Journal of Polymers and the Environment最新文献

Recent European guidelines support the use of recycled and biodegradable packaging for food applications. The approval of such packaging must not alter food’s taste or be harmful to health. In this work, PLA pellets were subjected to a post-consumer contamination procedure, washing process, and mechanical recycling, under common conditions of the recycling industry. HS-SPME-GC-MS and HS-SPME-GC-O-MS methods were used to detect volatile compounds and off-odor profiles. 33 different volatile compounds were identified in all samples. Intentionally added and non-intentionally added substances (IAS and NIAS) were identified, including benzaldehyde, benzyl alcohol, and dimethyl-1,4-dioxane-2,5-dione. The relationship between the formation of different NIAS and the PLA recycling process steps was determined. 14 different odor compounds such as benzyl alcohol, benzaldehyde, nonanal, decanal, dodecanal, 2,3-dimethylnaphthalene and 2,4-di-tert-butylphenol were detected and classified into 4 aroma groups (Toasted, Flower, Green and Chemical). The results obtained are essential for the food safety of recycled plastic material for food contact.

Polymers blending has attracted significant interest in recent years owing to the possibility of synergistic interactions between blended materials which can be impressively beneficial over single substrates. Herein, a Tara gum derivative-(PVA-TG) blend was exploited as stabilizing agent for the synthesis of cyto-compatible PAPBA/(PVA-TG)/Ag, colloidal nanocomposite. Based on the in-situ oxidative polymerization strategy, 3-aminobenzene boronic acid (ABBA), was used for the reduction of silver salt, inside highly hydrophilic (PVA-TG) blend. As a result, AgNPs is formed, while ABBA, is oxidized to its conducting polymer conformation (PAPBA), all within the blended polymers solution. PAPBA/(PVA-TG)/Ag, showed dose-dependent cell viability with IC₅₀ of 3.9 µg/mL against human keratinocytes (HaCaT) cells, based on in vitro MTT assay, which attested to its cyto-compatibility. The material was fully characterized using various analytical equipment and was deployed for the detection of metal ion (Au³⁺ ion) in solution. At the optimal detection conditions, absorbance ratios, (A₅₆₀/A₄₂₉) displayed linearity with Au³⁺ concentrations from 0.10 to 10.0 & 10.0–80.0 µM, with 28.5 nM detection limit (LOD). Further, the mechanistic basis of the detection strategy was proven to be based on galvanic replacement and was applied to Au³⁺ detection/monitoring in environmental samples with reliable precision and accuracy (99.4–102.3%). In all, we have showcased an innovatively contrived synthesis strategy which can be of huge benefit in toxic metal ions monitoring in water samples.

This research shows that cationic polyacrylamide (CPAM) flocculants, widely used in wastewater treatment, are susceptible to degradation when in contact with various metallic surfaces. This is evidenced by the investigation of the evolution of CPAM’s rheological properties during degradation within metallic Couette tools, observing a transition from elastic to viscous behavior. The degradation is clearly evident on various metallic surfaces, while thermoplastic surfaces have significantly less effect on CPAM degradation. Key findings indicate that chemical interactions, rather than mechanical stress, are the primary cause of degradation, and this reaction is activated by temperature. Techniques such as Fourier Transform Infrared spectroscopy, Nuclear Magnetic Resonance analysis, and polyelectrolyte titration provided some initial understanding of this mechanism. This research offers valuable insights into CPAM’s interactions with metal surfaces, with important implications for environmental and industrial applications, and establishes the appropriate protocol for characterizing the intrinsic rheological properties of these materials.

The present study employed the simple co-precipitation approach followed by ultrasonication to generate a composite material consisting of magnetic Ag₃PO₄/Fe₃O₄/Chitosan(CS). The magnetic Ag₃PO₄/Fe₃O₄/CS composite was characterized using the Fourier transform infrared (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), and X-ray photoelectron spectroscopy (XPS) methods. The magnetic composite was evaluated as a photocatalyst for methylene blue (MB) degradation under visible light irradiation. The investigation also focused on optimizing the photocatalyst dose, concentration fluctuation, and stability to enhance the reaction conditions for dye degradation. The magnetic Ag₃PO₄/Fe₃O₄/CS composite exhibited robust photocatalytic activity for the degradation of MB, with a removal efficiency of 95%. Furthermore, the recyclability of the magnetic composite was evaluated for five successive cycles and the degradation efficiency was reduced to 85% only, demonstrating its robustness. The composite demonstrated exceptional recyclability and reusability while experiencing no degradation in catalytic activity. The results of this study will aid in the advancement of environmentally friendly nanotechnology by enabling the production of easily separable magnetic Ag₃PO₄/Fe₃O₄/CS composite as heterogeneous catalysts.

