Journal of Polymers and the Environment最新文献

Erythritol is a sweetener polyol widely distributed in nature. Its industrial production is based on biotechnological fermentative processes using yeasts. It is used essentially in nutrition and pharmaceutical fields. However, due to its still high price, the use of erythritol is not widespread and is lower than that of other polyols. The use of erythritol for polymer synthesis remains largely unexplored by the scientific community. This work describes the synthesis and characterization of polyester, poly (erythritol sebacate) (PES), obtained by thermal polycondensation of erythritol and sebacic acid in a two steps approach. A prepolymerization step was realized at different temperatures (150 °C, 160 °C and 170 °C, respectively) followed by a cure step at 150 °C. It was found that using a higher temperature allows the same degree of polymerization (50%) to be achieved in a shorter period, but this leads to prepolymers with a more heterogeneous oligomeric composition. This is reflected in the final properties of the polymers after curing. Synthesis at 150 °C produced a polymer with superior mechanical performance (ultimate tensile strength: 0.5 MPa; Young’s modulus: 0.44 MPa: elongation at break: 123%) and higher chemical resistance to solvents than polymers synthesized at 160 °C and 170 °C. The glass transition temperature (T_g) is between − 20 and 0 °C for all polymers and density is 1.08 g/cm³. Based on these results, we believe that PES is a good elastomer with tunable properties and potential for selective absorption of molecules, such as ethanol, that could be useful for beverage industry and biotechnological applications.

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Cellulose is a versatile material that can be modified to possess stable and long-lasting antibacterial and antioxidant properties. Herein, we synthesized CELL-GA graft copolymers by grafting gallic acid (GA), a natural antibacterial agent, onto microcrystalline cellulose (MCC) using an indirect esterification method. The grafting rate achieved was 26.8 mg/g. The products were characterized at various stages using FTIR and ¹H NMR spectroscopic methods to validate the synthesis mechanism of CELL-GA. The antioxidant activity of the products was evaluated by measuring the scavenging rate of various free radicals and the reduction rate of Fe³⁺. It was observed that the antioxidant activity of CELL-GA increased with the higher GA grafting rate. The antibacterial capacity of CELL-GA was found to increase with its concentration through the plate counting method. The antibacterial mechanism of CELL-GA was explored by assessing ATPase activity and the extent of damage to the cell membrane. Our findings indicate that CELL-GA is a cellulose-based antibacterial material synthesized with natural antibacterial agents and MCC, is safe and non-toxic. It exhibits good biocompatibility, stable antioxidant properties, and antibacterial effects, expanding the potential applications of cellulose and offering a novel approach to creating natural biomass-based antibacterial materials.

Bacterial cellulose (BC) is a sustainable material renowned for its three-dimensional nanofibrous structure, offering diverse applications in medical, textile, leather, and other industries. However, developing effective modification technologies for BC has presented contemporary challenges regarding sustainability and efficiency, both in academia and industry, with electron beam irradiation (EBI) emerging as a promising, fast, scalable, and sustainable solution. This study focuses on leveraging EBI-induced decomposition on hydrated BC nanofibrous networks to generate an aerogel-like surface morphology post-dehydration, offering a chemical-free modification method. Investigating the effects of EBI across various absorbed doses (0, 10, 50, and 100 kGy) on BC properties aims to lay the groundwork for employing EBI in BC modifications. Successful fabrication of BC with aerogel-like surface morphology at an absorbed dose of 50 kGy resulted in fascinating findings in terms of applications, including decreased tensile strength (7.7 ± 1.3 MPa), increased bending modulus (6062.7 ± 1574.8 MPa), partially reduced thermal stability (primary peak at approximately 320 ± 4 °C and a new secondary peak at approximately 238 ± 5 °C), slightly decreased crystalline index (79.3 ± 1.0%), decreased moisture regain (5.6 ± 0.9%), and notably enhanced thermal insulation (reduced maximum heat flux of 0.057 ± 0.004 W/cm²). Additionally, EBI treatment induced oxidation, slightly increasing oxygen content and causing a yellowing effect on BC while preserving most functional groups and the hydrophilicity of BC. The adoption of EBI provides a premise for future studies and applications in BC functionalization, utilizing advanced and sustainable technology for mass production and sustainable applications of BC-based products.

