Colloid and Polymer Science最新文献

This study presents a systematic optimization of zinc-copper sulfide (ZnS:CuS) nanocomposites aimed at achieving smaller hydrodynamic size, improved polydispersity, and enhanced colloidal stability for efficient adsorption of Reactive Black 5 (RB5) dye from aqueous solutions. The effects of key synthesis parameters, including pH, temperature, reagent addition rate, and stabilizer concentration, were comprehensively investigated. Under optimized conditions of pH 5, 80 °C, 5-min reagent addition, and 1% polyvinyl alcohol (PVA) stabilizer, the nanocomposite achieved a minimum hydrodynamic size of 190 nm, a polydispersity index (PDI) of 0.37, and a zeta potential of − 29.7 mV, confirming high stability. Batch adsorption experiments demonstrated a maximum RB5 removal efficiency of 96% at pH 3, with adsorption equilibrium reached in 70 min. The adsorption process followed the Langmuir isotherm model (R² = 0.9996) with a maximum adsorption capacity (q_max) of 153 mg/g, and kinetics were best described by the pseudo-second-order model (R² = 0.96), indicating chemisorption. These findings highlight the potential of optimized ZnS:CuS nanocomposites as effective adsorbents for dye-laden wastewater treatment applications.

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This work reports on a highly sensitive and temperature-adaptive gellan gum/sodium lignosulfonate-modified hydrogel (PGL hydrogel) aimed at developing materials suitable for wearable sensors. By introducing gellan gum into the polyacrylamide (PAM) matrix, an interpenetrating network structure was formed, significantly enhancing the mechanical properties of the hydrogel. Subsequent post-treatment with a sodium lignosulfonate solution further improved the conductivity of the hydrogel to 0.48 S/m. As the core functional material for wearable sensors, this hydrogel exhibits a wide strain detection capability of approximately 400%, with a gauge factor (GF) of 3.79 in the 0–200% strain range and 5.16 in the 200–400% range. Notably, the material maintains synergistic stability in mechanical properties, conductivity, sensitivity, and response time across a wide temperature range of –20–60 ℃. It provides robust support for its use as a stable and sensitive strain sensor.

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Thermoplastic polyether ester elastomer (TPEE) foams fabricated using supercritical carbon dioxide (scCO₂) as a physical blowing agent exhibit promising potential for enhancing material lightweighting and resilience performance. However, the poor dimensional stability of TPEE foams limits their industrial applications, primarily due to the pronounced relaxation behavior of the polyether soft segments in TPEE at room temperature and the pressure differential between the interior and exterior of the cells caused by the significant diffusion rate disparity between CO₂ and air. To address the shrinkage issue of TPEE foams, this study focuses on these two shrinkage mechanisms and successfully prepares TPEE microcellular foams with excellent dimensional stability by melt-blending TPEE with polypropylene (PP) and carbon nanofiber-modified polypropylene (PP/CNF), respectively, using scCO₂ as the blowing agent. Under foaming conditions at 140 °C, the TPEE/PP10 foam achieves an expansion ratio of 18.6 with a shrinkage rate of only 15.5%, while the TPEE/PP/CNF10 foam exhibits an expansion ratio of 20.0 and a remarkably low shrinkage rate of 5.3%. These results represent significant improvements compared to pure TPEE foam, which shows merely an 8.7 expansion ratio and a high shrinkage rate of 62.7%. The incorporation of PP and CNF not only reduces cell size to varying degrees but also induces a synergistic effect through altered crystallization behavior and the reinforcing effect of CNF at the cell walls. This synergy effectively suppresses molecular chain relaxation while substantially enhancing the cell walls’ resistance to gas pressure differentials.

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Hot melt adhesives are utilized in a variety of industries because to their solvent-free, strong adhesion and rapid curing. With the increasing awareness of environmental protection, biodegradable hot melt adhesives have received attention. Herein, chlorinated poly(propylene carbonate) (CPPC)/poly(butylene succinate) (PBS)/poly(lactic acid) (PLA) blends were prepared using diphenylmethane diisocyanate (MDI) as reactive compatibilizer. Thermogravimetric analysis (TGA) demonstrated that adding PLA improved the thermal stability of the blends. From rheological tests, the melt elasticity and viscosity of the blends at 170 ℃ were enhanced after PLA was added. The tensile strength of CPPC/PBS/PLA/MDI blends reached 47.9 MPa as 32 wt% of PLA was added. When PLA content was 16 wt%, the blends exhibited high adhesion strength (13.97 MPa), which was much higher than that of common commercial products. In addition, the enzymatic degradation tests showed that the blends had biodegradability. Therefore, CPPC/PBS/PLA/MDI blends have the potential to be used in biodegradable hot melt adhesives.

