Journal of Polymers and the Environment最新文献

This research presents an innovative strategy for the design and synthesis of a cross-linked hydrogel polymer matrix based on lignin-chitosan biopolymers (Lig-CS), which is utilized to encapsulate silver nanoparticles, forming a distinctive bio-nanocomposite. The hydrogel structure of Lig-CS was developed through hydrogen bonding and further cross-linked with glutaraldehyde, creating a natural framework that acts as a stabilizing, reducing, and stabilizing agent for the incorporation of silver nanoparticles (Lig-CS/Ag NPs) under ultrasonic irradiation. Various advanced techniques, including UV–vis, FE-SEM, TEM, EDX, FT-IR, ICP-OES, TGA, and XRD confirmed the well synthesis of the Lig-CS/Ag NPs composite. TEM analysis indicated that the silver nanoparticles were spherical, uniformly distributed, and approximately 10–15 nm in size. Additionally, the catalytic efficiency of Lig-CS/Ag NPs was assessed in reducing nitroarenes to produce aniline derivatives. The nanocatalyst demonstrated excellent recyclability, retaining its activity after more than nine cycles with only a slight decrease in efficiency. In addition, the Lig-CS/Ag NPs nanocomposite was engaged in biological assays like study of antioxidant properties by DPPH mediated free radical scavenging test and treating the diarrhea in rats. These Lig-CS/Ag NPs nanocomposite exhibited a decrease in the inflammatory cells infiltration in both the colon and ileum. Moreover, they resulted in lower concentrations of TNF-α, IL-17A, IL-6, and IL-1β, while simultaneously increasing the levels of IL-10 and IL-4 in the colon tissues. Additionally, the nanoparticles promoted the propionate and acetate production, modulated the composition and diversity of gut microbiota, enhanced the relative abundance of Bacteroides and Lactobacillus, and reduced the Coprococcus and Blautia relative abundance. The data reported that Lig-CS/Ag NPs nanocomposite may significantly improve the restoration of intestinal architecture in rats, reduce the levels of inflammatory cytokines, increase concentrations of SCFAs, aid in the recovery of intestinal mucosal barrier and the gut microbiota, and alleviate antibiotic-associated negative efficacies, including diarrhea and microbiota dysbiosis. Our investigation revealed that Lig-CS/Ag NPs nanocomposite has the potential to protect the intestinal barrier by enhancing the Claudin-1 and Occludin expression. Additionally, these nanoparticles were observed to suppress the MAPK inflammatory signaling pathway, which contributes to the amelioration of inflammatory conditions. Upon the conclusion of clinical trial studies, these nanoparticles could represent a new remedial approach for the diarrhea treatment in humans.

A pH/thermo-responsive nanoframeworks has been engineered using ZIF-8 decorated with the chitosan (C)-poly(N-isopropylacrylamide) (C-PNIPAM) for the co-delivery of oxaliplatin (OXP) and cabazitaxel (CTX) in liver cancer cells. The chitosan PNIPAM nanoparticles (CPNPs) exhibited particle diameters of 205 nm and a surface charge of + 28 mV. The CTX and OXP loading contents in the CPNPs were 12.10% and 54.49%. NPs exhibited a pH-and thermo-responsive drug release, characterized by a continuous and extended-release. The anticancer activity demonstrated a notable synergistic effect of OXP@ZIF-8/CTX@CPNPs, resulting in HepG2 and Bel7402 cells IC₅₀ of 2.21 and 5.23 µg/mL. The resultant NPs were lower cytotoxic than OXP and CTX on non-cancerous NIH3T3 cell lines. OXP@ZIF-8/CTX@CPNPs shows enhanced cellular uptake in HepG2 cells. The apoptotic mode of cell death in OXP@ZIF-8/CTX@CPNPs treated cells was indicated by acridine orange/propidium iodide (AO/PI) staining techniques. 4′, 6-diamidino-2-phenylindole (DAPI) staining also confirmed nuclear changes such as fragmentation and condensation. Annexin V-FITC/Propidium iodide (PI) staining with flow cytometry showed that OXP@ZIF-8/CTX@CPNPs improved apoptosis in HepG2 cells. The study validated the superior efficacy of the engineered polymeric drugs integrated with metal-organic nanoframeworks in combinational treatment against liver cancer cell lines, exhibiting reduced adverse effects compared to free anticancer drugs (OXP and CTX).

