Colloid and Polymer Science最新文献

For the first time, functionalized okra gum with multi-aldehyde groups (OG-CHO) and carboxymethyl chitosan (CMCh) is used to create injectable hydrogels (IHs) via Schiff base reaction at 37 °C. Gelation time is optimized based on the ratio of aldehyde groups of OG-CHO to amine groups of CMCh (9 ± 3 to 2 ± 1 min). Physical characteristics such as gel content (84 ± 2) and porosity (66 ± 3) are assessed. The syringeability, injectability, and self-healing properties are evaluated qualitatively and quantitatively using a rheometer. Structural analysis is carried out by FT-IR and ¹H-NMR spectroscopy, while surface morphology and pore size (80 ± 5 µm) are examined via SEM. The swelling ratio is studied in the gel state of the IH in phosphate buffer saline (PBS) at varying pH levels of 5.5, 7.4, and 8.5, revealing a decrease in swelling ratio with increasing pH from 5.5 to 7.4 (75 ± 24 to 635 ± 20%), followed by an increase in swelling at pH 8.5 (724 ± 18.5%). Ciprofloxacin is employed as a model drug for release assays, and drug release behavior in gel forms of IH across different wound pH ranges is evaluated. The swelling and drug release behavior is described using the Korsmeyer–Peppas model, which shows non-Fickian diffusion. Furthermore, biocompatibility (cell viability > 90%), antibacterial assay, and in vitro degradation (~ 98%) are also assessed.

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The microplastic pollution caused by traditional agricultural mulch had been revealed. The application of biodegradable mulch is one of the potential ways to solve this problem. Therefore, it is significant to investigate the hydrothermal aging behavior of poly(butylene adipate-co-terephthalate) (PBAT) mulch. In this study, thermoplastic starch (TPS), TPS/talc, and talc-filled PBAT mulch were prepared. A 28-day hydrothermal aging test was conducted, and the mechanical properties, light transmission, water vapor barrier properties, hydrophobic performance, viscosity-average molecular weight, and characterization of the PBAT mulch were detected. The results showed that the original TPS-filled PBAT mulch had excellent mechanical properties, and its tensile strength and elongation at break reached 29.67 MPa and 1166.52%, respectively. The mechanical properties of the PBAT mulch were greatly reduced after hydrothermal aging. Hydrothermal aging would reduce the light transmittance of PBAT mulch to visible light, while the hydrolysis of starch would cause the opposite result. The hydroxyl group in TPS would reduce the water vapor barrier performance of the PBAT mulch. After hydrothermal aging, the viscosity-average molecular weight of the PBAT mulch decreases and the surface of the PBAT mulch was destroyed, which meant that the PBAT mulch was hydrolyzed. FTIR showed that hydrothermal aging could cause the fracture of ester groups. The TG spectral curve showed that the proportion of TPS in PBAT mulch decreased after hydrothermal aging, which meant that TPS was more easily hydrolyzed than PBAT. The results would promote the wide application of PBAT mulch.

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Fused filament fabrication (FFF) is a rapidly growing additive manufacturing technique. It is widely used in various industrial applications due to its ability to efficiently produce functional parts with complex geometrical features. Estimating the mechanical properties and dimensional accuracy is essential for the functional testing of objects fabricated using the FFF process. Several process variables influence the mechanical qualities and dimensional accuracy of objects manufactured using FFF technology. Selecting the optimal set of parameters is crucial for achieving the desired properties in the final parts. This research investigated the influence of four crucial process variables, layer thickness, extrusion temperature, printing speed, and extrusion width, on the impact resistance and shear strength of polycarbonate parts printed using the fused filament fabrication (FFF) technique. A hybrid modelling approach involving dimensional analysis (DA)–based mathematical modelling and regression-based machine learning (ML) modelling was adopted to predict the two output responses and determine the correlation between the process parameters and mechanical properties. A comparison based on various error metrics and the performance of the models suggested that ML models have higher prediction performance and accuracy than DA models. The developed prediction models exhibited significant agreement with the observed values and may be used to forecast the mechanical characteristics of FFF components while manipulating the input parameters. The findings revealed that a maximum impact strength of 66.37 J/m and shear strength of 50.43 MPa were obtained when the layer height, extrusion temperature, printing speed, and extrusion width were 320 µm, 280 °C, 20 mm/s, and 0.56 mm, respectively.