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Nowadays, thermoset polymers stand out as notable composites, but the surge in global thermoplastic production has raised concerns due to the non-recyclability of these composites, leading to an increase in landfill waste. In response to these challenges, researchers are investigating innovative approaches to enhance thermosetting materials, focusing on the modification of crosslinking agents responsible for forming a covalently bonded network. Vitrimers offer a promising solution by enabling re-processability while maintaining favourable thermo mechanical properties and solvent resistance. Although many current vitrimers use synthetic polymeric molecules from fossil-based sources, there is a growing interest in bio-based vitrimers. While still in early development, these bio-based alternatives leverage biomass for creating durable polymers, aligning with the goal of establishing a circular economy. This review has been designed to highlight the use of covalently modified networks to produce advanced synthetic and bio-based vitrimer composites with diverse applications, contributing to the development of sustainable materials for the next generation through the use of recyclable resources and renewable feedstocks in polymer network synthesis. This review also explores vitrimers, examining their unique characteristics and addressing current limitations hindering their widespread adoption as recyclable materials with superior performance.

Water contamination from organic pollutants like dyes is a major environmental issue. The current study focused on the synthesis and use of a novel polymeric adsorbent from fully bio-based raw materials. UV curing, an eco-friendly synthesis process, was applied to achieve it. The polymer was then analyzed utilizing various techniques. The dye adsorption capacity of the adsorbent was measured by methyl violet removal, a dangerous organic water pollutant. The study also tested how temperature, pH, initial methyl violet concentrations, and contact time affect MV adsorptive clearance. The study examined kinetics using pseudo-first-order, pseudo-second-order, and intraparticle-diffusion models in which the pseudo-second-order model is the best mechanism. This adsorbent was tested for methyl violet dye removal. The maximum adsorption capacity was observed at 200 mg/L starting concentration, 298 K to 328 K temperature range, 30 min contact time (t), and 3 g/L adsorbent concentration. The comparable adsorption capacities were 58.82 mg/g, 60.97 mg/g, 61.34 mg/g, and 62.89 mg/g at 298 K, 308 K, 318 K, and 328 K, respectively. After examining several isotherm models, the Freundlich model was chosen. This model better describes spontaneous adsorption than the Langmuir, Tempkin, and Elovich models. MV adsorption is spontaneous and endothermic, according to thermodynamic studies. The bio-based polymer’s extensive examination shows its promise for water filtering.

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Nowadays, pH-sensitive and controlled drug delivery systems are urgently required in targeted cancer therapy to increase the drug efficacy and reduce the side effects of cytotoxic drugs. Hence, the present research describes the preparation of Mg-Al-Ca layered double hydroxide (LDH@Fe₃O₄) coated with polyethylene glycol (PEG)/doxorubicin (DOX)/curcumin (CUR) for targeted and controlled delivery of DOX and CUR (LDH@Fe₃O₄-PEG-DOX-CUR) to liver cancer treatment. The prepared nanocarriers were characterized by FT-IR, FE-SEM, EDX, XRD, BET, VSM, and Zeta potential. The in vitro release investigations of DOX and CUR from the PEG-DOX-CUR and LDH@Fe₃O₄-PEG-DOX-CUR confirmed a pH-dependent behavior. The release of drugs from these systems follows the Korsmeyer-Peppas kinetics model. In addition, the LDH@Fe₃O₄ demonstrated low cytotoxicity and good biocompatibility, as confirmed by in vitro cytotoxicity and DAPI tests against L929 (non-cancerous cells) and HepG2 (human liver cancer cells) cell lines. Whereas, the PEG-DOX-CUR and LDH@Fe₃O₄-PEG-DOX-CUR showed higher cytotoxicity effects against HepG2 cells due to targeted co-delivery of DOX and CUR. Based on the findings, the developed nanocarriers have the potential to be utilized as targeted co-drug delivery systems in biomedical applications.

The effect of the sequence to add dicumyl peroxide (DCP) to the polylactic acid (PLA) and epoxidized natural rubber (ENR) blending was investigated. According to the tensile and impact resistance tests, premixing DCP with ENR resulted in blends with better mechanical properties where nearly 20 times improvement of impact strength was observed at 30wt% ENR. In addition, the chemical, morphological, and thermal properties of PLA/ENR blends were investigated via Fourier-transform infrared spectroscopy, scanning electron microscopy, and differential scanning calorimetry analysis, respectively. When DCP is premixed with ENR, DCP could act more effectively as a vulcanizing agent than a compatibilizer, whereas the DCP mixing with PLA/ENR blending of PLA/ENR might lead to more PLA chain scission than DCP premixing with ENR. This study indicated that the toughening of PLA/ENR blends can be significantly enhanced when high ENR vulcanization together with the formation of small PLA phases.