Plastic materials have long been essential in the production of food packaging, due to their advantageous properties, cost-efficiency, and durability. Nevertheless, alarming reports from the United Nations indicate that Latin America generates 17,000 tons of plastic waste daily, with 30% of it being released into the environment. As a reaction, major companies in the food industry have committed to introduce more environmentally friendly packaging solutions. This research aimed to gather the reported packaging needs of some major Latin American food industries and propose a suitable bioplastic or natural polymer alternative to traditional plastics. Polyethylene Furanoate (Bio-PEF), derived from biomass, is highlighted as the most promising bioplastic. The study outlines a detailed production process for Bio-PEF from sucrose and ethylene, including four stages: obtention of 5-hydroxymethylfurfural, oxidation to furandicarboxylic acid (FDCA), production of ethylene glycol (EG), and polymerization of FDCA and EG. Braskem (Brazil), a pioneering and leading producer of bio-polyethylene (bio-PE), was identified as one of the most potential companies in Latin America to manufacture Bio-PEF. Although, the technology can be applied to any bioethanol company operating under a biorefinery scheme. In the Bio-PE process, Braskem uses sucrose from sugar cane to produce ethylene which could be subsequently used to synthesize Bio-PEF. Braskem is equipped with the necessary technology and scale for Bio-PEF production. Material balances using 10% of the sucrose and ethylene as inputs in a four stages production demonstrated a potential yield of 35.49 kg/h of Bio-PEF, producing 0.31 kg of Bio-PEF/Kg of sucrose.

3D printing has found applications across various sectors, including water treatment, where the incorporation of novel materials enhances sustainability and imparts specific functional properties. This study focused on the production of polymeric filaments for Fused Deposition Modeling (FDM) 3D printing, utilizing a PLA/PBAT blend infused with activated carbon and magnesium oxide, with concentrations up to 6 parts per hundred resin (PHR), for use in water treatment membranes. The distribution, composition, and morphology of the particles were assessed using Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). Alterations in physical properties, including water absorption and contact angle, were observed in comparison to the pure commercial blend. An adsorption efficiency exceeding 60% for methylene blue was achieved, as confirmed by SEM analysis of the membranes. Furthermore, the filaments demonstrated suitability for the production of high-quality water treatment membranes, as evidenced by SEM and Optical Microscopy (OM) analysis.

The depletion of high-grade ore reserves necessitates innovative approaches in mineral processing, particularly for recovering valuable minerals from fine tailings. This study examines the use of bio-based hyperbranched polymers synthesized from carboxymethyl guar gum for selective flocculation of minerals, specifically focusing on kaolinite and iron ore mixtures in wastewater. Traditional coagulants present environmental drawbacks, prompting the exploration of biodegradable alternatives. Hyperbranched polymers possess a unique architecture that may enhance their interaction with suspended particles, potentially improving flocculation efficiency. This research investigates the grafting of carboxymethyl guar gum with Poly (2-methacryloyloxyethyl trimethylammonium chloride), which provides a high charge density and a stable cationic character across a range of pH levels. A kaolinite-iron ore model system was employed to evaluate the selectivity and efficiency of the synthesized flocculants under controlled conditions. Results indicate that hyperbranched carboxymethyl guar gum/Poly(2-methacryloyloxyethyl trimethylammonium chloride) exhibits improved flocculation performance and mineral selectivity compared to traditional flocculants. This study highlights the potential of HBPs as effective and environmentally sustainable alternatives for mineral recovery and wastewater treatment applications.

Graphical abstract

Flexible PLA-based antibacterial composite films were prepared using a natural oil, Liquidambar orientalis, as bio-based plasticizer, and 2D graphitic carbon nitride (g-C₃N₄) decorated with Ag nanoparticles with a particle size of 10–30 nm as antibacterial agent (Ag@g-C₃N₄). This structurally designed antibacterial nanocomposite was synthesized with the preparation of g-C₃N₄ by high-temperature annealing followed by the reduction of silver salt onto g-C₃N₄. The Ag@g-C₃N₄ nanocomposite exhibited a surface area value of 18 g/m². PLA/Ag@g-C₃N₄ composite films were prepared with solution casting method by introducing 30 phr of L. orientalis oil and various amounts (1, 2 and 4 phr) of Ag@g-C₃N₄. It was found that 30 phr of L. orientalis oil successfully plasticized the PLA and reduced its glass transition temperature from 60 °C to 43 °C and its melting temperature more than 10 °C by reducing the strong interactions and hydrogen bonds between PLA chains. L. orientalis oil also acted as a dispersion agent for the Ag@g-C₃N₄ nanocomposite particles and significantly improved their antibacterial activity. Antibacterial tests performed using Gram-positive bacteria (Staphylococcus aureus ATCC 25923) and Gram-negative bacteria (Escherichia coli ATCC 25922 and Acinetobacter baumannii ATCC BAA 747) indicated that introducing a small amount of 2D Ag@g-C₃N₄ nanocomposite particles into PLA yielded superior antibacterial activity.

