Journal of Polymers and the Environment最新文献

The discharge of untreated wastewater containing dyes causes water pollution. The present study evaluated the simultaneous removal efficiency of Reactive Violet 5 (RV5) and Acid Red 98 (AR98) utilizing nanosized zero-valent iron (nZVI) incorporated with chitosan (CS) and copper (Cu) (nZVI-CS-Cu) as a novel adsorbent for the concurrent elimination of mentioned dyes. Identification of the synthesized adsorbent was studied by SEM, EDX, FTIR, XRD, and BET. The amorphous structure of nZVI-CS-Cu was proven by XRD (2θ = 44˚). The BET surface area was 110.53 m²g⁻¹. Solution pH, adsorbent dosage, contact time, initial concentration of dye, and temperature were various factors for investigating their effects on the adsorption process using central composite design (CCD). To obtain this, a linear model was selected as the best model. According to the findings, at the optimum conditions, including pH of 3.0, sorbent dosage of 0.3 g, contact time of 15 min, dye concentration of 20 mg/L, and temperature of 40 ˚C, the maximum removal efficiency was 87.80% (actual) and 87.97% (predicted). In the CCD model, adjusted R² and R² predicted were 0.9670 and 0.9634, respectively. The significance of the model was confirmed by the F-value of 288.56 and a p-value < 0.0001. Feed-forward back propagation neural network (FFBP-NN) with Levenberg–Marquardt (LM) and scaled conjugate gradient (SCG) as training algorithms were applied for predicting the percentage of dye removal. After testing different layers (2 and 3) and neurons (2, 3, 4, 5, 6, 7, 8, 9), the neurons of 8 in hidden layer 3 with mean square error (MSE) of 4.01 × 10^–20 for the LM algorithm, and neurons of 7 in the layer of 3 with MSE of 1.18 for the SCG algorithm were selected as the best layers and neurons. Excellent modeling with percent recovery close to 100 for LM (training: 100.68%, validation: 100.89%, and testing: 100.85%) and SCG (training: 100.20%, validation: 99.84%, and testing: 100.13%) was obtained. The Langmuir model with R² of 0.9993 and q_max of 52.91 mg/g and pseudo-second-order kinetics with R² of 0.9996 followed the adsorption isotherm and kinetic, respectively. It can be said that the proposed adsorbent is simple and economical with good performance, which can be used to remove different dyes from wastewater.

Oral cancer remains a significant health challenge, necessitating innovative therapeutic strategies to enhance treatment efficacy and minimize side effects. This study investigates the potential of kaempferol-loaded zein nanoparticles (KZNPs) for this purpose. Kaempferol, a flavonoid with anticancer properties, has poor water solubility, limiting its effectiveness. Zein nanoparticles (ZNPs) offer a promising delivery system for such bioactive compounds. UV-Vis spectroscopy identified Kaempferol’s absorption peaks at 347 and 253 nm, which shifted to 338 nm when encapsulated in ZNPs, indicating a change in π–π* conjugation. Dynamic light scattering (DLS) and scanning electron microscopy (SEM) confirmed that sodium caseinate (SC) stabilizes ZNPs, resulting in spherical particles with optimal size and stability. Fourier transform infrared (FTIR) spectroscopy suggested enhanced hydrogen bonding between Kaempferol and zein. Differential scanning calorimetry (DSC) revealed the absence of Kaempferol’s crystalline peaks in KZNPs. The encapsulation efficiency (EE) was 98.39%, and drug release studies showed a controlled release of 79% kaempferol over 8 h. In vitro assays demonstrated that KZNPs significantly increased Kaempferol’s cytotoxicity against PCI-13 oral cancer cells without affecting normal NIH3T3 cancer cells. Overall, these results demonstrate that our KZNPs enhanced biocompatibility and anticancer properties for oral cancer cells.

Long-chain polyesters were prepared by melt polymerization using tetradecanedioic acid (TA) and aliphatic diols containing C2-10 as raw materials. The materials were characterised using a range of analytical techniques, including tensile testing, rheological testing, dynamic mechanical analysis (DMA), wide-angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), gel permeation chromatography (GPC), and thermal gravimetric analysis (TGA). An investigation was conducted to ascertain the impact of diol chain length on a number of characteristics, including mechanical properties, crystalline structures, chemical composition, thermal stability, and thermal transition properties. All polyesters had high weight-average molecular weights (> 57000 g/mol). In addition, the crystallization temperature and melting temperature were affected by the chain length of diols. Poly(ethylene tetradecanedioate) (PETd) had a higher crystallization temperature (69.1 °C) and melting temperature (89.0 °C) compared to the other four polyesters, which may be due to its short-chain structure and the kink structures. All polyesters have the same crystal structure like polyethylene. In addition, poly(ethylene tetradecanedioate) (PETd), poly(butylene tetradecanedioate) (PBTd), and poly(octenyl tetradecanedioate) (POTd) exhibited polyethylene-like mechanical properties with comparable tensile strength and elongation at break. It is anticipated that bio-based polyesters will prove to be a highly promising material.

