and 2021, and only 3609 (38.7%) had a positive organism identified, of which bacteria were the most common (83.4%). Fortified vancomycin and tobramycin are recommended as first-line medical therapy for IK patients based on culture sensitivity data for the top Gram-negative (Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus) bacteria. PACK-CXL and RB-PDAT may benefit IK patients with corneal melting and fungal IK, respectively. Conclusions: Drug holidays, minimizing contamination, and optimizing sample order are crucial to maximizing corneal culture positivity. PACK-CXL and RB-PDAT are promising procedural advancements for IK therapy. Full article

Efficient and selective separation of gallium (Ga(III)) from alkaline industrial waste streams remains a significant challenge due to the coexistence of chemically similar ions such as Al(III) and V(V). In this study, a novel ion-imprinted chitosan-based adsorbent (CS/(H-CGCS)-Ga-IIP) was synthesized via a hybrid cross-linking strategy using glutaraldehyde and siloxane-modified chitosan. The optimized material exhibited a high adsorption capacity of 106.31 mg·g⁻¹ for Ga(III) at pH 9, with fast adsorption kinetics reaching equilibrium within 60 min. Adsorption behavior followed the pseudo-second-order kinetic and Langmuir isotherm models, and thermodynamic analysis indicated a spontaneous and endothermic process. In simulated Bayer mother liquor systems, the material demonstrated outstanding selectivity and a distribution coefficient ratio k_d-Ga/k_d-Al = 146.9, highlighting its strong discrimination ability toward Ga(III). Mechanistic insights from SEM-EDS, FTIR, and XPS analyses revealed that Ga(III) adsorption occurs via electrostatic interaction, ligand coordination, and structural stabilization by the siloxane network. The material maintained good adsorption performance over three regeneration cycles, indicating potential for reuse. These findings suggest that CS/(H-CGCS)-Ga-IIP is a promising candidate for the sustainable recovery of gallium from complex alkaline waste streams such as Bayer process residues. Full article

Hydrogels are water-rich polymeric networks mimicking the body’s extracellular matrix, making them highly biocompatible and ideal for precision medicine. Their “tunable” and “smart” properties enable the precise adjustment of mechanical, chemical, and physical characteristics, allowing responses to specific stimuli such as pH or temperature. These versatile materials offer significant advantages over traditional drug delivery by facilitating targeted, localized, and on-demand therapies. Applications range from diagnostics and wound healing to tissue engineering and, notably, cancer therapy, where they deliver anti-cancer agents directly to tumors, minimizing systemic toxicity. Hydrogels’ design involves careful material selection and crosslinking techniques, which dictate properties like swelling, degradation, and porosity—all crucial for their effectiveness. The development of self-healing, tough, and bio-functional hydrogels represents a significant step forward, promising advanced biomaterials that can actively sense, react to, and engage in complex biological processes for a tailored therapeutic approach. Beyond their mechanical resilience and adaptability, these hydrogels open avenues for next-generation therapies, such as dynamic wound dressings that adapt to healing stages, injectable scaffolds that remodel with growing tissue, or smart drug delivery systems that respond to real-time biochemical cues. Full article

Self-healing coatings can replace conventional coatings and are capable of self-healing and continuing to protect the substrate after coating damage. In this study, two types of self-healing resins were synthesized as coatings: Type-A via Diels–Alder crosslinking of furfuryl-modified diglycidyl ether bisphenol A with bismaleimide, and Type-B through epoxy blending/curing to form a semi-interpenetrating network. FTIR and Raman spectroscopy confirmed the formation of Diels–Alder (DA) bonds, while GPC tests indicated incomplete monomer conversion. Both resins were applied to glass and wood substrates, with performance evaluated through TGA, colorimetry (ΔE), gloss analysis, and scratch-healing tests (120 °C/30 min). The results showed that Type-A resins had a higher healing efficiency (about 80% on glass substrates and 60% on wood substrates), while Type-B resins had a lower healing rate (about 65% on glass substrates and 55% on wood substrates). However, Type-B is more heat-resistant, has a slower decomposition rate between 300 and 400 °C, higher gloss retention, and less color difference (ΔE) between wood and glass substrates. The visible light transmission of Type-B (74.14%) is also significantly higher. Full article