Developing a biomimetic porous composite scaffold with mechanical properties tailored to meet the requirements of bone defect repair, enhanced bioactivity, and controlled biodegradability is of great significance for effective bone regeneration. In this work, calcium silicate (CS, CaSiO₃) was introduced into polylactic acid (PLA) as an addition. A scaffold model was then constructed using triply periodic minimal surfaces (TPMS), and a PLA/CS composite scaffold was fabricated using selective laser sintering (SLS) technology. Among them, when the CS content was 5wt%, the compressive strength and modulus of the composite scaffold were 4.8 MPa and 52.1 MPa, respectively, which were 104.2% and 43.9% higher than those of the PLA scaffold. The mechanical strengthening can be attributed to the particle reinforcement effect caused by the inherent high stiffness of CS. Additionally, the incorporation of CS accelerates the degradation of the scaffold while enhancing its bioactivity. The composite scaffold also demonstrated favorable cell compatibility in in vitro tests, supporting its potential for biological integration. In summary, the PLA/CS composite scaffold with coordinated regulation of multiple properties is expected to become a potential choice for bone defect repair.

Polyisocyanurate (PIR) foams cannot be processed quickly and efficiently due to their thermophysical properties. To address this challenge, this work investigates the alcoholysis degradation process of waste PIR foams, aiming at the high-value utilization of resources. With respect to the chemical recovery method of polyurethane, the effects of catalyst type, dosage, and ratio on the effect of alcoholysis were investigated. The results showed that the performance of the resulting recycled PIR tubular shells was superior to that of commercially available products when an alcoholysis agent with a butylene glycol to diethylene glycol ratio of 43:57 was used. The mixture was reacted at 180 °C for 2 h, and a combination of 0.100% LaNiO₃ and 0.200% NaOH catalysts was used. The lowest viscosity of degradation product obtained under this scheme was 2201.6 mPa·s, and the thermal conductivity of the regenerated PIR foam was 0.025 W/(m·K) with a compression strength of 239 kPa. This study provides an efficient and feasible process route for the resource utilization of used PIR foams.

Metal-organic frameworks have recently become popular in biomedical applications due to their high surface areas, porosity, suitable mechanical properties, controlled degradability, and selective compositions. Among them, UiO-66 is particularly noteworthy for its exceptional stability, biodegradability, low toxicity, and osteogenic properties. Herein, UiO-66 was synthesized via a solvothermal method and characterized employing FTIR, XRD, FESEM, and TEM analyses. Subsequently, poly-3-hydroxybutyrate-zein/UiO-66 electrospun composite scaffolds were fabricated. Regarding the SEM, mechanical analyses, and water contact angle results, the scaffold containing 2 wt% UiO-66 exhibited the optimum characteristic. EDS and TEM examinations confirmed UiO-66’s presence and distribution, TGA validated its claimed amount in the scaffold, and FTIR revealed the possible interactions between ingredients. Incorporating 2 wt% UiO-66 reduced the fiber diameter and water contact angle by about 54 nm and 20°, respectively, while increasing surface roughness and crystallinity. UiO-66 significantly enhanced ultimate tensile stress and Young’s modulus by approximately 90% and 101%, respectively. It also boosted the biomineralization of the scaffold and hastened the degradation rate. Eventually, adding UiO-66 led to noticeable increases in viability, proliferation, attachment, ALP activity, and ECM mineralization, as well as upregulation of COLΙ, RUNX2, and OCN genes of MG-63 cells seeded on the scaffolds. In conclusion, incorporating UiO-66 not only reinforced the composite scaffold but also stimulated osteogenesis, making it an advantageous candidate for bone tissue engineering applications.

Inflammatory bowel disease (IBD) encompasses a group of chronic inflammatory disorders of the gastrointestinal tract, including Crohn’s disease and Ulcerative colitis. Conventional treatments for IBD often involve systemic administration of corticosteroids, such as Prednisolone (Pred), which can lead to undesirable side effects. Delivery systems are preferred for the administration of drugs, as they enhance the bioavailability of the drug while reducing the dosage and targeting the affected tissue. This leads to effective treatment with minimal side effects. Hydrogels are considered to be one of the effective drug delivery systems as they facilitate site-specific drug delivery. In this study, we aimed to optimize and develop a localized hydrogel-based drug delivery system using agarose (Agr) and alginate (Alg) respectively for targeted drug therapy in IBD. Pred, a potent corticosteroid with anti-inflammatory properties, was incorporated into the optimized hydrogel matrix at various concentrations. The hydrogel exhibited good swelling ability (12–14 g/g) and mucoadhesivity (43.54 ± 2.52%) at lower Agr concentration compared to Alg hydrogel as control. The 1% (w/v) agarose/2% (w/v) alginate hydrogel (A₁AH) was able to encapsulate approximately 97.31 ± 1.77% of Pred and possessed the ability to deliver the drug in a prolonged manner over a sustained time period. The Pred-encapsulated hydrogel (P-A₁AH) system displayed no in vitro cytotoxic effects on HCT116 cell lines and was able to effectively suppress inflammatory mediators like reactive oxygen species (ROS), nitric oxide (NO) and revealed effective wound healing effects. The developed mucoadhesive hydrogel system can be exploited for the delivery of various drugs to target intestinal inflammation for prolonged effects.