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CPPC/PBS/PLA/MDI blends with different PLA contents were prepared by in situ compatibilization. The biodegradable CPPC/PBS/PLA/MDI blends had good mechanical and adhesive properties.

Organic wastewater pollution and bacterial contamination are increasingly causing social concerns. The development of nanostructured ZnO is critical for creating effective antibacterial and photocatalytic materials. In this study, ZnO nanofibers (ZnO NFs) were successfully fabricated using zinc acetate dihydrate (Zn (CH₃COO)₂) as the zinc source and polyvinylpyrrolidone (PVP) as the template through electrospinning combined with calcination. Before synthesizing the ZnO NFs, Zn (CH₃COO)₂/PVP nanofiber membranes were optimized using electrospinning to ensure effective nanofiber formation. The synthesis of ZnO NFs was validated through scanning electron microscope equipped with an energy dispersive spectrometer (SEM & EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy analysis, and X-ray photoelectron spectrometer (XPS). The average diameter of the zincite phase ZnO NFs was approximately 68 ± 12 nm, and the nanofibers were composed of polycrystalline ZnO. The results demonstrate that the degradation rate of the prepared ZnO NFs was 97.97% ± 1.28% for Rhodamine B (Rh B) after 2 h of UV irradiation, and the antibacterial rates were 96.22% ± 1.59% and 99.46% ± 0.73% against Escherichia coli and Staphylococcus aureus, respectively. In addition, a potential mechanism of photocatalytic degradation of RhB by ZnO NFs through photocatalytic active substance trapping experiments was investigated. In conclusion, this study provides an effective approach for developing nanomaterials for dye degradation and antibacterial applications.

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This study explores the shear-induced reversible gel behaviour of suspensions containing silica nanoparticles and poly(ethylene oxide) (PEO). When subjected to vigorous shaking, these mixtures exhibit interesting shear thickening, transitioning from low-viscosity fluids to ‘shake-gels’ and then reverting back to liquid after some time. Rheological measurements conducted at constant shear rates reveal a significant increase in viscosity by several orders of magnitude occurring at specific time points during the process. Followed by that, lowering the shear rate is implemented to understand the relaxation behaviour. The investigation specifically examines the influence of various ions from the Hofmeister series on the gelation and relaxation dynamics of these suspensions. Results indicate that salts positioned on the right-hand side of the Hofmeister series, known as salting-in agents, facilitate quicker gelation and slower relaxation of the shake gels. Conversely, salts on the left-hand side, referred to as salting-out agents, lead to slower gelation and faster relaxation. These observations are attributed to the distinct effects that different salts exert on the conformation of PEO chains. Salting-in agents induce swelling of the polymer chains, enhancing their ability to interact and bridge between silica nanoparticles effectively, thus promoting rapid gelation and sustaining the gel structure for extended periods. In contrast, salting-out agents cause the polymer chains to collapse, reducing their bridging efficiency and resulting in delayed gelation along with a more rapid return to the fluid state during relaxation. Understanding the role of specific ions in modulating the gelation and relaxation behaviour of colloidal-polymer suspensions provides valuable insights for tailoring material properties in various applications, including drug delivery, oil drilling, environmental restoration, coatings, and soft matter engineering.

