Journal of Polymers and the Environment最新文献

The strategic incorporation of renewable resources in polyurethane foam synthesis emerges as an innovative approach to minimize carbon footprint. Recent advancements in bio-based lactide production and the molecular architecture of polylactide have facilitated the development of high-performance polyurethane foams through the integration of renewable resource. In this study, polylactide (PLA)-based polyols with molecular weights ranging from 500 to 1500 g/mol and functionalities of 2 and 3 were synthesized via the ring-opening polymerization of L-lactide, and were subsequently employed as the sole polyol component in the preparation of bio-based rigid polyurethane foams (RPUFs). The physicochemical properties of the polyols, foaming behavior, as well as the mechanical performance, cellular structure, and thermal properties of the bio-based RPUFs were thoroughly characterized. Results indicated that the reactivity of PLA-based polyols exhibited a positive correlation with their functionality while demonstrating an inverse relationship with their molecular weight. Notably, tPLA500 exhibited optimal reactivity with a viscosity of 1107 mPa·s. The elevated reactivity facilitates the gelling reaction during the foaming process, while the lower viscosity enhances foam expansion. This synergistic effect improves cellular uniformity and the curing process, yielding a bio-based RPUF with intact cellular structure. This optimized morphology enables the bio-based RPUF to achieve a compressive strength of 384 kPa and a thermal conductivity of 0.036 W/(m·K), demonstrating its potential as a high-performance biobased thermal insulation material.

Fruit and vegetable wastes represent a rich source of unconventional carbohydrates with applications in pharmaceuticals, packaging, tissue engineering, and other industrial sectors, offering sustainability, cost-effectiveness, health benefits, and support for a circular economy. While common starch serves as the main source of dietary energy, non-starch polysaccharides (NSPs), such as cellulose, hemicellulose, and pectin, have diverse glycosidic bonds and complex architectures that render them indigestible by humans. These NSPs, which constitute the plant cell wall, are valued for their functional properties, including modulation of the gut microbiota and antioxidant activity. This review provides a detailed comparison between NSPs extracted from fruit and vegetable waste and those obtained from conventional sources. We demonstrated that NSPs obtained from food waste have significant advantages in terms of extraction efficiency, cost-effectiveness, and environmental impact, while maintaining essential functional and structural characteristics. Their versatility is reinforced by innovative applications as excipients in drug delivery systems, wound-healing scaffolds, biodegradable packaging, bioadhesives, flocculants, and adsorbents. Additionally, using agro-industrial residues as raw materials reduces dependence on primary resources, minimizes waste generation, and promotes sustainable development. We describe both established and emerging green extraction techniques and correlate the molecular characteristics of NSPs with their performance in pharmaceuticals, tissue engineering, and controlled-release agents. Taken together, these insights reinforce the key role of NSPs derived from fruits and vegetables in advancing a truly circular economy.

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Tissue engineering technology has been developed for bone damage solutions by applying biomaterial-based scaffolds, possessing good biocompatibility and mechanical properties. The use of polymeric biomaterials together with conductive carbon biomaterials can be considered as a potential candidate to increase the mechanical strength and other physicochemical properties of the scaffold. In this research, bone scaffolds were developed using collagen extracted from king cobia fish, hydroxypropyl methylcellulose (HPMC), and poly(vinyl alcohol) (PVA), with the addition of multi-walled carbon nanotubes (MWCNTs) and reduced graphene oxide (rGO) materials. The scaffolds were fabricated using freeze-drying and physicochemically characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, mechanical properties, wettability, porosity, swelling, and degradation rate. The findings indicated that the scaffolds were porous and had interconnected structures with a mechanical strength of about 9 MPa, which is compatible with trabecular bone. The scaffolds also had a high porosity of up to 90%, high swelling up to 300%, and a degradation rate with a mass loss of less than 20% in 28 days. The scaffolds exhibited hydrophilic properties with a water contact angle of less than 90^o. The conductivity characteristics of the scaffolds were evaluated through electrochemical measurements using cyclic voltammetry (CV), resulting in conductive scaffolds characterized by the formation of redox peaks. These results suggest that the fabricated scaffold could be a potential candidate in bone tissue engineering applications.

Herein, we report high-performance, 100% biobased nanocomposites prepared using a chemical and solvent-free approach. Lignin was used to synthesize oxygen-functionalized carbon nano-onion (CNO) using a Joule heating method. CNO was then co-extruded with polylactic acid (PLA) and wood flour to prepare nanocomposites without the pretreatment of wood or coupling agents. It showed that the addition of CNO can simultaneously improve the tensile strength, tensile modulus, impact strength, and ductility of the composites. Additionally, the CNO-containing composite had enhanced thermal stability, flame retardancy, and reduced water absorption. Our investigation indicates that the superior reinforcement effect observed in the CNO-reinforced composites is attributed to the role of CNO as a coupling agent and interfacial modifier. Turbostratic graphene structure of CNO with amphiphilic surface properties provides both structural integrity and excellent chemical competitiveness. At the same time, the quasi-sphere geometry of nanoparticles offers a high interfacial area and a dimensionless interface.

