Journal of Polymers and the Environment最新文献

Polylactic acid (PLA) fibers have great potentials in textile fields with eco-friendship and low carbon emission. However, the poor ductility, inferior free radical scavenging effect, and moderate biodegradability make them challenging in qualified fibers. In this context, a series of PLA fibers with excellent free radical scavenging effect were prepared by melt spinning with PLA /poly (ethylene oxide) (PEO) /curcumin (CUR). The tenacity and free radical scavenging effect of the fiber with 12.0 wt% PEO and 1.0 wt. % CUR were 3.14 CN dtex^-1, 96.2% respectively, compared with 2.24 CN dtex^-1, 2.9% for pure PLA fibers, respectively. X-ray diffraction analysis showed that CUR behaved as nucleating agents and accelerated the crystallization with elevated crystallinity. The synergistic action of PEO and CUR was found to have significant effects on the mechanical, thermal, crystalline, and free radical scavenging properties for the composite fibers. X-photoelectron spectroscopy analysis, morphological investigation, and disintegrability tests in soil demonstrated the homogenous, ductile, and outstanding biodegradable behaviors of the as-prepared fibers.

There is increasing interest in using green and sustainable materials as replacements for petroleum-based polymeric materials. Plant oils are of particular interest as raw materials for the synthesis of new polymers for different applications. In this work, we have made novel green nanocomposites comprising epoxidized soybean oil (ESO), citric acid (CA), and cellulose nanofibrils (CNF) using supercritical carbon dioxide, without a catalyst or an accelerator. Both polymeric foamed products and bubble-free products could be obtained. The chemical structure of the new products was studied by solid-state and solution-state nuclear magnetic resonance (NMR), together with dynamic mechanical properties and glass transition temperature (T_g). The product was found to contain low-molecular-weight polymers of ESO involving tetrahydrofuran structures in the polymer backbone and ester crosslinks between ESO and CA. The incorporation of nanocellulose was found to increase the T_g and the storage modulus (G’) of the products. The G’ at 25 °C ranged from 0.08 MPa to 0.63 MPa with CNF loading from 0.00 g to 0.24 g. The T_g measured by dynamic measurement ranged from 6.41 °C to 11.07 °C. Effect of CO₂ pressure on the dynamic mechanical properties and T_g showed that the G’ at 25 °C ranged from 0.10 MPa to 0.14 MPa when the pressure changed from 55.2 bar to 75.8 bar, while the T_g changed from 6.70 °C to 7.28 °C under these conditions. With the aids of gel contents, TGA and FTIR results, the formation of crosslinked nanocomposites would be confirmed.

In the present work, a polymeric nanocomposite adsorbent of cross-linked chitosan-adipic acid and SnO₂ nanoparticles (CS-ADP/SnO₂) was created for the adsorption of methyl orange (MO) dye from water. Response surface methodology (RSM) was used to examine how three factors affected the adsorption of the dye MO: time C (10–40 min), pH (4–10), and CS-ADP/SnO₂ dosage (0.02–0.08 g/L). The CS-ADP/SnO₂ nanocomposite has a BET surface area of 28.64 m²/g, a total pore volume of 0.0271 cm³/g, and a mean pore diameter of 3.79 nm. The several XRD diffraction peaks and average crystallite size of 31.33 nm of the CS-ADP/SnO₂ nanocomposite indicate that it primarily possesses polycrystalline properties. The MO adsorption by CS-ADP/SnO₂ could be well described by the isotherm model, which was validated by the adsorption kinetics and Freundlich and pseudo-first-order kinetic models. The best circumstances for maximum MO elimination (80.54%) were found to be a pH of 4, a CS-ADP/SnO₂ dosage of 0.055 g/L, and a contact period of 40 min, according to the results of the BBD model. At 25 ^oC, the maximal adsorption capacity of the CS-ADP/SnO₂ nanocomposite toward the MO dye was 344.91 mg/g. The Yoshida H-bonding, electrostatic interaction, hydrogen bonding, and n-π stacking interaction, were postulated as the mechanisms for MO dye adsorption onto CS-ADP/SnO₂ nanocomposite. In summary, this research suggests that the composite has the ability to effectively remove organic dyes from water systems, making it a promising new adsorbent.