Chronic wounds disrupt natural healing and tissue regeneration, posing a major challenge in healthcare. Conventional wound care often lacks effective drug delivery, tissue integration, infection control, and patient comfort. However, injectable hydrogels offer localized, minimally invasive treatment and conform to irregular wound shapes. This study presents carboxymethyl cellulose (CMC)-based injectable hydrogels, prepared via Diels–Alder click chemistry using highly furan functionalized CMC (45%) and a bismaleimide crosslinker. The hydrogels showed a rapid gelation time (<490 s) under physiological conditions. The hydrogel exhibited favorable physicochemical and mechanical properties, as well as sustained curcumin release (∼80% in 5 days). In vitro studies confirmed excellent biocompatibility with NIH3T3 fibroblasts and notable antibacterial activity against E. coli, supporting its potential for wound healing applications. Full article

The advancement of laser-induced graphene (LIG) has significantly enhanced the development of wearable and flexible electronic devices. Due to its exceptional physical, chemical, and electronic properties, LIG has emerged as a highly effective active material for wearable sensors. However, despite the wide range of materials suitable as precursors for LIG, the scarcity of stretchable and biocompatible polymers amenable to laser graphenization has remained a persistent challenge. In this study, laser-induced graphene (LIG) was fabricated directly on biocompatible and flexible cross-linked PDMS/PEG (with M_n (PEG) = 400 g/mol) composites for the first time, enabling their application in wearable sensors. The addition of PEG compensates for the low carbon content in PDMS, enabling efficient laser graphenization. Laser parameters were systematically optimized to achieve high-quality graphene, and a comprehensive characterization with varying PEG content (10–40 wt.%) was conducted using multiple analytical techniques. Tensile tests revealed that incorporating PEG significantly enhanced elongation at break, reaching 237% for PDMS/40 wt.% PEG while reducing Young’s modulus to 0.25 MPa, highlighting the excellent flexibility of the substrate material. Surface analysis using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and Raman spectroscopy demonstrated the formation of high-quality few-layer graphene with the fewest defects in PDMS/40 wt.% PEG composites. Nevertheless, the adhesion of electrical contacts to LIG that was directly induced on PDMS/PEG proved to be challenging. To overcome this challenge, we produced devices by means of laser induction on polyimide and transfer to PDMS/PEG. We demonstrate the practical utility of such devices by applying them to monitor limb motion in real time. The sensor showed a stable and repeatable piezoresistive response under multiple bending cycles. These results provide valuable insights into the fabrication of biocompatible LIG-based flexible sensors, paving the way for their broader implementation in medical and sports technologies. Full article

Wastewater containing heavy metals can come from a variety of sources and is extremely toxic and hard to break down. Conventional treatment methods can easily result in secondary pollution and are expensive. The research on magnetic chitosan composites, a new adsorbent in the treatment of heavy metal wastewater, is methodically reviewed in this paper. It offers a theoretical foundation for the creation of more environmentally friendly and effective wastewater treatment technology by examining its preparation and modification technology, adsorption mechanism, and application performance. This paper provides a summary of the technology used to prepare and modify magnetic chitosan composites. Both the cross-linking and co-precipitation methods are thoroughly examined. A summary of the fundamental process of heavy metal ion adsorption is provided, along with information on the chemical and physical impacts. Of these, chemical adsorption has been shown to work well with the majority of heavy metal adsorption systems. According to application research, magnetic chitosan exhibits good adaptability in real-world industrial wastewater treatment and has outstanding adsorption performance for various heavy metal ion types and multi-metal coexistence systems (including synergistic/competitive effects). Lastly, the optimization of the material preparation and modification process, the mechanism influencing the various coexisting ion types, and the improvement of regeneration ability should be the main areas of future development. Full article