This research investigated the design, synthesis, and utilization of a Cu/CFHN as an effective and recyclable heterogeneous catalyst for the Huisgen click reaction in aqueous environments. The Cu/CFHN was manufactured via graft copolymerization of acrylic acid onto CMC, followed by the in situ synthesis of Fe₃O₄ nanoparticles and subsequent loading of copper ions. The Cu/CFHN was thoroughly characterized using FT-IR, XRD, SEM, TEM, EDX, XRF, VSM, and TGA, validating its structural integrity, elevated porosity, magnetic properties, and substantial copper ion adsorption capacity(28.00 wt% Cu(II)), as well as thermal stability. The Cu/CFHN catalyst was assessed in the Huisgen 1,3-dipolar cycloaddition of terminal alkynes, alkyl halides, and sodium azide, producing 1,2,3-triazoles with remarkable efficiency (yields up to 95%) under mild reaction conditions (room temperature, 6 mol% catalyst loading). The reaction exhibited significant tolerance for various functional groups, smooth progression, and elevated product yields. Water was recognized as the ideal solvent, consistent with green chemistry principles. The catalyst demonstrated exceptional stability and recyclability, maintaining catalytic activity across five successive process cycles with minimal efficiency loss (less than 5% decrease in yield). This method emphasizes the ecological and financial benefits of employing Cu/CFHN, such as the incorporation of biodegradable and biocompatible materials, reduced waste production, and streamlined reaction processing. The findings underscore the capability of Cu/CFHN as a resilient, durable, and adaptable catalyst for organic synthesis, with encouraging applications in pharmaceutical and industrial chemistry.

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The research aims to ensure the structural stability of nanocellulose-based aerogels in humid environments while imparting flame-retardant properties, alongside their inherent thermal and acoustic insulation capabilities. Building on the established flame retardancy of citric acid-based nanocellulose, our study marks a significant advancement by employing a simple and efficient methodological approach. We introduce a simple and facile technique for crosslinking CNF aerogel using a single crosslinking agent for extraction and modification. The cross-linked CNF aerogel shows a 91% porosity with a low density (0.15 g/cm³) which is also positively influenced by the morphological studies. In addition, the inclusion of citric acid into CNF improves water stability, mechanical performance (7.8 N/mm² for pure CNF and 8.9 N/mm² for cross-linked CNF aerogels), and thermal stability, while reducing the residue of the cross-linked material to 1.6% from 6.4% of pure CNF aerogel. The cross-linking of aerogel by citric acid could enhance fire resistance by lowering the production of hazardous and combustible gases. Furthermore, the cross-linked CNF aerogel was evaluated with a thickness of 40 mm, as the pure CNF aerogel demonstrated optimal sound absorption behavior at this thickness according to simulations conducted using COMSOL Multiphysics software. This work contributes to the broader understanding of how nanocellulose can be engineered for structural building applications, paving the way for further innovations in environmentally friendly aerogel technologies.

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This study aimed to develop novel bigel system utilizing a combination of guar gum (GG) as the hydrogel phase and rice bran wax (RBW)/walnut oil (WO) as the oleogel phase to mimic the characteristics of solid fats. The oleogel was prepared using RBW as the oleogelator concentrations of 8 and 9% mixed with the hydrogel phase at different ratios (30:70, 50:50, and 70:30) through defined mixing speeds (600 and 1800 rpm) to produce an emulsifier-free bigel. The effects of RBW (as oleogelator) concentration, oleogel/hydrogel ratio, and mixing speed were investigated on the microstructure, oil binding capacity, rheological properties and textural properties of bigel samples. Based on the results the highest hardness (1.84 N), spreadability (4.45 N.mm), and firmness (2.23 N) were observed in the sample prepared with 9% RBW. Increasing the mixing speed resulted in decreased adhesiveness and increased oil binding capacity. The highest adhesiveness (2.33 N.mm) and oil binding capacity (100%) were observed in the bigel containing 9% RBW and 30% oleogel. According to the obtained results the bigel prepared using 9% oleogelator and 30:70 ratio of oleogel/hydrogel at 600 rpm mixing speed demonstrated better physicochemical properties and could be recommended for food applications as a fat replacer.