In this paper, the modified lignin drug carrier materials with targeted slow release effect were studied. 0.2 g of alkali lignin was added to 20 mL of acetylation reagent (the ratio of acetyl bromide to acetic acid is 8:92) at 50 °C, sealed and stirred for 3 h for acetylation reaction, rotary evaporation for 30 min, drying to a fixed weight, to obtain acetylated lignin, recorded as ACAL. Dissolve 2.0 mg of ACAL in 10 mL of 99.5% ethanol solution and stir continuously at room temperature for 2 h. Deionized water is added during mixing until the desired water content is reached. After continuous stirring for 10 min, the lignin-coated material was obtained by rotating evaporation for 2 h. 5 mL prepared ACAL solution (6 mg/mL) and 5 mL prepared PTX solution (10 mg/mL) were mixed, and 0.15 V/min was dropped into deionized water magnetic force and stirred for 16 h until the final water content was 99%. The suspension was transferred to a rotary evaporator, evaporated for 2 h, and dried to constant weight to obtain the lignin/paclitaxel drug carrier system, labeled as ACAL/PTX materials. Fourier transform infrared spectroscopy (FIRS), hydrogen nuclear magnetic resonance (¹H-NMR), ultraviolet-visible spectroscopy (UV), field emission scanning electron microscopy (SEM) and Zeta potential were used to study and characterize the modified lignin drug carrier materials with targeted and sustained release. The drug release, toxicity, distribution and anticancer effect in vitro were studied. The results show that the solubility of acetylated lignin in alcohol is 1.14 times that of alkali lignin. he modified acetyl group replaced the free phenol hydroxide group in the benzene ring of lignin, and the structure of lignin itself did not change. Lignin coating material is hollow porous nanospheres, and its drug loading rate and encapsulation rate reach 17.8% and 71.23% respectively. acilitate release rate was only 21.94% when pH value of human gastric juice was 1.2. The release rate of facilitate could reach 74.81% at pH 5.5 of simulated tumor cells. Significant drug release occurred within the first 10 h. When the concentration of lignin carrier material was 10–100 mg/mL, the survival rate of cells was greater than 95%, indicating that lignin coated material was non-toxic and had stable slow-release and targeting effect. In addition, the biological distribution of facilitate in mice showed that PTX was mainly concentrated in tumor sites of mice, but in liver, spleen, lung and kidney was low. In the anti-cancer effect test, the tumor cells were significantly reduced after 5 consecutive administration, which also proved that the lignin/PTX drug delivery system has high targeting and anti-cancer effect.

The development of bio-based polymer blends for optoelectronic applications constitutes a pivotal and sustainable approach in the domain of materials science. In this work, biopolymer films, having a low bandgap and high optical conductivity, have been developed using chitosan and aminated starch, through a casting route. Initially, aminated starch synthesised by reductive amination was subjected to the evaluation of its structural, optical, thermal, and morphological features. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV-visible ), field emission scanning electron microscopy (FE-SEM), contact angle evaluation, mechanical studies, biodegradability evaluation, and thermal examinations were executed to evaluate the functional performance of the blends, duly assisted by computational analysis. FE-SEM confirmed the homogeneity, while XRD indicated the amorphous nature of the blends. Thermogravimetric analysis (TGA) highlighted the increase in thermal stability with an increase in the aminated starch content in the blends. The UV-visible measurements indicated high optical conductivity (7 × 10⁹ S/cm) and increased absorption coefficient (56 mm⁻¹) for an optimized blend with high aminated starch content. The energy band gap has been found to reach 2.3 eV, which makes the system a potential candidate for various optoelectronic applications. Computational analysis based on density functional theory (DFT) has been found to support the experimental observations effectively.

Graphical Abstract

Plastic pollution in the marine environment is a persistent and ubiquitous issue. Biodegradable and compostable plastics may present a positive alternative to traditional non-biodegradable polymers for marine applications such as aquaculture. Mater-Bi (MB) is a starch-based polymer used in compostable films and plastic carrier bags and has been proven to completely biodegrade in a variety of laboratory conditions. However, degradation rates in the natural environment differ from static laboratory tests and depend on the specific physicochemical and environmental conditions of a particular location. This study examined the degradation of Mater-Bi in coastal marine conditions in a flow-through mesocosm system, in comparison to polyhydroxybutyrate (PHB), a well-known biopolymer, and high-density polyethylene (HDPE), a traditional plastic polymer. Mass and area loss were both used as proxies for disintegration across a nine-month time span. Results indicate that both Mater-Bi and polyhydroxybutyrate disintegrate when exposed to shallow water column and sediment conditions, losing on average 25 to 47% of area or mass, whereas high-density polyethylene showed no evidence of degradation. Loss of area and mass of Mater-Bi and polyhydroxybutyrate were especially pronounced, averaging 0.87%/week after 30 weeks of submergence when water temperature increased to 20 °C. The disintegration of biodegradable plastics through microbial action over time and in warmer temperatures likely contributed to these results. Biodegradable plastics such as Mater-Bi may therefore have a lower environmental impact and persist in the marine environment for shorter periods of time than conventional non-biodegradable polymers.

