Search Results (1,340)

Growing concern over the environmental impact of conventional plastics has driven the development of biodegradable alternatives. In this context, natural polymers such as starch have emerged as sustainable options. Commercial montmorillonite, implemented as a reference nanomaterial, allows for the enhancement of the properties of biodegradable materials. In this study, commercial cassava starch powder plasticized with water and 35% glycerol, along with commercial nanoclay at concentrations of 0%, 2%, and 4%, was used as film reinforcement. The manufacturing process employed extrusion to evaluate the effectiveness of the nanomaterial in improving the mechanical and functional characteristics of the films. Films with varying concentrations of glycerol and nanoclay were produced to determine the optimal formulation by assessing their rheological, thermal, and mechanical properties. These films were subjected to comprehensive analysis using internationally standardised techniques, including Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), and morphological characterisation via Scanning Electron Microscopy (SEM). Among the properties evaluated, water vapour permeability (WVTR) was of particular interest. Results showed that higher nanoclay content improved moisture retention, thus enhancing the films’ water barrier properties. Mechanical testing indicated that the film with the highest nanoclay concentration, F-g35-NC4, displayed tensile strength values of 0.23 ± 0.02 MPa and elongation of 66.90% ± 4.85, whereas F-g35-NC0 and F-g35-NC2 exhibited lower values. Conversely, the highest tear resistance was also recorded for F-g35-NC4, reaching 0.740 ± 0.009 kg. Contact angle measurements revealed a hydrophilic tendency, with values of 89.93° ± 8.78°. Finally, WVTR analysis confirmed that increased nanoclay content enhanced moisture retention and improved the water barrier performance, with a value of 0.030 ± 0.011 g/m²·day, supporting potential applications in the packaging sector. Full article

Traditional firefighting protective clothing materials, such as meta- and para-aramid fibers, provide significant thermal protection but often fail to adequately manage heat stress and moisture, especially due to the incorporation of semi-permeable membranes within the three-layer garment structure known as turnout gear. Integrating hydrogels into textiles for firefighting personal protective clothing (PPC) could enhance thermoregulation and moisture management, providing firefighters with improved comfort and safety. Hydrogels are three-dimensional, hydrophilic polymer networks capable of holding substantial amounts of water. Their high water content and excellent thermal properties make them ideal for cooling applications. Therefore, this review focuses on the potential of hydrogel-infused textiles to improve firefighters’ PPC by enhancing thermal comfort and moisture management. Specifically, hydrogel structures and engineered properties for enhanced performance are presented, including smart hydrogels and hydration customization mechanisms. Hydrogel integration into firefighting PPC for moisture management and improved thermoregulation is explored, including current and future market projections and state-of-the-art clinical trial findings. Overall, the future of hydrogel-integrated textiles for firefighting PPC is bright, with numerous advancements and trends poised to enhance the safety, comfort, and performance of protective gear. Full article

Inorganic polyphosphate is highly conserved, critical, yet poorly understood polymer that regulates diverse cellular functions in mammals. Its importance is well established in coagulation, inflammation, mitochondrial function, and stress responses, though the molecular mechanisms for these effects remain only partly understood. Fundamental questions also persist regarding its physiological concentration, chain-length distributions, and the mechanisms that regulate its behavior in specific cellular compartments. Progress is limited by the absence of a known mammalian polyphosphate-synthesizing enzyme. Despite this, recent studies have broadened the scope of polyphosphate biology, suggesting roles in protein phase separation, ATP-independent chaperone activity, metabolic regulation, and intracellular signaling. Polyphosphate modulates the mitochondrial permeability transition pore through calcium-dependent regulation and activates factor XII in coagulation. Findings have also introduced potential connections between polyphosphate and processes such as neurodegeneration, cancer, and tissue regeneration. Despite this expanding landscape, many biological effects remain difficult to interpret due to incomplete mapping of protein targets and longstanding technical limitations in detecting and quantifying polyP. This review integrates molecular protein-interaction mechanisms with compartment-specific functions and disease physiology, providing a clearer mechanistic framework while identifying key conceptual and methodological gaps and outlining priorities for advancing polyphosphate research in mammalian systems. Full article

