Journal of Polymers and the Environment最新文献

Biopolyesters such as poly(butylene succinate) (PBS) show great potential to be used as biobased alternatives to conventional petroleum-based polyolefins. To access technical applications, biobased materials are mostly stabilized using conventional additives, which impair their biobased character. Wine grape pomace (WP), a largely unused, low-value by-product of winemaking, shows great potential to improve the thermo-oxidative stability. Since WP is a natural material, annual variations must be considered for its use as stabilizing bio-filler on an industrial scale. This study investigates the impact of annual variations of WP on the stabilizing effects in PBS. WP of two different varieties and three vintages were studied. The composition and properties of the native by-products were analyzed, and WP-based functional fillers were prepared by industrial mill-drying. The bio-fillers obtained were analyzed regarding their physical, thermal, biochemical, and antioxidant properties and blended into PBS with filler contents up to 20 wt.-% by twin-screw extrusion. The biocomposites’ thermal and thermo-oxidative properties were investigated subsequently. All WP varieties and vintages increased the thermo-oxidative stability of PBS by at least 24% at a filler content of 3 wt.-%, demonstrating the potential of WP as a reliable stabilizer. However, the maximum stabilization effect achieved varied slightly. The results of this study showed that minor differences in the bio-filler properties can be related to meteorological data, while the antioxidant activity, pH, and fat content could be used as bioanalytical indicators to evaluate the thermo-oxidative stabilization effects of WP-based functional fillers to enable reliable industrial applications of WP as a polymer stabilizer.

With rising concerns about antibiotic resistance globally, exploring innovative antibacterial strategies is vital for public health. This work aimed innovatively to improve the biological efficacy of pectin (Pec) hydrogel beads by synergistically utilizing an antibacterial zeolitic imidazolate metal-organic framework (ZIF-8) and tetracycline (TC). ZIF-8 was incorporated at various concentrations within the hydrogel matrix to end this using an in-situ synthesis technique. TC was also pre-loaded into Pec hydrogel beads to further improve their antibacterial features. The application of diverse analysis techniques validated the successful fabrication of nanocomposites. In-vitro Zn²⁺ and TC release were considered by simulating the human digestive system, indicating a sustained and controlled release rate during 8 h (pH 1.2:6.8:7.4 = 20%:20%:60%). Antibacterial tests displayed inhibition zones of 14 ± 0.5 mm and 12 ± 0.5 mm against Escherichia coli and Staphylococcus aureus bacteria. Additionally, the MTT assay displayed potent cytotoxicity (> 70% cell viability after 48 h) for the human colon adenocarcinoma HT29 cell line. These results suggest that the developed nanocomposites have promising potential as an antibacterial bio-platform that is effective against resistant pathogens commonly found in the gastrointestinal tract.

Sodium alginate (SA) hydrogel microspheres are attracting interest in biomedical applications due to their easy degradation and non-toxic nature. However, their high swelling capacity and limited loading efficiency for hydrophobic drugs hinder their application in controlled drug release. The objective of the work is to develop smart vehicles that show effective loading and controlled release of hydrophobic drug. In this study, a series of tragacanth gum/β-cyclodextrin/sodium alginate (TG/β-CD/SA) hydrogel microspheres were designed via the ionotropic gelation method for delivery of hydrophobic drug aspirin. The effect of variation in TG, SA, and β-CD concentration on hydrogel microspheres swelling (%) was examined. The hydrogel microspheres were analyzed using Powder X-ray Diffraction (PXRD), Attenuated Total Reflection-Fourier Transform Infrared spectroscopy (ATR-FTIR), and Scanning Electron Microscopy (SEM) techniques. ATR-FTIR confirmed the successful synthesis of crosslinked TG/β-CD/SA hydrogel microspheres. PXRD showed that the microspheres are amorphous and that the drug is uniformly dispersed within the hydrogel. SEM revealed that the polymeric network has a porous and spherical surface morphology. The drug loading (%), sol–gel fraction (%), degradation (%), and rheological studies were investigated. The in vitro analysis shows a controlled release pattern at pH 1.2 and 7.4 in the TG/β-CD/SA hydrogel. The rheological analysis revealed that the elastic nature is dominant over the viscous one (G’ > G”) in synthesized TG/β-CD/SA hydrogel microspheres. The cytotoxicity evaluations conducted on the HCT-116 cell line indicate the excellent biocompatibility (87.9%) of the hydrogel. The degradation profile of the hydrogel microsphere in pH 7.4 demonstrates complete degradation (100%). Hence, the TG/β-CD/SA hydrogel microsphere reflects its potential as a non-toxic, degradable, and pH-dependent drug delivery system.