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The combination of conducting polymer and nanogold represents a cutting-edge approach in the development of efficient drug release control systems, particularly leveraging molecular imprinting technology. In this work, a conductive molecularly imprinted polymer (MIP) was electro-synthesized from 1,8-diaminonaphthalene monomers in the presence of amoxicillin as target molecule on gold nanoparticles (AuNPs). AuNPs play a crucial role in supporting the polymerization process and facilitating the characterization of material properties through various analytical techniques. Furthermore, the conductive MIP facilitates fabrication control through electrochemical parameters, enabling the specific and reversible capture and release of amoxicillin. A comprehensive drug release kinetic study was conducted, revealing a significant departure from the conventional release profile of commercial amoxicillin capsules. While typical capsules release the drug over 1 h, our conductive MIP material demonstrated a substantially prolonged release time, extending up to approximately 8 h. This prolonged-release duration holds promising implications for drug delivery applications, potentially offering improved therapeutic outcomes and patient adherence.

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Enhancing the compatibility of immiscible polymer blends is crucial to achieving optimized performance for polymer materials. This work presents a comprehensive investigation into the effect of copolymer-tethered nanoparticles (NPs) on the compatibilization of immiscible polystyrene/polymethyl methacrylate (PS/PMMA) blends. The morphology, rheological behavior, and mechanical properties of the blends were analyzed to compare the compatibilization effects of NPs tethered with block, random, and graft copolymers. Our findings indicate that block copolymer-tethered NPs exhibited superior compatibilization efficiency in contrast to random and graft copolymer-tethered NPs. Moreover, by achieving an optimized balance in selective molecular entanglement, the incorporation of 3 wt% block copolymer-tethered NPs with extended PS and PMMA blocks demonstrated the most efficient compatibilization, decreasing the size of dispersed phases from 6.42 ± 9.66 µm to 1.25 ± 0.73 µm while boosting the tensile strength of blends by 78%.

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This work presents a comprehensive investigation into the effect of copolymer-tethered nanoparticles on the compatibilization of immiscible polystyrene/polymethyl methacrylate (PS/PMMA) blends.

In this study, three polycarboxylic acids with varying numbers of carboxyl groups were employed to crosslink polyvinyl alcohol (PVA): malonic acid as a diacid (MA), citric acid as a triacid (CA), and 1,2,3,4-butane tetracarboxylic acid as a tetraacid (BTCA). The crosslinking abilities of these acids were compared using physical, chemical, mechanical, morphological, thermal, and swelling measurements to assess their impact on the physicochemical properties of the resulting films. Based on the degree of crosslinking, mechanical strength, and thermal stability, tetra acid demonstrated superior crosslinking performance compared to di and tri acids. The highest strength was observed in the tetra acid crosslinked film, which exhibited a 127% increase over neat PVA. Regarding thermal stability, the decomposition temperature followed the order of tetraacid (450 °C) > triacid (378 °C) > diacid (350 °C). However, in terms of swelling behavior, triacid-crosslinked film, i.e., P-CA, exhibited the highest swelling. Further, the tetra acid-crosslinked film exhibited the lowest crystallinity and a higher contact angle (104.9°) than diacid and triacid crosslinked films. Additionally, the crosslinked films displayed enhanced elasticity compared to pure PVA, with the elasticity order being diacid > triacid > tetraacid, possibly due to differences in available crosslinking sites among the crosslinkers.

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With the extensive use of manufactured sand and admixtures, it has been observed that as the shear rate increases, the shear rate–shear stress curve of some fresh wet shotcrete materials increasingly deviates from a linear correlation. It is necessary to study the rheological properties of wet shotcrete using a nonlinear model due to the large error when utilizing the Bingham model to describe the concrete. The torque-velocity curve of wet shotcrete was determined using an ICAR rheometer in this study. The experimental data was fitted using the Bingham model, Herschel-Bulkley (H-B) model, and modified Bingham (M-B) model, resulting in the determination of the associated rheological parameters. The M-B model exhibits the most optimal fitting effect, followed by the H-B model and the Bingham model. As the shear rate reaches a specific value, the M-B model consistently represents a higher degree of divergence from linearity compared to the H-B model. Furthermore, considering the limitations of the H-B model which includes varying dimension parameters, this study enhanced the calculation approach for determining the equivalent plastic viscosity based on Larrard et al.’s (Mat Struct 31:494–498, 1998) research. Ultimately, the impact of the mix parameters on the yield stress and plastic viscosity of the three rheological models was analyzed through the range approach. This study is beneficial for enhancing the comprehension of the rheological characteristics of wet shotcrete.