Background: Oral insulin improves compliance and convenience in patients with diabetes who require regular needle injections. However, the clinical application of oral insulin preparations has been limited due to instability and inefficient permeation through the gastrointestinal tract. In this study, a novel cationic polysaccharide nanodrug delivery platform was designed for efficient oral insulin delivery. Methods: The innovative thiolated trimethyl chitosan-grafted β-cyclodextrin (NCT) was synthesized by utilizing N-trimethyl chitosan (TMC) as the polymer backbone. This involved modifying TMC with thiol group-containing N-acetylcysteine and carboxymethyl-β-cyclodextrin that possesses hydrophobic cavities via an amide condensation reaction. Subsequently, this polymer was employed to construct the NCT nanoparticle system using an ionic cross-linking method. The physicochemical properties of the NCT nanoparticles were systematically analyzed, and their therapeutic efficacy was comprehensively evaluated in streptozotocin (STZ)-induced animal models. Results: The NCT nanoparticles demonstrated mucus adhesion, permeability, and pH sensitivity, which facilitated a slow and controlled release within the gastrointestinal microenvironment due to both ionic electrostatic interactions and disulfide bonding interactions. The experiments revealed in vivo that insulin/NCT nanoparticles extended the retention time of insulin in the small intestine. Blood glucose levels decreased to approximately 39% of the initial level at 5 h post-administration while exhibiting smooth hypoglycemic efficacy. Simultaneously, insulin bioavailability increased to 12.58%. Conclusions: The NCT nanoparticles effectively protect insulin from degradation in the gastrointestinal microenvironment while overcoming intestinal barriers, thereby providing a promising approach to oral biomolecule delivery. Full article

Driven by environmental concerns, the packaging industry is shifting toward high-performance and bio-based coating alternatives. In this research, poly(methylmethacrylate) (PMMA) and modified cellulose nanocrystal (m-CNC) were employed as reinforcing agents to develop sustainable poly (lactic acid)-based coatings for packaging applications. Various formulations, influenced by polymer matrix blends and m-CNC loadings (1–5%), were prepared using solvent and applied as protective coating on cardboard paper substrates. The grammage of polymeric coatings (CG) on paper was also investigated using various wet film thicknesses (i.e., 150–250 μm). Accordingly, key parameters including water contact angle, thermal behavior, mechanical performances and barrier properties were systematically evaluated to assess the effectiveness of the developed nanocomposite coatings. As a result, nonylphenol ethoxylate surfactant-modified cellulose nanocrystals exhibited good dispersion and stable suspension in chloroform for one hour, improving compatibility and interaction of polymer–CNC fillers. The water vapor permeability (WVP) of PLA-coated papers was significantly reduced by blending PMMA and increasing the content of m-CNC nanofillers. Furthermore, CNC incorporation enhanced the oil resistance of PLA/PMMA-coated cardboard. Pronounced improvements in barrier properties were observed for paper substrates coated with dry coat weight or CG of ~20 g/m² (corresponding to 250 μm wet film thickness). Coatings based on blended polymer—particularly those reinforced with nanofillers—markedly enhanced the hydrophobicity of the cardboard papers. SEM-microscopy confirmed the structural integrity and morphology of the nanocomposite coatings. Regarding mechanical properties, the upgraded nanocomposite copolymer (PLA-75%/PMMA-25%/m-CNC3%) exhibited the highest bending test and tensile strength, achieved on coated papers and free-standing polymeric films, respectively. Based on DSC analysis, the thermal characteristics of the PLA matrix were influenced to some extent by the presence of PMMA and m-CNC. Overall, PLA/PMMA blends with an optimal amount of CNC nanofillers offer promising sustainable coatings for the packaging applications. Full article

To address the problem of serious gas channeling during CO₂ flooding in low-permeability reservoirs, which leads to poor oil recovery, this study developed a CO₂-resistant gel using a novel CO₂-responsive polymer (ADA) for gas channel control. The ADA polymer was synthesized via free-radical copolymerization of acrylamide (AM), dimethylaminopropyl methacrylamide (DMAPMA), and 2-acrylamido-2-methylpropanesulfonic acid (AMPS), which introduced protonatable tertiary-amine groups and sulfonate moieties into the polymer backbone. Comprehensive characterizations confirmed the designed structure and adequate thermal stability of the ADA polymer. Rheological tests demonstrated that the ADA polymer solution exhibits significant CO₂-triggered viscosity enhancement and excellent shear resistance. When crosslinked with phenolic resin, the resulting ADA gel showed outstanding CO₂ tolerance under simulated reservoir conditions (110 °C, 10 MPa). After 600 s of CO₂ exposure, the ADA gel retained over 99% of its initial viscosity, whereas a conventional HPAM-based industrial gel degraded to 61% of its original viscosity. The CO₂-resistance mechanism involves protonation of tertiary amines to form quaternary ammonium salts, which electrostatically interact with sulfonate groups, creating a reinforced dual-crosslinked network that effectively protects the gel from H⁺ ion attack. Core flooding experiments confirmed its ability to enhance oil recovery by plugging high-permeability channels and diverting flow, achieving a final recovery of up to 48.5% in heterogeneous cores. This work provides a novel gel system for improving sweep efficiency and storage security during CO₂ flooding in low-permeability reservoirs. Full article