A robust biodegradable packaging material was developed having superior barrier resistance to water, air, oil, grease, and microorganisms, which consisted of paper handsheets made from recycled old-corrugated container (OCC) wastes and collagen hydrolysate by upcycling leather wastes to reduce dependence on conventional packaging materials. The dechroming process of leather waste using 10% NaOH exhibited remarkable efficiency, achieving a 99.98% reduction in chromium content (< 44 ppb) within the World Health Organization’s recommended range. A coating recipe was formulated using collagen hydrolysate, chitosan, and glycerin (20%C-Ch-Gly) and applied on the OCC handsheets, demonstrating excellent barrier properties against hot oil, grease, and organic solvents (Kit rate 12). The developed packaging materials’ water vapor and air permeability decreased significantly by 150- and 10-fold, while tensile and burst strength increased by 140.84% and 77.73% compared to uncoated handsheets. The contact angle for water and organic solvents increased by 49.14% and 47.2%, ensuring excellent solvent repellency while maintaining a smooth and even morphological structure due to reduced average roughness by 76.67%. The optimized packaging material exhibited no cytotoxicity, displayed excellent antimicrobial properties, and was completely biodegraded in 11 weeks. This study demonstrated the potential of bio-based packaging as a viable alternative to hazardous, non-biodegradable plastics commonly used globally through upcycling leather and paper waste.

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Thermoplastic polyurethane (TPU) is a unique polymer known for its excellent physical and chemical properties including exceptional elasticity and durability, excellent abrasion resistance and resistance to oil, water, acids and alkalis, making it indispensable in various industries. In recent years, growing environmental concerns have let to the development of bio-based thermoplastic polyurethane from renewable resources which provide a sustainable alternative to conventional fossil-based TPUs. This study investigates the melt spinning process of two types of TPU: Desmopan 385E, a conventional TPU, and Desmopan CQ33085AUEC, a partially bio-based TPU, focusing on their potential for high performance multifilament yarns. A comprehensive study evaluated their thermal, rheological and mechanical properties, as well as their processability at different drawdown ratios (DDR). Thermogravimetric analysis (TGA) revealed differences in decomposition temperatures and thermal stability while melt flow rate (MFR) testing optimized melt spinning parameters. Rheological measurements showed viscosity reductions of up to 90% after spinning, reflecting structural transformations such as chain alignment and scission, with implications for processing and yarn performance. Both TPU types were successfully processed into multifilament yarns under comparable spinning conditions, achieving process speeds of up to 2000 m/min. Mechanical tests revealed differences in tensile strength and elongation, with the bio-based TPU achieving mechanical properties comparable to or 7,4% better in tensile strength than those of its conventional counterpart, highlighting the potential of bio-based TPU as a sustainable alternative for technical textile applications.

Hydroxyl-terminated poly(L-lactic acid) (PLLA-OH) and poly(butylene carbonate) prepolymer (PBC-OH) were synthesized via ring-opening(ROP) polymerization of lactide and ester exchange polymerization of dimethyl carbonate (DMC) and 1,4-butanediol (BDO), respectively. Subsequently, a chain extension reaction was conducted using diisocyanate as a chain extender to produce a biodegradable multiblock copolymer ester PLLA-PBC. The structural characteristics and molecular weight of PLLA-PBC with different block lengths and mass fractions were analyzed by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (¹H-NMR) and gel permeation chromatography (GPC). The impact of PLLA-PBC’s structure on its properties was examined through various characterization techniques, including differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and tensile testing. The DSC findings revealed that the glass transition temperature of the multiblock copolyester lies between those of PLLA-OH and PBC-OH, with variations in component content leading to a reduction in crystallinity. In addition, tensile tests showed that the addition of PBC segments significantly increased the elongation at break of PLLA.

Climate change is one of the most complex and time-sensitive crises humanity is facing, thereby driving a quest for more sustainable product alternatives across all sectors. In hygiene-critical sectors like medicine, the development of sustainable materials is imperative because of the predominant use of single use plastics. Polylactic acid (PLA) has emerged as a bio-based alternative for clinical applications because of its degradation profile. To further enhance antibacterial properties and sustainability performance, a novel biocomposite based on PLA with hemp hurd filled with silver nanoparticles (AgNP) was developed. Here we present a life cycle assessment (LCA) based on ISO 14040 and 14044 to evaluate the added value of the antibacterial biocomposite compared to conventional antibacterial materials from an environmental perspective. The environmental impacts are analyzed in comparison to virgin PLA, fossil-based polypropylene (PP) and high-density polyethylene (HDPE) combined in a disinfecting wipes and sterilized application. Our results show that the novel biocomposite has in general higher environmental impacts than its counterparts. Notably, our findings suggest a significant impact derived from high energy demand required for AgNP synthesis. To be able to compete with other materials, the energy demand needs to be minimized, which should be the focus of further research.