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This review delves into the physio-chemical modeling of widely used (bio)degradable polymers such as polylactide (PLA), polyglycolide (PGA), and polycaprolactone (PCL), emphasizing the interplay between environmental conditions, chemical reactions, and material alterations. It utilizes structural equations and reaction–diffusion approaches to model changing structural properties during degradation. This review explores recent advances in physio-chemical modeling techniques, offering insights into predicting degradation kinetics, molecular weight evolution, and mass loss. This comprehensive understanding is essential for tailoring the degradation profiles of (bio)degradable polymers, optimizing their performance, and reducing environmental impact. Additionally, the review covers various other modeling approaches, including the multiscale method and the hybrid method, providing a holistic view of the current state of (bio)degradable polymer degradation modeling.

Cost-effective methods for producing Polyhydroxybutyrate (PHB) can make large-scale bioplastic manufacturing economically viable. This study aimed to optimize PHB synthesis using sugarcane bagasse, a renewable and inexpensive raw material, promoting sustainability by reducing waste and minimizing reliance on non-renewable resources. Soil organisms capable of PHB production were identified using Sudan Black B staining, and Brevibacterium sp. (PP989436) was selected for further study. The production process was optimized using Response Surface Methodology (RSM) and Central Composite Design (CCD) with the statistical analysis showing a significant effect of the optimized medium on PHB production (F-value: 5.17, p-value: <0.005) significantly enhancing PHB yield compared to an unoptimized medium. The optimized conditions resulted in a PHB yield of 7.4 g/L from 12.2 g/L dry biomass (60.65%). PHB characterization was performed using FTIR, NMR, and TGA, and a PHB film was synthesized for evaluation. No cytotoxic effects were observed in MTT and Brine Shrimp Lethality assays. This optimized, sustainable production process presents significant potential for industrial-scale applications, offering an environmentally friendly alternative to petroleum-based plastics.

Polylactic acid (PLA) is a widely used biodegradable polymer, but its brittleness severely limits its further application. This study explores the preparation of anisotropic polylactic acid/thermoplastic polyurethane (PLA/TPU) foam through melt blending with elastomers, rolling, and supercritical fluid foaming (SCF), which substantially enhances the toughness of PLA. Results indicate that the crystallinity and elongation at break of PLA/TPU blend improve with increasing rolling temperature and rolling rate. Notably, at a rolling temperature and a rolling rate of 50%, the elongation at break for the PLA/TPU blends increases from 4.0 to 59.0%. In addition, SCF processing yields an anisotropic, highly oriented, and elongated cell structure within PLA/TPU foam. This cellular architecture further elevates the elongation at break of the rolled PLA/TPU blend to 76.8% and 1820.0%. This research offers a straightforward, environmentally friendly, and scalable method for fabricating high-strength PLA-based foam materials, equipping them with functionalities such as buffering, sound absorption, shock absorption, heat preservation, etc., which is suitable for electronics, home appliances, sports and other fields.

In the present study, the ZnO nanoparticle surface is coated with lignosulfonate (ZnO-lignin) via a novel in-situ method using industrial lignosulfonate as raw materials to obtain a hydrophilic nanomaterial for incorporation into the polyamide layer of a thin-film nanocomposite (TFN) forward osmosis membrane through interfacial polymerization. Incorporation of hydrophilic ZnO-lignin into the polyamide layer induces the formation of nanochannels around the nanoparticles since water molecules absorbed on hydrophilic nanoparticles can terminate the interfacial polymerization by hydrolysis of trimesoyl chloride monomers. In addition, ZnO-lignin significantly impacts the polyamide layer’s properties in the modified TFN membranes, which had measurably more hydrophilic, thinner and smoother surfaces than the bare thin film composite (TFC) membrane. The covalent bonding of hydroxyl groups with trimesoyl chloride enables the synthesis of a thin polyamide film with high stability and improved performance. At the same time, the sulfonic groups endive membrane surfaces with a negative charge, hence immensely enhancing the membrane selectivity toward NaCl and heavy metal ions. These changes in the properties of the polyamide layer are nearly twice the water flux and raise the selectivity for the optimal membrane. With the assistance of 400 ppm of ZnO-lignin, the water flux of the TFN-ZLS.2 membranes were augmented up to 22.5 LMH, corresponding to 95% of the water flux enhancement compared to the control TFC membrane. In addition, the TFN-ZLS.2 membrane presented higher rejection toward Cr⁺³ and Cu⁺² than control TFC membranes, verifying enhancement of the selectivity of the polyamide layer by incorporating ZnO-lignin. Our results indicate that hydrophilic shells in ZnO-lignin nanoparticles significantly develop TFN membranes with high separation performance.