Polymeric nanoparticles possess the benefits of biocompatibility and stability, and also enable the controlled release of drugs. The matrix of the nanoparticle highlights the potential for an enhancement in the stability and efficacy of encapsulated therapeutic enzymes. The oral administration of lipid-polymer nanoparticle significantly improves mucus penetration, cellular uptake, and intracellular transport. The objective of this study is to develop a highly effective lipid-polymer nanoparticle system that is capable of absorbing Papain in the intestine. Papain loaded PLGA nanoparticles and Papain loaded PLGA-phosphatidylcholine nanoparticles were identified using FTIR analysis. Drug encapsulation efficiency of Papain loaded PLGA nanoparticles was found to be 49.20% and Papain loaded PLGA-Phosphatidylcholine nanoparticles was 77.5%. The drug loading capacity was found to be 3.75% and 6.84% for the Papain loaded PLGA- nanoparticles and Papain loaded PLGA-Phosphatidylcholine nanoparticles respectively. The antibacterial activity of Papain loaded PLGA-PC nanoparticles was found to be higher as compared to PLGA-PC nanoparticle for Staphylococcus aureus and Escherichia coli respectively. About 98% viability was observed in RAW 264.7 macrophage cells treated with the maximum concentration of 100 µg/ml of Papain-loaded PLGA-PC nanoparticles thereby depicting the biocompatibility property of the nanoparticles.

ZIF-8 (Zn, Fe) bimetal–organic framework (BMOF) is used for encapsulation of the doxorubicin (DOX). The BMOF surface is coated by chitosan-grafted- polycaprolactone (Cs-g-PCL) to obtain a pH-sensitive nanocarrier. Curcumin (Cur) was loaded into the Cs-g-PCL, and the surface of nanoparticles coated by transactivating transcriptional factor (TAT) peptide. The capability of TAT peptide-coated Cs-g-PCL/Cur/BMOF/DOX was investigated for lung cancer treatment. More than 95% DOX release from Cs-g-PCL/Cur/BMOF/DOX and TAT peptide-coated Cs-g-PCL/Cur/BMOF/DOX under pH values of 5.5 & 6.8 & 7.4 occurred within 72 ± 0.25 & 120 ± 0.3 & 144 ± 0.3 h and 96 ± 0.2 & 144 ± 0.3 & 168 ± 0.5 h, respectively. MTT assay results indicated that the co-delivery of DOX and Cur resulted in decreasing the cell viability of A549 lung cancer cell up to 22.7 ± 0.2%, and the maximum A549 cancer cells death percentage was 93.5 ± 0.1% using TAT peptide-coated Cs-g-PCL/Cur/BMOF/DOX BMOFs. The flowcytometry and confocal images results demonstrated the synergistic effect of TAT peptide and DOX-Cur anticancer drugs on the apoptosis of A549 cancer cells. The in vivo results indicated the maximum tumor inhibition (relative tumor volume: 0.25 after 20 days) for the tumor-bearing mice treated with TAT peptide-coated Cs-g-PCL/Cur/ZIF-8 (Zn, Fe) /DOX BMOF. Overall, results revealed that the co-delivery of anticancer agents and peptides increase the therapeutic efficacy.

Pioneering results of seed-potato health improvement and the suppression of soil-borne infection during the potato production by the preplant coating of tubers with an azoxystrobin-loaded degradable polymer film coating are presented. The film coating was applied to the surface of potato tubers by spraying with a 1% solution of the degradable polymer poly(3-hydroxybutyrate) in dichloromethane mixed with azoxystrobin. The film coating did not damage the tubers or reduce germination. The half-life of the polymer coating in field soil was 25 days. The film degraded gradually from potato planting to the beginning of flowering, ensuring long-term delivery of the fungicide to the plants. In the experimental group, a more effective reduction in the total number of rhizospheric soil fungi, including plant pathogens Alternaria alternata and Fusarium oxysporum, was revealed, compared with the preplant treatment of tubers with the commercial fungicide azoxystrobin (comparison group). The healing effect of the fungicide-loaded coating led to an improvement in the quality of the potato crop. In the experimental group, the total yield and the share of marketable tubers exceeded those of the comparison group by 5.6 t/ha and 8%, respectively. The proportion of Fusarium infected tubers was 8.5% in the experimental group versus 12.1% in the comparison group. The fungicidal effect of a long-term degradable polymer film coating with azoxystrobin was more successful than traditional treatment of tubers with a solution of this fungicide. Thus, the proposed approach is promising for the protection of seed potatoes.

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