Waste fish oils (WFOs) obtained from the wastes of Sprattus balticus and Scomber scombrus have been investigated as a new substrate for the synthesis of polyhydroxyalkanoates (PHA). WFOs produced by thermal or enzymatic methods had some differences in the ratio of fatty acids and lipid saturation. C. necator B-10,646 bacteria, grown in a laboratory Bio-Flo fermenter with high mass transfer characteristics and a high degree of emulsification of WFO fat, provided high productivity in all variants, superior to other substrates (sugars, glycerol, etc.). The total yield of bacterial biomass and PHA content obtained on WFO from smoked sprat heads by thermal or enzymatic method was 87.4 and 109.7 g/L and 75.6 and 81.0%, respectively, for 30 h of cultivation, which slightly exceeded the results obtained using WFO from fresh mackerel heads. Under studied conditions, bacteria utilized the entire spectrum of fatty acids in WFO lipids including polyenoic and saturated fatty acids. This ensured a high degree of utilization of WFOs by bacteria (92.3–94.7%). The synthesized PHA samples were represented by poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate) with similar degrees of crystallinity, molecular weight and temperature characteristics. The studied WFOs can be recommended as a new and renewable substrate for productive synthesis of PHA.

Typically, traditional rare earth element (REE) extraction processes generate industrial effluents rich in REEs, resulting in significant resource waste and environmental pollution. Hence, there are important practical applications for the preparation of adsorbents with high adsorption efficiency and superior stability for the recovery of REEs. In this work, a poly(6-(N-acetyl-acryloylamino) hexyl hydroxamic acid) (PAAHA) chelating resin was successfully prepared by grafting 6-acetyl amino hexyl hydroxamic acid onto polyacrylic resin (D113). The PAAHA chelating resin was utilized for the removal of La³⁺, Ce³⁺, and Y³⁺, and the maximum uptake capacities determined from the batch adsorption experiments were 2.10, 2.38, and 3.98 mmol/g, respectively, which were 3.09, 3.05, and 9.05 times greater than those of the D113 resin. The results demonstrated that the adsorption process was consistent with the pseudo-second-order kinetic and Langmuir isotherm models, suggesting that monolayer chemisorption was the dominant process. Concurrently, five successive adsorption‒desorption cycles revealed that the PAAHA chelating resin displayed remarkable reproducibility and stability. Notably, the –CONHOH group exhibited a marked affinity for REEs, resulting in the formation of stable five-membered rings via mechanism characterization. In summary, this resin represents a novel strategy for designing adsorbents and shows considerable promise for the remediation of mining tailings containing REEs.

Graphical Abstract

A full-control design can significantly improve drug release and cell proliferation for tissue engineering applications in medicine. The present investigation encompassed a molecular docking study which was performed to investigate the interaction of selected active ligand (coumarin) with the L929 mouse fibroblast cell line protein as the receptor. After that, the coumarin was extracted from the roots of p.ferulacea and its subsequent nanoencapsulation with polycaprolactone, employing the coacervation technique to achieve a narrow distribution of nano particle sizes. Subsequently, the electrospinning technique was utilized to apply a second coating to the nano-encapsulated coumarin. Polyvinyl alcohol and gelatin compounds were used to produce electrospun nanofibrous scaffolds for their similarity to the extracellular matrix (ECM). This coordinated nano platform aimed to assess its effectiveness in regulating drug release, evaluate its biocompatibility, and examine its impact on L929 cell proliferation according to the Lag and Log phases of their growth. In silico analyses demonstrated significant interactions and high binding energy values between the coumarin ligand and essential residues of the L929 mouse fibroblast proteins. The results of the experiments were checked using analyses of ¹H NMR, FTIR, UV, SEM, mechanical properties, DSC, HRTEM, and HPLC. The biological effects and cell proliferation were conducted employing the MTT method (up to 5 days). Notably, no cytotoxicity was detected throughout the assessment. In this way, it is feasible to create a synergistic nano delivery system by delaying the release of the drug into account the timing of distinct cell lines’ development phases.

Global health is in jeopardy by the rising emergence of antibiotic drug resistance in pathogenic bacteria. Methicillin-resistant Staphylococcus aureus (MRSA) is a widespread bacterial infection that causes considerable morbidity and mortality on a global level. Finding promising materials for MRSA continues to prove challenging, and it is essential to quest for new and advanced polymeric therapeutics to effectively treat MRSA infections. Ricinoleic acid, a castor oil extract with an unsaturated omega-9 fatty acid and hydroxy acid has sparked growing interest because of its broad-spectrum antibacterial properties. Herein, ricinoleic acid-based polymer is synthesized to combat multidrug-resistant bacteria and few pathogenic microorganisms. The ricinoleic acid polymer (RAP) exhibited efficient antimicrobial activity against E. coli, P. aeruginosa, C. albicans, S. aureus, and MRSA with a MIC of 1.25 mg/mL, 10 mg/mL, and 0.62 mg/mL, 20 mg/mL and 10 mg/mL, respectively. Time-kill assay revealed that the polymer showed biostatic activity against all the tested pathogens. Cytotoxicity assay revealed the polymer showed 100% biocompatibility even at a higher concentration of 50 µg/mL. Effective antibacterial properties, particularly against MRSA and few pathogenic microbes, and good biocompatibility of RAP make it a promising material in surface coatings and hospital-acquired infections.