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The presence of numerous drugs in effluents poses the multiple challenges of removing them from effluents, quantifying them, and developing models to describe the adsorption process. In this manuscript, we present our work on the competitive sorption of sodium cromoglicate (CG) and sodium diclofenac (DF) on crosslinked chitosan particles (C-CHIT). In the Supplementary Material of this manuscript, we provide a method for simultaneously determining the concentrations of these drugs in effluents using trivial UV–Vis spectrophotometric measurements. This method was used to build sorption isotherms for the competitive sorption of these two drugs. Competitive sorption is evident in the sorption isotherms in the form of two regimes: in the first stage, the surface is saturated with CG, and after a sharp discontinuity, adsorption is governed by DF. These ternary solution two-step isotherms can be mathematically described as composed of isotherms derived from the sorption of binary solutions on C-CHIT, with the discontinuity related to their Gibbs free energies of adsorption and lateral interaction parameters. To our knowledge, there are no descriptions of competitive sorption of this kind reported in the literature.

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Phenol–formaldehyde resin can be used to improve oil recovery; its key lies in its aggregation behavior and blocking strength. However, the traditional phenol–formaldehyde resin used in the petroleum field is all prepared by phenol and formaldehyde. In order to get rid of the dependence on fossil resources and make full use of renewable biomass resources, we used the abandoned walnut shells of the unique agricultural and forestry crops in Gansu province, which contains lignin partially replaced phenol to synthesize the new sulfonated lignin-based phenol–formaldehyde resin (SLPFR). The results showed that the optimum conditions for microwave polymers were polystyrene substitution rate of 20 wt%, decomposition temperature of 160 ℃, decommissioning time of 20 min, and sodium hydroxide concentration of 0.3 mol/L. Infrared spectroscopes and scanning telescopes have shown that after disintegration, there was an increased concentration of phosphorus, which had more active spots and was more suitable for replacing phenylphenol-synthetic formaldehyde resins. LC–MS indicated the molecular mass of SLPFR and the possible structure of molecules, indicating the successful synthesis of SLPFR. In this work, the aggregation behavior and dispersion stability of SLPFR were investigated from the composition of formation water. The effects of metal cations (Na⁺, Mg²⁺, Ca²⁺) on the dispersion stability of SLPFR in formation water were determined by turbidimetry, and the effects of metal cations on the particle size and zeta potential of the SLPFR system were measured by dynamic light scattering method and electrophoretic light scattering method. The stability of the aggregate structure of the SLPFR system was calculated by combining the fractal dimension. In this paper, the surfactant + SLPFR system and partially hydrolyzed polyacrylamide (HPAM) + SLPFR system were designed for the specific conditions of oil reservoirs, and the effects of metal cations on the aggregation behavior and dispersion stability of these two systems were studied. Based on the above comprehensive analysis, aggregation models were constructed to describe the aggregation behavior and dispersion stability of the HPAM + surfactant + SLPFR system. This makes it possible to predict in real time the migration and plugging of SLPFR aggregates in formation water.

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Surface conductivity can have a significant impact on the determination of the zeta potential, but it is normally not accounted for when applying the Helmholtz-Smoluchowski or Henry models. In this study, we investigate concentrated polymer dispersions using electroacoustics and both standard models. We also pay particular attention to the influence of surface conductivity, which is characterized by conductivity measurements of the dispersion and dispersion medium. The Dukhin number as a measure of surface conductivity is calculated according to Maxwell–Wagner-O’Konski theory. Zeta potentials were determined by means of colloid vibration current (CVI) and electrophoretic light scattering (ELS) methods. It has been found that neglecting surface conductivity in standard electrokinetic models can lead to large measurement errors of up to 100% with increasing particle volume fraction. In this study, the surface conductivity is now correctly taken into account by using the conductivities of the dispersion and the dispersion medium. Alternatively, this influence can also be considered using the Dukhin number. The zeta potentials resulting from the CVI measurement are then in excellent agreement with ELS reference measurements over a wide volume fraction range.

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