Search Results (66)

The subject of CO₂ subsurface storage security has never been more critical, and there is a need to explore the injection of functional materials that are capable of providing both conformance control and in situ CO₂ adsorption, thereby improving overall formation storage integrity. Herein, a molecular dynamics simulation method was used to investigate the adsorptive tendency of two variants of interpenetrating network (IPN) composite materials comprising amine-stabilized hydrophobically modified cellulose sulphates and methylene bisacrylamide crosslinked polyacrylamide. Using the COMPASS III force field and Metropolis Monte Carlo, the diffusivity and adsorption isotherms for CO₂ were determined in the IPN gels, respectively. The results indicate that the two interpenetrating networks D-I-AM-MBA-G-Cl and D-II-AM-MBA-G-Cl demonstrated reasonable CO₂ adsorption. In saline conditions, the adsorption was further enhanced with diffusion coefficients of 4.87 × 10⁻⁴ cm²/s and 2 × 10⁻⁶ cm²/s. The adsorption isotherm of D-I-AM-MBA-G-Cl closely fits the Sips equation, with a regression coefficient of 0.9996, while that of D-II-AM-MBA-G-Cl follows the Temkin isotherm with an R² value of 0.9885. This study revealed that carefully designed plugging agents with strong CO₂ adsorption tendencies can aid in the improvement of the geosequestration integrity of subsurface formations. Full article

Guanidinoacetic acid (GAA), an important feed additive, shows poor powder properties due to its morphological characteristics. In this study, GAA was employed as a model compound to investigate the regulatory effects of polymeric additives (hydroxypropyl methyl cellulose, hydroxypropyl cellulose, and polyacrylamide) on its crystal growth and powder properties through integrated experimental and molecular simulation approaches. In situ single-crystal growth experiments reveal that hydroxypropyl methyl cellulose (HPMC) and hydroxypropyl cellulose (HPC) can selectively suppress the growth of the (11–1) crystal face while slightly promoting the growth of the (011) crystal face, thereby altering the relative growth rates and modifying the final crystal morphology. However, polyacrylamide (PAM) inhibits the growth of both the (11–1) and (011) crystal faces, resulting in negligible alteration of GAA crystal morphology. Growth kinetic analysis indicates that crystal growth is governed by a surface integration-controlled mechanism. Molecular dynamics simulations further demonstrate that the additive preferentially adsorbs onto specific crystal faces, reducing interfacial solute accumulation and inhibiting molecular diffusion. Collectively, these findings demonstrate that additives exert synergistic control over crystal morphology and particle size distribution through selective adsorption and modulation of interfacial mass transfer. This research provides mechanistic insights and theoretical guidance for the regulation of crystallization processes via additive intervention. Full article

Modern wound care is challenged by the emergence of antibiotic-resistant bacterial strains, causing the need for advanced dressing materials that provide infection control while promoting healing. Although polyacrylamide (PAAm) hydrogels are widely investigated due to their biocompatibility, their lack of intrinsic antibacterial activity and poor mechanical properties restrict their clinical use. To overcome these limitations, this study proposes a natural–synthetic hydrogel that combines PAAm with TEMPO-oxidized cellulose nanofiber (TOCNF) functionalized silver nanoparticles (AgNPs). The synthesis is performed through the polymerization of the synthetic monomer in the presence of the TOCNF–AgNPs, the nanofibrillar cellulose simultaneously serving as a reducing and stabilizing agent for AgNPs, and as a plasticizer for the PAAm network. Morpho-structural analysis of the hybrid precursor (TOCNF–AgNPs) revealed two populations of AgNPs, offering a cumulative effect between rapid bacterial penetration and a prolonged ionic reservoir, while maintaining the stability of the system. The subsequent incorporation of the hybrid into PAAm matrix resulted in tunable swelling kinetics and mechanical properties. Wettability and surface stiffness improve with the increase in hybrid content. The antibacterial effect was confirmed by a colony-counting assay for formulations with higher AgNPs content, exhibiting inhibitory metabolic activity against several pathogenic strains. These results suggest that PAAm/TOCNF–AgNPs (PTA) nanocomposites represent a promising mechanically adaptive candidate for wound-care applications. Full article