Access to clean water is increasingly critical due to escalating pollution from industrialization and population growth. This study presents the development of advanced cellulose acetate (CA)-based membranes for water filtration through an integrated approach combining electrospinning, hot pressing, and cellulose nanocrystal (CNC) functionalization. A 12 wt% CA solution in a 4:1 acetone/acetic acid mixture was electrospun under optimized conditions (1 mL/h, 15 cm, 35–70% relative humidity) to produce uniform, bead-free nanofibrous mats. Subsequent hot pressing at 100 °C and 20 bar yielded denser membranes with enhanced mechanical durability and reduced pore size. Functionalization with CNCs and TEMPO-oxidized CNCs (CNC_TEMPO) further improved performance. Structural characterization confirmed the successful TEMPO oxidation of CNCs, as evidenced by FTIR bands at 1730 and 1604 cm⁻¹ and a carboxyl content of 0.56 ± 0.04 mmol/g, enhancing nanocrystal dispersion and interfacial adhesion within the CA matrix. Moreover, SEM images showed denser and more homogeneous fiber morphology after hot pressing and CNC_TEMPO incorporation, as well as higher tensile strength values, indicating structural reinforcement. These changes led to a reduction in water contact angle (from 104° to 37°) and filtration time from 100 min to under 30 s. Filtration tests showed improved rejection of 2.0 μm particles (92%) and efficient methylene blue dye removal (up to 95%) in membranes with 3 wt% CNC_TEMPO. To the best of our knowledge, this is the first study to combine electrospinning, hot pressing, and TEMPO-oxidized cellulose nanocrystals in cellulose acetate membranes to simultaneously enhance wettability, mechanical stability, and filtration performance using a fully bio-based system. This integrated strategy offers a promising route for fabricating high-performance, multifunctional membranes for sustainable water treatment applications.

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This work studied the transformation of whey protein isolate (WPI) in a thermoplastic material (WPIT) with the addition of the antioxidant α-tocopherol, as known as vitamin E, and the plasticizer polyethylene glycol (PEG). The miscibility of the components was evaluated using the Flory-Huggins interaction parameters. WPIT samples were formulated following a Design of Experiments (DOE) factorial design 2² with a central point with vitamin E and PEG content as factors. Samples were prepared using a heat treatment for denaturation, dried in a vacuum oven, lyophilized, and cryogenically milled. The final properties obtained were evaluated by Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), Thermogravimetry (TGA), and moisture content. The results showed miscibility between PEG and WPI and partial miscibility between the pairs α-tocopherol/WPI and PEG/α-tocopherol. PEG and vitamin E exhibited a plasticizing effect on the polymer chains, reducing the contribution of extended β-sheet structures in the secondary structure of the protein, increasing the presence of α-helices, and decreasing the glass transition temperatures related to the protein. Vitamin E improved the thermal stability of WPIT, but its excess may lead to a pro-degradant effect. The amount of α -tocopherol and PEG influenced the moisture content. The hydrophobicity of vitamin E strongly influenced moisture content, keeping it low for samples with higher content of this additive.

Lignin, a renewable biopolymer sourced from plant cell walls, is gaining attention due to its extensive availability from natural resources, native functional groups, low cost, and biodegradability in various applications. In recent years, lignin and its derivatives have been utilized as adsorbents, flocculants, and sterilants in a broad range of applications, including wastewater treatment and sustainable packaging. The growing global demand for clean water—driven by rapid industrialization, urban expansion, and agricultural intensification—has made effective wastewater treatment a pressing environmental priority. In this effort, a dual-functionalization strategy to transform raw lignin into a high-performance adsorbent for the removal of hazardous anionic dyes from wastewater was attempted. Through sequential phenolation and amination via a Mannich reaction—enhancing phenolic hydroxyl groups and introducing nitrogen-rich amine functionalities, respectively—aminated phenolated lignin (Am-PL) was synthesized with nitrogen contents up to 9.6 at%. After each modification, chemical, thermal, and morphological properties of lignin were analyzed. Adsorption capacity and kinetics of Am-PL were investigated for two anionic dyes, Congo red (CR) and methyl orange (MO), as a function of pH and contact time. Am-PL exhibited strong affinity toward CR and MO, achieving maximum adsorption capacities of ca. 53 mg.g^− 1 and 18 mg.g^− 1, with removal efficiencies of 96% and 81%, respectively, under alkaline conditions after 96 h. Am-PL followed pseudo-second-order adsorption kinetics for both aqueous dyes examined. This study demonstrates a green and scalable route to valorize lignin into a next-generation bio-adsorbent, offering a promising solution for sustainable wastewater remediation.