Studying surface energy and permeability offers insights into the relationship between temporary polymers and the oral environment. Variations in contact angle and surface free energy may signify modifications in surface polarity and tendency for plaque buildup, staining, or microcrack formation. Objectives: The present study aims to evaluate the influence of simulated salivary and chemical aging conditions on the surface and mechanical properties of 3D-printed PMMA provisional materials. Methods: Two 3D-printed polymethyl methacrylate (PMMA) resins were investigated, namely Anycubic White (Anycubic, Shenzhen, China) and NextDent Creo (NextDent, 3D Systems, Soesterberg, The Netherlands), using two aging protocols. Protocol A consisted of chemical aging in an alcohol-based mouthwash, while Protocol B involved thermal aging in artificial saliva. After aging, surface properties (wettability and SFE) and compressive behaviour were analyzed. Statistical analysis was conducted to assess the influence of temperature, immersion duration, and aging medium, with significance established at p < 0.05. Results: In Protocol A, mechanical properties showed a time-dependent decrease, with material-specific stabilization trends. In Protocol B, thermal aging resulted in elastic modulus reductions ranging from 35% to 46% relative to the reference. The yield strength exhibited similar tendencies. In Protocol A, X samples exhibited a consistent decline, while C samples stabilized after 14 days. For Protocol B, the fitted model produced residuals under 2%, confirming temperature as the primary variable. Conclusions: Chemical and thermal aging influence the physical and mechanical properties of the analyzed 3D-printed PMMA. Among the two protocols, thermal aging in artificial saliva resulted in more pronounced material degradation. After chemical aging in mouthwash, the surface free energy remained almost constant. After thermal aging, all samples demonstrated a gradual rise in SFE with prolonged immersion duration. The current study offers valuable insights into the environmental stability of printed PMMA; however, it is an in vitro evaluation. The findings indicate that temperature exposure and prolonged contact with oral hygiene products may affect the mechanical reliability of 3D-printed provisional restorations, which must be considered during material selection for longer temporary usage. Additionally, spectroscopic and microscopic analyses might better clarify the molecular-level chemical alterations linked to aging. Full article

Class III reservoirs in the Daqing Oilfield are characterized by low permeability and strong heterogeneity, posing significant challenges to enhanced oil recovery (EOR). To improve the recovery efficiency of these reservoirs, the viscosifying ability, stability, shear resistance, and profile-control performance of fifteen polymer solutions were experimentally evaluated, and the two most compatible formulations were selected for the Daqing Class III reservoirs. Subsequently, a three-dimensional physical model equipped with real-time saturation monitoring was employed to compare the EOR performance of the selected polymers. The results indicate that a 1500 mg L⁻¹ polymer solution with a molecular weight (Mw) of 16 × 10⁶ Da and a 1200 mg L⁻¹ polymer solution with an Mw of 19 × 10⁶ Da exhibit the best compatibility with the target formation. After injecting the 1500 mg L⁻¹ (Mw = 16 × 10⁶ Da) polymer solution, the ultimate recovery reached 53.38%, with displacement efficiencies of 64.34% and 58.16% and sweep efficiencies of 92.26% and 80.35% in the high- and low-permeability layers, respectively. Injection of the 1200 mg L⁻¹ (Mw = 19 × 10⁶ Da) polymer solution yielded an overall recovery of 47.71%, corresponding to displacement efficiencies of 60.34% and 54.16% and sweep efficiencies of 88.52% and 76.38%. Consequently, the 1500 mg L⁻¹ (Mw = 16 × 10⁶ Da) polymer solution delivers the highest recovery increment in Class III reservoirs. These findings provide valuable guidance for the efficient polymer-flooding development of Class III reservoirs in Daqing and analogous formations worldwide. Full article