Bubble bursting at liquid surfaces was investigated experimentally using high-speed imaging at 25,000 fps and micro-particle image velocimetry (µ-PIV) at up to 4000 flow fields per second. Three fluids with distinct rheological properties were studied: a viscous Newtonian fluid (Emkarox, η₀ = 0.072 Pa·s) and two non-Newtonian fluids (highly viscous Carboxymethyl Cellulose, HV CMC, η₀ = 0.53 Pa·s, and viscoelastic Polyacrylamide, PAAm, η₀ = 57.17 Pa·s). Bubble radii ranged from 1.2 to 4.0 mm, with corresponding lifetimes spanning from O(10⁻²) to O(10¹) s depending on fluid properties. The relationship between bubble size and lifetime at the air–liquid interface was quantified for the non-Newtonian fluids, using the Newtonian fluid as a reference. µ-PIV measurements further captured the rapid dynamics of bubble bursting beneath the interface in the liquids. These findings provide new insight into the complex interfacial mechanisms governing bubble rupture and fluid motion. Full article

To address the global challenge of desertification, it is essential to develop sustainable and biodegradable materials for sand fixation to support ecological restoration in arid regions. In this work, a CNS/PAM biocomposite system was constructed through the supramolecular assembly of highly flexible two-dimensional cellulose nanosheets (CNS) and polyacrylamide (PAM). Benefiting from the flexible layered structure of CNS and the abundant hydroxyl and carboxyl groups on their surface, a conformal coating and an interparticle bridging network were formed via hydrogen bonding and coordination interactions with mineral cations. The introduction of PAM further regulated the hydrogen-bonding network, which improved structural uniformity and mechanical integrity. The resulting composites showed strong resistance to both wind and water erosion (erosion loss < 0.1%) and reached a compressive strength of up to 0.23 MPa, while maintaining good environmental compatibility. This study clarifies the structure–interaction–property relationships of cellulose nanosheet-based supramolecular assemblies and provides a new theoretical basis and practical pathway for designing biodegradable sand-fixing materials. Full article

Biomass represents a vital and sustainable resource for developing renewable materials with the potential to replace petroleum-based chemicals. Paulownia wood has high cellulose content and a loose wood structure, giving it natural advantages as a biomass material. Therefore, in this study, Paulownia wood was selected as a lignocellulosic feedstock. An integrated pretreatment process combining a deep eutectic solvent (DES) with an organic solvent was employed to efficiently remove lignin and hemicellulose, yielding cellulose-enriched residues. Subsequently, high-intensity ultrasonication was applied to convert the residues into cellulose nanofibers and nanocrystals. Using the extracted cellulose and nanocellulose, a dual-crosslinked network composite hydrogel was fabricated. The structural, mechanical, thermal, swelling, and conductive properties of the hydrogel were systematically investigated. The results show that, compared with the blank group hydrogel, the addition of nanocellulose increased the maximum tensile strength and tensile strain of the composite hydrogel by approximately 113% and 81%, respectively; meanwhile, the compressive strengths of the nanocellulose-based hydrogels (0.04575–0.09060 MPa) are higher than that of the blank group hydrogel (0.04235 MPa), confirming that the incorporation of nanocellulose significantly enhances the mechanical strength and elasticity of the hydrogel. The introduction of an AlCl₃/ZnCl₂ solvent system imparts appreciable electrical conductivity. Furthermore, the composite hydrogel maintains structural integrity after full swelling, indicating good dimensional stability and reusability. This work not only presents a green and efficient strategy for valorizing Paulownia biomass but also offers a novel design route for high-performance conductive hydrogel materials, highlighting their potential application in areas such as flexible electronics and energy storage. Full article