The efficient synthesis of bio-based anionic flocculants is crucial for sustainable wastewater treatment. However, existing bio-based flocculants often compromise between performance and eco-friendliness. This study developed a one-step method to synthesize low degree substitution citrated starch-grafted polyacrylamide (St-CA-PAM) as an eco-friendly alternative to synthetic flocculants. Citrated starch (St-CA) was prepared by esterification with citric acid, achieving a low degree of substitution (DS = 0.061), optimized for solubility and graft polymerization. The polyacrylamide grafting onto St-CA was also confirmed by Fourier Transform Infrared Spectroscopy (FTIR), Proton Nuclear Magnetic Resonance (¹H NMR), zeta potential (ZP), and intrinsic viscosity measurement. The presence of representative peaks in the ¹H NMR and FTIR spectra, indicating amide and carboxylic groups, confirmed the successful simultaneous modification, supported by the viscosity increase from 0.80 dl/g (St-CA) to 1.18 dl/g (St-CA-PAM). St-CA-PAM exhibited superior flocculation efficiency, achieving 90% turbidity removal (< 20 Nephelometric Turbidity Units (NTU)) at 10 ppm, significantly outperforming St, St-CA, and St-PAM, with optimal clarification (98%, 2.42 NTU) under alkaline conditions. The flocculation mechanism involved electrostatic patch effects and polymer bridging, forming large flocs (~ 850 nm) and enhancing sedimentation. Given its bio-based composition, low dosage requirements, and anionic nature, St-CA-PAM presents a promising, scalable, and sustainable alternative for wastewater treatment.

In this study, we propose a facile and efficient approach to fabricate a biocomposite of Ficus carica fruit (FCF) extract incorporated into blue crab shells derived nanohydroxyapatite (nHAp) and marine fish collagen (COL) biocomposite for improved biomedical applications. The rod-shaped nHAp with an average particle size of 88.3 nm was synthesized via a thermal calcination technique. The FCF extract, known for its antibacterial, antioxidant, and anticancer activities, was incorporated into the nHAp matrix. The marine fish collagen acts as a biopolymer that can synthesise materials with flexible properties such as the biodegradability, biocompatibility, renewability, affordability and availability, all are vital for designing effective biocomposite. The characterization techniques including the DLS, FTIR, XRD, TGA, FESEM-EDX mapping confirmed the structural and compositional properties. The FESEM showed agglomerated rod-like nHAp particles, while biocomposite exhibited a more uniform and refined morphology. AFM analysis showed that nHAp/FCF/COL exhibited the smoothest and most uniform surface, indicating enhanced compatibility for cell attachment. The contact angle measurements showed an improved hydrophilicity, decreasing from 32.0° to 15.4°, and also showed the increased water absorption slightly from 10.6 to 26% after 48 h, indicating an enhanced hydrophilicity of the biocomposite. The enzymatic degradation also increased significantly in the biocomposite, reaching 46.2% over 14 days, when compared to 14.8% in the pure nHAp. The zeta potential ranged from − 16.7 mV to − 18.4 mV, showing a good surface charge stability. The Antibacterial testing revealed the maximum inhibition zones of 17 mm (Escherichia coli) and 15 mm (Klebsiella pneumoniae). The in vitro anticancer activity against MG63 osteosarcoma cells portrayed the dose-dependent inhibition, with 79.5% cell death at 200 µg/mL. The AO/EB staining confirmed apoptosis at the concentrations of 25–100 µg/mL. However, the results conclude that the nHAp/FCF/COL biocomposite exhibits an improved physicochemical, antibacterial, anticancer, degradability, hydrophilicity, and biocompatibility properties which makes it as a promising material for various biomedical applications.

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This study presents a sustainable approach for the extraction and functionalization of lignin from hemp biomass using choline chloride-based deep eutectic solvents (DES), formulated with hydrogen-bond donors such as lactic acid, ethylene glycol, and urea. Lignin was successfully extracted with a yield of 10.34% and subsequently converted into nanoparticles via anti-solvent precipitation and mechanical homogenization. To enhance adsorption performance, the nanolignin was chemically aminated using diethylenetriamine (DETA), introducing amine groups (-NH₂) that facilitate copper ion (Cu²⁺) binding through chelation and electrostatic interactions. Fourier Transform Infrared Spectroscopy (FTIR) confirmed successful amine functionalization with a characteristic peak at 1662 cm⁻¹. Field Emission Scanning Electron Microscopy (FE-SEM) revealed that the nanoparticles had an average size of approximately 50 nm. After amination, Dynamic Light Scattering (DLS) analysis showed an increase in particle size to around 280 nm following amination. Thermogravimetric analysis (TGA) indicated reduced thermal stability, which is consistent with the increased surface area observed in Brunauer-Emmett-Teller (BET) analysis (39.39 ± 0.18 m²/g). The aminated nanolignin exhibited a high copper adsorption capacity of 141.56 ± 0.72 mg/g. Copper was selected as the model contaminant due to its widespread presence in industrial wastewater, particularly from mining, electroplating, and electronics. In addition to its adsorption performance, the aminated nanolignin demonstrated strong UV absorption and achieved 99.99% antibacterial activity against Staphylococcus aureus (S. aureus), supporting its potential use in integrated UV-shielding and antibacterial applications. These results highlight the promise of aminated hemp-derived nanolignin as a renewable, cost-effective, and multifunctional nanomaterial for advanced wastewater treatment targeting heavy metal and pathogenic contaminants.

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