The use of waste cooking oil (WVOs) for technological applications is a required alternative that contributes to the principles of the circular economy and demands of replacement of fossil sources. This work explores the epoxidation of residual soybean oil (RSO) from frying and investigates the crosslinking of residual epoxidized soybean oil (RESO) in contrast to the crosslinking of virgin epoxidized soybean oil (ESO), using fumaric acid (FMA). The curing and degradation kinetics of RESO/FMA and ESO/FMA compounds were investigated for molar ratios 1:0.45 and 1:0.70. RESO/FMA composites showed higher curing activation energies (E_ac) during crosslinking, and higher degradation activation energies (E_ad) given the greater thermal stability, been able to replace virgin ESO in epoxy resins.

Extrusion-based 3D printing stands out as one of the most widespread additive manufacturing techniques, finding applications across engineering and medical sectors, primarily owing to its use of thermoplastic polymers. While poly(lactic acid) (PLA) remains among the most widely used bio-based compostable polymers in material extrusion, its inherent brittleness imposes limitations in sectors requiring more flexible and ductile materials. In this context, the combination of PLA with poly(butylene adipate-co-terephthalate) (PBAT) results in more flexible compostable blends, broadening the scope of advanced applications of 3D-printed parts while upholding sustainability standards. Despite the considerable potential of PLA/PBAT blends, research on their use in material extrusion 3D printing remains limited, highlighting an opportunity for significant advancements in the near future. Therefore, this article provides a detailed review of the influence of printing parameters on the properties of 3D-printed PLA/PBAT blends. It begins with a brief overview of the synthesis methods of PLA and PBAT, and their blend compatibilization strategies, showcasing advancements in the pursuit of versatile and sustainable materials. Furthermore, it also examines potential applications while identifying research gaps that can steer future investigations. In essence, this review not only provides valuable insights for optimizing the printing parameters of these blends in extrusion-based 3D printing but also contributes to the development of more adaptable and sustainable materials, holding substantial promise across various technological domains.

Targeting crucial pathways in cancer cells with combination drugs becomes vital as treatment resistance is reduced and the drug’s efficacy improves even at low doses. Bortezomib (BTZ) and vincristine (VCR) are chemotherapy drugs provided to individuals with solid tumors. This work suggests encapsulating BTZ and VCR in chitosan (CS) nanoparticles (CSNPs@BTZ-VCR) grafted polymers to combat cancer. To enhance the solubility of CSNPs further cross-linked with polyethylene glycol (PEG) (PEG/CSNPs@BTZ-VCR). Several methods were used to examine the NPs. SEM images showed nanoparticle fabrication, drug loading into CSNPs, and PEG cross-linking. The studies were developed to assess the synergic effects of the drugs in NPs against NCI-H661, NCI-H460, A549, H157, and H1299 lung cancer cells. The PEG/CSNPs@BTZ-VCR NPs were found to synergistically reduce the cell survival of the NCI-H661, NCI-H460, A549, H157, and H1299 cell lines, with a combined result of 0.313. The synergic effect of the BTZ and VCR was considerably more potent, with 0.22 of PEG/CSNPs@BTZ-VCR NPs. In addition, PEG/CSNPs@BTZ-VCR NPs have a higher DPPH scavenging activity (58.32%) than drug-alone. The synergistic efficiency of the PEG/CSNPs@BTZ-VCR NPs triggers apoptosis variations was detected using Calcein AM/Propidium Iodide (PI), DAPI, and PI biochemical staining techniques. Further, the apoptosis mechanism was confirmed by FITC/Annexin-V and PI staining methods. Outcomes showed that the co-delivery of bortezomib and vincristine-loaded chitosan cross-linked polymeric nanoparticles was much higher in lung cancer cells when related to free drugs.