Conductive hydrogels are attractive for flexible electronics, but their practical use is often limited by resistance drift during repeated deformation and performance degradation at low temperatures. Here, core–shell polyaniline-coated polyacrylonitrile (PANi@PAN) electrospun nanofibers were incorporated into a polyacrylamide/hydroxypropyl cellulose (PAM/HPC) hydrogel matrix to construct a hybrid conductive network. The PANi shell serves as an electronic pathway alongside ionic conduction in the hydrated polymer network, leading to markedly improved electromechanical stability. The resistance drift is about 11% after 2000 stretching–relaxation cycles at 0–100% strain, about 12 times lower than that of the nanofiber-free hydrogel. Stable electrical responses are maintained under large deformation, with a resistance drift as low as 3.3% over a strain range of 0–400%. The hydrogels show a conductivity of 0.32 S m⁻¹ while retaining high stretchability (>600%). An ethylene glycol/water binary solvent is used to suppress ice formation and improve moisture retention, allowing stable electromechanical performance at −15 °C over 500 cycles. The hydrogel also adheres reliably to human skin (about 10.25 kPa) and functions as a conformal strain sensor without extra fixation. Full article

Circular pipe-jacking construction in gravel strata faces significant technical challenges, including high frictional resistance, elevated permeability, and susceptibility to collapse. Optimizing the formulation of thixotropic slurry is crucial for improving the construction quality and efficiency of such projects. This study, based on the Ruyang Water Supply Project of the North Main Canal in the Qianping Irrigation Area, Henan Province, China, systematically investigated slurry formulation using bentonite, soda ash, sodium carboxymethyl cellulose (CMC), polyacrylamide (PAM), and shell powder as raw materials. An orthogonal experimental design was employed to optimize the mix proportions, and the friction-reduction performance was validated through drag-friction model tests. The results indicate that the optimal slurry formulation is: bentonite 8%, soda ash 0.3%, CMC 0.2%, PAM 0.15%, shell powder 4%, and water 87.35%. This formulation exhibits excellent fluidity and thixotropy, facilitating the formation of a stable slurry film. Consequently, the friction coefficient between concrete specimens and gravel soil was reduced by 35.6%. The inclusion of shell powder significantly enhanced the slurry’s cohesiveness and improved the anti-seepage capacity of the surrounding stratum due to its filling effect. The optimized thixotropic slurry effectively mitigates frictional resistance during pipe jacking in gravel strata and enhances the formation’s resistance to collapse. The findings of this study provide a viable technical reference for pipe-jacking projects under similar geological conditions. Full article

To address the problems of complex composition, significant property variations, and difficult and costly harmless treatment of oil-contaminated sludge in oil and gas field development, its good compatibility with the formation is leveraged to formulate it with oilfield water into an oil–water profile control agent. This reduces the cost of harmless treatment and enables resource utilization of hazardous waste. The properties of oil-contaminated sludge were evaluated experimentally. Suspending agents and stabilizers were selected according to the oil–water profile control agent preparation process, the corresponding agents were prepared, and the system was experimentally tested. The experimental results show that the suspending agent carboxymethyl cellulose (CMC) and partially hydrolyzed polyacrylamide (HPAM), and the dispersant Dodecyl dimethyl betaine (BS-12) are used to prepare oil–water profile control agent based on the selected sulfonated mud oily sludge and ground system oily sludge. The optimal formulation of profile control agent is as follows: (1) 50% ground system oily sludge +50% oilfield produced water + 0.2% CMC + 1.0% BS-12; (2) 50% sulfonated mud system oily sludge +50% oilfield produced water + 0.1% HPAM + 1.0% BS-12. The preparation of a profile control agent from oily sludge is a viable low-cost resource treatment strategy for oily sludge, which is of great significance for the environmentally friendly treatment of oil and gas field development. Full article