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Flocculation technique is extensively adopted in the tackling of sulfide mineral processing wastewater, which contains abundant suspended solids and heavy metal ions. The functional groups of polymeric flocculants significantly influence the interactions between flocculants and pollutants. Herein, self-assembled monolayers (SAMs) terminated with − NH₂, − OH, − COOH, and − CH₃ and in situ polymerization coating of acrylamide exclusively containing − CONH₂ were fabricated via the vapor-phase deposition, self-assembly molecular membrane, and atomic transfer radical polymerization methods. X-ray photoelectron spectroscopy, water contact angle measurements, and AFM imaging were utilized for the characterization of functionalized surfaces. The adsorption behavior of kaolin and Pb²⁺ on these surfaces was explored using quartz crystal microbalance with dissipation (QCM-D). The amount of kaolin adsorbed on functionalized surfaces followed the sequence of − CONH₂ (∆f of − 1360.55 Hz) >  − NH₂ (∆f of − 395.43 Hz) >  − OH (∆f of − 181.31 Hz) >  − COOH (∆f of − 1.75 Hz) >  − CH₃ (∆f of − 0.1 Hz). The polymer coating with acrylamide (CONH₂-functionalized surface) with a specific molecular weight exhibited strong bridging effect, capturing quantities of kaolin. The amino group underwent protonation to form NH₃⁺, combining with the negatively charged kaolin through electrostatic attraction. These indicated that both the bridging effect of flocculants and the electrical neutralization between flocculants and particles were critical factors influencing the settlement of kaolin. For Pb²⁺, its adsorption amount on functionalized surfaces followed the order of − COOH (∆f of − 1.53 Hz) >  − OH (∆f of − 1.27 Hz) >  − CH₃ (∆f of − 0.34 Hz). The carboxyl group played a critical role in facilitating the adsorption of Pb²⁺ through chelation and electrostatic interaction, confirming its function as an active site. Our findings provide profound insights into the structure–activity relationship of flocculants, underscoring the importance of designing efficient flocculants for wastewater treatment.

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Understanding the behavior of PVC microplastics under UV light and their interaction with antibiotics is critical for evaluating their environmental impact. Herein, a systematic investigation reveals the adsorption behavior of UV-aged PVC (UV-PVC) microplastics toward ofloxacin (OFX), focusing on compositional and morphological changes and their adsorption behavior post-aging for 30 days. The UV aging process increased the oxygen-to-carbon (O/C) ratio of PVC from 0.23 to 1.17, along with increased oxygen-containing functional groups (− OH, − C = O) that governed the interaction behavior leading to a significant improvement in adsorption capacity reaching 38.98 mg/g compared to 18 mg/g at equilibrium compared to pristine PVC (P-PVC). The enhanced interaction was particularly effective at neutral pH, where hydrogen bonding and electrostatic interactions were optimum as confirmed by DFT calculation. These findings contribute to profiling the environmental behavior of microplastics and assessing their role as a vector for emerging pharmaceutical pollutants.

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A new MoS₂-PDA/PVDF ultrafiltration membrane was prepared by the thermotropic phase separation/non-solvent-induced phase separation (EIPS/NIPS) method. The effects of the addition of MoS₂-PDA on the hydrophilicity, microscopic morphology, and flux, flux recovery, retention, and anti-fouling properties of the composite membranes with dye wastewater and bovine serum albumin (BSA) solution were investigated. The results showed that compared with the pristine membrane, the maximum water flux of MoS₂-PDA-modified membrane was 107.8 L/(m²‧h), which was 33.58% higher; the retention rates of BSA and various dyestuffs in this membrane were 92% and 95.2%, which were 10.2% and 3.6% higher, respectively; the highest flux recoveries were 88% and 84.6%, both increased by 10%. This indicates that the modified membrane provides a reference for extending the service life of ultrafiltration membranes and can achieve efficient separation and resource recovery of small molecule wastewater.

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A recent study focuses on a significant deficiency in bone tissue engineering by creating polymer-based composite materials with improved thermal resistance and mechanical characteristics for use in medical contexts. Although polypropylene (PP) and poly(methyl methacrylate) (PMMA) blends are widely utilized, their mechanical strength and thermal resistance are insufficient, thereby limiting their suitability for load-bearing implants. We synthesized new composite materials by incorporating a sol–gel-produced blend of hydroxyapatite (80 wt.%), carbon fiber (10 wt.%), and boron carbide (10 wt.%) into PP/PMMA matrices in different weight proportions (25/75 and 75/25 wt.%) and varying amounts (10–30 wt.%). Thermogravimetric analysis showed a 20% increase in thermal stability, with the temperature at which degradation begins rising from 265 to 300 °C for composites containing 30 wt.% reinforcement. Results from mechanical testing showed a 15% rise in hardness (as measured by the Brinell HB30 method) and a 25% decrease in wear rate for the 75PMMA/25PP composite reinforced with 20 wt.% of the material, which was attributed to uniform distribution and strong interfacial bonding as confirmed by scanning electron microscopy–energy dispersive spectroscopy (SEM–EDS). X-Ray diffraction (XRD) and Fourier-transform infrared (FTIR) analysis revealed increased crystallinity and PO₄³⁻/B–C bonding, which correlated with enhanced performance. These results demonstrate the potential of HAp/CF/B₄C-reinforced PP/PMMA composites as long-lasting biomaterials for orthopedic and dental implants, featuring enhanced thermal and mechanical properties relative to traditional blends.

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