Cellulose nanofibril (CNF)-based hydrogels, owing to their sustainability, biocompatibility, and versatile mechanical properties, are promising for biomedical applications. This review analyzes the recent advances and biomedical applications of CNF hydrogels. CNF hydrogels can be prepared via physical and chemical crosslinking. Physical crosslinking involves surface charge density control, pH manipulation, and flow-based processing to generate stable networks, whereas chemical crosslinking employs agents such as epichlorohydrin and citric acid to form permanent covalent bonds. These approaches enable precise control over hydrogel properties, including mechanical strength, porosity, and stimuli responsiveness. CNF hydrogels are particularly promising in drug delivery systems and tissue engineering. CNFs as drug delivery vehicles offer enhanced bioavailability and drug loading capacity owing to their open pore structure and large surface area. Recent developments in stimuli-responsive and injectable CNF hydrogels have enabled controlled drug release and improved targeting capabilities. Moreover, CNF hydrogels serve as effective scaffolds for cell growth and tissue regeneration, with applications in cartilage engineering and wound healing. Integrating CNF hydrogels with 3D bioprinting technology has generated complex tissue structures. However, several challenges remain, including the need for the standardization of toxicology assessments, optimization of large-scale production processes, and development of sophisticated control mechanisms for drug delivery. Future research should advance manufacturing technologies, improve long-term stability, and develop standardized testing protocols for regulatory compliance. Full article

Hydrogel is a new type of lubricating material, and its lubrication performance is influenced by factors such as water content, chemical structure, cross-linking density, and friction pair materials. Currently, research on the lubrication performance of hydrogels has not formed a unified standard and system. Given that the lubricity of hydrogels mainly depends on their components and structure, as well as the chemical interactions between the polymer chains of the hydrogel network and the friction interface, this review systematically discusses the diverse design strategies of hydrogel lubricants based on the hydration and boundary lubrication mechanisms of gels, while elucidating the underlying enhancement mechanisms, as well as the corresponding tribological behavior and applications for different strategies. Finally, the main challenges and future research directions are underlined, aiming to provide theoretical and technical support for the design optimization and practical application of advanced hydrogel lubrication materials. Full article

Ecological restoration in arid coal-mining regions faces extreme challenges due to soil infertility, salinization, and water scarcity. This study addresses these limitations in the Santanghu Shitoumei No. 1 open-pit mine (Xinjiang), where gypsum gray-brown desert soil, minimal rainfall (199 mm/yr), high evaporation (1716 mm/yr), and persistent gale-force winds exacerbate revegetation efforts. To overcome the high cost, short lifespan, and poor practicality of commercial water-retaining agents, we developed a novel humic acid (HA) and sodium carboxymethyl cellulose (CMC) composite water-absorbing resin (HA-CMC). Optimal synthesis parameters—identified as acrylic acid (AA)–carboxymethyl cellulose (CMC)–humic acid (HA)–Acrylamide (AM)–N,N’-methylene diacrylamide (MBA)–Ammonium persulphate (APS) = 100%:15%:4.5%:25%:0.6%:0.8%—yielded effective crosslinking, confirmed via FTIR and SEM. Performance benchmarking against existing agents demonstrated superior attributes. Field application in the mine’s demonstration area significantly enhanced surface vegetation and soil fertility, confirming the resin’s potential for large-scale soil remediation and ecological restoration in arid mining environments. Full article

The development of stable and efficient heterogeneous Fenton oxidation for organic pollutant degradation is crucial to avoid iron sludge formation and cumbersome filtration processes. In this study, iron oxide/carbon aerogel was prepared via the sol–gel method, freeze-drying, and high-temperature carbonization using iron nitrate heptahydrate, ammonium hydroxide, and cellulose as raw materials, with polyvinylimine serving as the crosslinking agent. To enhance the pH adaptability of the catalyst, copper and cerium elements were introduced. The characterization results demonstrate the iron (III) oxide within the carbon aerogel, achieving phenol degradation efficiency exceeding 95% within 120 min. Meanwhile, the introduction of copper and cerium accelerated the degradation of phenol while maintaining a certain catalytic degradation effect at pH 5-7. In addition, the catalyst exhibited excellent recyclability, retaining 85% of its initial degradation efficiency after five reaction cycles. This work offers a new method for the development of heterogeneous Fenton catalysts. Full article