Sorghum, the fifth major global cereal, has potential as a source crop in temperate regions. To completely use sorghum bagasse, the ideal enzyme cocktail aims to identify and select the contributed enzymatic system. This study investigated the enzymatic system of Clostridium cellulovorans cellulosome and noncellulosomal enzymes using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and liquid chromatography–tandem mass spectrometry LC-MS/MS. Enzyme solutions from treated and untreated sorghum bagasse were prepared and compared based on carboxymethyl cellulase (CMCase) activity. As a result, the enzyme solution derived from untreated sorghum bagasse had the highest activity. Protein bands from each C. cellulovorans culture showed distinct patterns on SDS-PAGE examination: three enzyme fractions, including culture supernatants, crystalline cellulose (Avicel) bound, and unbound fractions. These results suggested that untreated sorghum bagasse induced a variety of cellulosomal and uncellulosomal proteins. On the other hand, 5% or 10% sorghum supernatants could not induce Avicel-bound proteins, including the cellulosome, although even 5% sorghum juice induced three major bands: 180 kilodalton (kDa), 100 kDa, and 70 kDa, respectively. In contrast, cellobiose induced three major bands, while the total number of all isolated proteins from the cellobiose medium was the most limited among all culture media. More intriguingly, our investigation detected one cellulosomal protein, hydrophobic protein A (HbpA) and three noncellulosomal enzymes, indicating that glycosyl hydrolase family 130 (GH130) was identified as a biomass-induced enzyme in good accord with previously published proteomic studies. Therefore, the proteomic dataset generated in this study provides us a foundation for future computational approaches, including machine learning-based prediction of optimal enzyme cocktails for target biomass degradation. Full article

Conventional agricultural practices, based on intensive irrigation and heavy fertilizer and pesticide inputs, are increasingly incompatible with climate change, soil degradation, and sustainability goals. Hydrogels have emerged as promising soil amendments to improve water and nutrient management, and fall broadly into two categories: synthetic polyacrylate/polyacrylamide-based systems and natural biobased hydrogels derived from polysaccharides such as alginate, cellulose, and chitosan. The latter, often obtained from agro-industrial residues, offer biodegradable and potentially lower-impact alternatives to persistent synthetic matrices. This review analyzes recent advances in the design and application of nanocomposite hydrogels in agricultural crops, with emphasis on high-value systems such as tomato, chili pepper and maize. Representative studies show that hydrogel–nanofertilizer formulations can increase soil water retention in tomato from ~55–56% to ~78–79%, nearly double swelling capacity in wheat, reduce irrigation requirements by around 15% in legumes, and improve plant biomass by ~30–40% under drought conditions. In parallel, nanocomposite hydrogels loaded with micronutrients, phytochemicals or biostimulants can enhance nutrient uptake, provide 36–80% protection against Fusarium wilt, and reduce postharvest pathogen growth by up to ~90%, while in some cases improving the nutraceutical quality of fruits. These outcomes illustrate a dual mechanism of action in which the hydrogel matrix acts as a micro-reservoir that buffers water and nutrients, whereas nano- and phytochemical components operate as physiological eustressors that modulate plant defense and metabolism. Finally, we discuss environmental and translational challenges, including hydrogel biodegradation pathways, the long-term fate and ecotoxicity of released nanoparticles, regulatory uncertainty, and market and field acceptance. Addressing these gaps through integrative agronomic, ecotoxicological, and regulatory studies is essential to ensure that nanocomposite hydrogels evolve into truly sustainable smart carriers for fertilizers, pesticides, and biostimulants in future cropping systems. Full article