Tröger’s base (TB) polymers have received increasing attention as a novel class of polymers with intrinsic microporosity, particularly for applications in gas separation. In this study, TB was quaternized with hydrophobic long chains to create a microphase-separated structure to enhance gas separation performance. On one hand, the tertiary amine structure of TB enabled facile grafting modification through the Menshutkin reaction. On the other hand, microphase-separated channels were created in the quaternized Tröger’s base (QTB) membrane due to the polarity differences between the hydrophilicity of the quaternary ammonium groups and hydrophobicity of iodoalkanes, providing channels for gas transport within the membrane and thereby improving permeability selectivity. The successful synthesis of QTB membranes was confirmed by FTIR and ¹H NMR spectroscopy, while AFM and SAXS analyses validated the microphase-separated morphology. To investigate the impact of microphase separation on oxygen permeability and selectivity, different iodoalkanes and various concentrations of iodobutane were grafted onto the TB backbone. Among the prepared membranes, QTB-C₄-70% membrane exhibited the highest in O₂ permeability. Gas separation performance under different O₂ pressures and temperatures revealed that O₂ permeability decreased slightly with increasing pressure, indicating good pressure stability of the membrane. With increasing temperature, the permeability increased while the selectivity decreased. These findings demonstrated that microphase-separated QTB membranes offer a viable strategy for creating effective materials for gas separation. Full article

The study presents a sustainable approach to valorizing hazelnut processing by-products, specifically skins and shells, through their conversion into bioactive polyphenol-rich extracts using pressurized hot water extraction (PHWE), an environmentally friendly green technology. PHWE yielded extracts with total phenolic contents of 25.4 mg GAE/g dw (shell) and 83.7 mg GAE/g dw (skin), which were incorporated into biodegradable poly(vinyl alcohol)/carboxymethyl cellulose (PVA/CMC) films at concentrations of 1–3% (w/v). The resulting composites were comprehensively characterized in terms of structural, mechanical, thermal, and barrier properties. FTIR, DSC, and XRD analyses demonstrated strong hydrogen bonding, increased thermal stability, and reduced crystallinity due to polyphenol–polymer interactions. Phenolic incorporation enhanced UV-blocking capability, increased antioxidant activity by up to five-fold, and reduced oxygen permeability from 0.048 to 0.015 (cm³·mm·m⁻²·day⁻¹·atm⁻¹) (69% reduction, p < 0.05), compared to neat PVA while maintaining desirable transparency (>70%). Optimal formulations (HSkE-II) exhibited a 39% increase in elongation at break and improved flexibility without compromising film integrity. Application tests using fresh-cut apples, watermelon, and chicken revealed significant reductions in microbial growth (up to ~1.2 log CFU/g), lipid oxidation, and weight loss during storage, confirming the films’ potential for active food packaging. This work highlights an efficient valorization strategy for nut industry by-products and demonstrates their functional integration into sustainable biodegradable packaging systems. Full article

To meet the demanding requirements of high permeability and early strength in seepage control grouting for water-sealed underground caverns, a series of cement-based grouts was developed via novel polymer modification techniques. A systematic orthogonal experiment was designed to evaluate the influence of five key factors—W/C, CWRA, PS, TEA, and AS—on the workability and mechanical properties of the grouts. Range, variance, and comprehensive analyses were conducted to determine the weight of each factor. Based on these findings, quantitative methods were employed to optimize mix proportions for two specific engineering purposes: sealing permeable fractures and plugging grouting holes. The optimized mixes exhibited enhanced workability and mechanical performance, thereby offering a reliable technical solution for seepage control in water-sealed underground caverns. Full article

This work reports on the synthesis and ring-opening metathesis polymerization (ROMP) of two novel homologous sulfonyl-containing norbornene dicarboximide monomers, specifically, N-4-(trifluoromethylsulfonyl)phenyl-norbornene-5,6-dicarboximide (1a) and N-4-(trifluoromethylsulfonyl)phenyl-7-oxanorbornene-5,6-dicarboximide (1b) using the Grubbs 2nd generation catalyst (I). The polymers are thoroughly characterized by nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FT-IR), thermomechanical analysis (TMA), thermogravimetric analysis (TGA), atomic force microscopy (AFM), and X-ray diffraction (XRD), among other techniques. A comparative study of gas transport in membranes based on these ROMP-prepared polymers is performed and the gases studied are hydrogen, oxygen, nitrogen, carbon dioxide, methane, ethylene and propylene. It is found that the presence of sulfonyl pendant groups in the polymer backbone increases the gas permselectivity in slight detriment of the gas permeability compared to a polynorbornene dicarboximide lacking sulfonyl groups. The membrane of the sulfonyl-containing polymer with an oxygen heteroatom in the cyclopentane ring, 2b, is also found to have one of the largest permselectivity coefficients reported to date for the separation of H₂/C₃H₆ in glassy polynorbornene dicarboximides. Full article