Polymeric stabilizers play a critical role in enhancing the stability and performance of firefighting foams. This study evaluated the influence of three polymeric stabilizers (xanthan gum, XG; polyacrylamide, PAM; sodium carboxymethyl cellulose, CMC-Na) on the performance of foam solutions formulated with a zwitterionic short-chain fluorocarbon surfactant. The investigation focused on three performances: interfacial properties, apparent viscosity (at a fixed rotational speed), and foam performance, employing interfacial tension analysis, viscosity measurement, dynamic foam analysis, and foam drainage testing. Results indicate that XG and CMC-Na slightly decrease interfacial activities, reducing spreading coefficients 6.34–15.78% and 0.68–6.35%, respectively. However, these polymeric stabilizers substantially increase apparent viscosity through hydrogen bond network formation, which effectively mitigates foam coarsening and drainage. When adding 0.10 wt.% XG, the foam solution exhibits a characteristic coarsening time of 724.64 s and a 25% drainage time of 1519.15 s. Conversely, PAM exhibits a concentration-dependent dual effect. When below 0.06 wt.%, PAM enhances interfacial properties and foam stability. However, at elevated concentrations, excessive PAM aggregates at interfaces and forms entangled networks that inhibit surfactant adsorption. This impairs foam formation and accelerates foam structural evolution, increasing variation in bubble size and promoting foam drainage by 8.63–57.88%. These findings provide crucial reference for applying polymeric stabilizers in short-chain fluorocarbon surfactant systems. Full article

Cationic polyelectrolytes, characterized by positively charged functional groups, play an essential role in industries ranging from food solutions, water treatment, medical, cosmetic, textiles and agriculture due to their electrostatic interactions, biocompatibility, and functional versatility. This paper critically examines the transition from petroleum-based synthetic polymers such as poly(diallyldimethylammonium chloride) and cationic polyacrylamides to sustainable natural alternatives derived from agri-forestry resources like starch derivatives and cellulose. Through a cradle-to-gate life cycle assessment, we highlight the superior renewability, biodegradability, and lower carbon footprint of bio-based polycations, despite challenges in agricultural sourcing and processing. This study examines cationization processes by comparing the environmental limitations of traditional chemical methods, such as significant waste production and limited scalability, with those of second-generation reactive extrusion (REX), which enables solvent-free and rapid modification. REX also allows for adjustable degrees of substitution and ensures uniform charge distribution, thereby enhancing overall functional performance. Groundbreaking research and optimization achieved through the integration of artificial intelligence and machine learning for parameter regulation and targeted mechanical energy management underscore REX’s strengths in precision engineering. By methodically addressing current limitations and articulating future advancements, this work advances sustainable innovation that contributes to a circular economy in materials science. Full article

Winery wastewater, characterized by high organic load, fluctuating pH, and seasonal variability, presents a major environmental challenge for sustainable water management in viticulture regions. Recent advances in bio-based polymer composites, particularly those incorporating cellulose and chitosan matrices blended with synthetic polymers such as polyacrylamide (PAM), polyvinyl alcohol (PVA), and polyethylene glycol (PEG), provide promising possibilities for effective wastewater treatment and water reuse in irrigation. This review critically explores the synthesis, structural properties, and functional performance of cellulose/chitosan-based composites, with a particular emphasis on their adsorption, flocculation, and biodegradability in the context of winery effluent treatment. Evidence from recent laboratory- and pilot-scale studies highlights the significance of pH-responsive functional groups, electrostatic interactions, and hydrogen bonding in controlling pollutant capture and regeneration efficiency. While notable removal efficiencies of these composites have been demonstrated to exceed 85–95% for COD, 80–98% for turbidity, and >90% for heavy metals, challenges remain in terms of regeneration, long-term field applicability, and scale-up. Overall, biopolymer composites represent a promising pathway toward sustainable wastewater treatment and irrigation reuse in winery operations. Full article

A polyacrylamide-based film-forming agent was synthesized via free-radical copolymerization. FT-IR spectroscopy confirmed complete monomer conversion with no detectable residual unsaturation. Systematic variation of acrylamide (AM), vinyl acetate (VAc) and cellulose content revealed that an AM mass fraction of 3.7 wt%, a VAc:AM molar ratio of 1:3 and a cellulose content of 1.6 wt% yielded an emulsion of maximal colloidal stability. Under these conditions, the agent formed coherent, moisture-resistant films that effectively encapsulated sodium-bentonite pellets, indicating its potential as an efficient inhibitor for maintaining well-bore stability during drilling operations. Full article