Contaminated water detoxification remains difficult due to the presence of persistent halo-organic contaminants, such as perfluorooctanoic acid (PFOA) and chlorophenols, which are chemically stable and resist conventional purification methods. Functionalized membrane-based separation and decontamination have garnered immense attention in recent years. Commercially available microfiltration membrane (PVDF) and polymeric non-woven fiber filters (glass and composite) are functionalized with poly(methacrylic acid) (PMAA) that shows outstanding pH-responsive performance and tunable water permeability under ambient conditions perfect for environmental applications. Polymer loading based on weight gain measurements on PMAA–microglass composite fibers (137%) and microglass fibers (116%) confirmed their extent of functionalization, which was significantly greater than that of PVDF (25%) due to its widely effective pore diameter. Presence of chemically active hydrogel within PVDF matrix was validated by FTIR (hydroxyl/carbonyl) stretch peak, substantial decrease in contact angle (68.8° ± 0.5° to 30.8° ± 1.9°), and decrease in pure water flux from 509 to 148 LMH/bar. Nanoparticles are generated both in solution and within PVDF using simple redox reactions. This strategy is extended to PVDF-PMAA membranes, which are loaded with Fe/Pd nanoparticles for catalytic conversion of 4-chlorophenol and PFOA, forming Fe/Pd-PVDF-PMAA systems. A total of 0.25 mg/L Fe/Pd nanoparticles synthesized in solution displayed alloy-type structures and demonstrated a strong catalytic performance, achieving complete hydrogenation of 4-chlorophenol to phenol and 67% hydrogenation of PFOA to its reduced form at 22–23 °C with ultrapure hydrogen gas supply at pH 5.7. These results underscore the potential of hybrid polymer–nanoparticle systems as a novel remediation strategy, integrating tunable separation with catalytic degradation to overcome the limitations of conventional water treatment methods. Full article

Low-melting bioabsorbable polymers, such as poly(caprolactone-co-lactide) (PCLA), hold significant promise for biomedical applications. However, achieving high-precision micro- and nanotopographical functionalization remains a formidable challenge due to the material’s susceptibility to thermal deformation during conventional thermal molding processes. In this study, functional microstructured PCLA coatings were engineered via low-temperature nanoimprint lithography utilizing a TiO₂–SiO₂ gas-permeable mold. These molds were synthesized via a sol–gel method utilizing titanium dioxide and silicon precursors. The gas-permeable nature of the mold facilitated the efficient evacuation of trapped air and volatiles during the imprinting process, enabling the high-fidelity replication of microstructures (1.3 μm height, 3 μm pitch) and nanostructured PCLA coatings featuring linewidths as narrow as 600 nm. The resultant microstructured PCLA coatings demonstrated modulated surface wettability, evidenced by an increase in water contact angles from 70.1° to 91.4°, and exhibited enhanced FD4 elution kinetics. These results confirm morphology-driven functionalities, specifically hydrophobicity and controlled release capabilities. Collectively, these findings underscore the efficacy of this microfabrication approach for polycaprolactone-based materials and highlight its potential to catalyze the development of high-value-added biomaterials for advanced medical and life science applications. This study establishes a foundational framework for the practical deployment of next-generation bioabsorbable materials and is anticipated to drive innovation in precision medical manufacturing. Full article

Polymer solutions exhibit radial flow characteristics upon injection into a formation via the wellbore. Accurately characterizing their viscoelastic properties at varying seepage velocities and quantifying their impact on displacement efficiency are crucial for advancing polymer flooding technology. This study simulated shear rate variations during polymer injection and integrated laboratory-measured viscoelastic properties with permeability characteristics in porous media. An analysis of the oil displacement performance between viscoelastic polymer solutions and a purely viscous fluid, glycerol, was conducted. The key findings are as follows: (1) Polymer elasticity, characterized by the first normal stress difference, diminishes with decreasing injection time/solution concentration. Significant viscoelasticity is observed near the wellbore, weakening in deeper reservoir regions. (2) The polymer type and injection conditions govern the development of solution “effective viscosity” during porous medium flow. A fundamental trend under elevated flow velocities is an increase in effective viscosity with shear rate. (3) Comparison with glycerol demonstrates that the viscoelastic effect of polymer solutions enhances heavy-oil displacement efficiency. The magnitude of this viscoelastic effect within the porous medium directly correlates with its contribution to improved displacement efficiency. Full article