At the present, the spent Pleurotus substrate (SPS), which is a lignocellulosic waste from the industrial production of mushrooms, is poorly valorized and mostly landfilled. Considering the large amount of SPS that is required to produce one kilo of mushrooms and its hazard to the environment if not properly disposed of, finding means to valorize this waste is of utmost importance. This work proposes the valorization of SPS through the extraction of cellulose nanofibers (NC-SPS), by applying several bleaching and alkaline hydrolysis treatments followed by microfluidization. Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction (XRD), and thermogravimetric analysis (TGA) of NC-SPS showed that most of the lignin, hemicelluloses, and other impurities were removed after the treatments of SPS. The transmission electron microscopy analysis of NC-SPS showed the presence of nanofibers with an average width of 24.5 ± 14.9 nm, XRD indicated an increase in crystallinity from 60% for SPS to 71% for NC-SPS, while TGA showed that the onset degradation temperature increased with about 43 °C after the treatments. The new NC-SPS are similar to the nanocellulose extracted from wood and can replace it in various applications. In this work, NC-SPS were tested as modifiers for poly(lactic acid) (PLA) leading to an increase in its crystallinity, Young’s modulus (of up to 57%), and storage modulus, while preserving its thermal stability and transparency. These results showed that NC-SPS acted as good reinforcing agents for PLA, and more applications are foreseen.

In this work, new biobased polymeric materials were synthesized using interesting limonene-based multifunctional monomers as building blocks: the tetrafunctional 2,8-dihydroxy-1,9-diacrylate and 2,8-dihydroxy-1,9-dimethacrylate, and the trifunctional 2-hydroxy-1-acrylamide. These monomers were prepared by the addition reaction between the diepoxidized limonene and (meth)acrylic acid or N-hydroxyethyl acrylamide. The complete conversion of unsaturations of limonene into epoxides, as well as the formation of monomers, were confirmed by Nuclear Magnetic Resonance analysis of proton and carbon (¹H and ¹³C NMR), Fourier Transform Infrared Spectroscopy (FTIR) and Mass Spectrometry (ESI-MS). The monomeric products were polymerized via miniemulsion polymerization with different initiators and co-stabilizers, resulting in new poly(meth)acrylates and polyamide polymers, which is a hydrogel. The polymers showed a high degree of crosslinking, porosity and good thermal properties characterized by Scanning Electron Microscopy (SEM), FTIR, Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). In addition, the polymeric materials were tested to evaluate the formation of biofilm by the action of Comomanoas sp, whose results indicated that the synthesized new biobased polymers are susceptible to biodegradation.

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Poly(butylene succinate) (PBS)/poly(ethylene brassylate) (PEB) biodegradable polyester blends were prepared at different PEB contents (5 to 30 wt%) to study the influence of the addition of PEB on the rheological behavior, morphology, thermal and mechanical properties of the blends. A gradual decrease in the shear viscosities and a greater shear thinning behavior were observed with increasing PEB content due to its low molecular weight, which acted as a lubricant or plasticizer, favoring the disentanglement of PBS chains. The blends with higher PEB content (25 and 30 wt%) had higher activation energy values and were more sensitive to temperature variations. The morphology showed good dispersion of PEB in the PBS matrix. Still, increased PEB content led to larger droplets, indicating immiscibility and poor adhesion between phases. PEB influenced both nucleation density and spherulite size of PBS/PEB blends, denoted by an increasing degree of crystallinity, a shift to low crystallization temperatures, and an improvement in the decomposition temperature according to their thermal properties. Low PEB contents (5 and 10%) increased PBS toughness due to the higher crystalline fraction and smaller crystal size of these blends.

Multifunctional nanocomposite scaffolds, particularly those incorporating zeolitic imidazolate framework-8 nanoparticles (ZIF-8 NPs), are emerging as effective solutions for skin and tissue injuries due to their biocompatibility, structural stability, and antibacterial properties. Integrating ZIF-8 NPs into polymeric scaffolds has significant potential for improved tissue regeneration. This review examines recent advancements in ZIF-8 NP-integrated scaffolds, including their applications in nanofibers, hydrogels, microneedles, and 3D-printable scaffolds. It details the synthesis methods, structural characteristics, and physicochemical properties of ZIF-8 NPs, highlighting their role in enhancing wound healing. The methodological basis of ZIF-8 in wound healing applications involves its synthesis and functionalization to enhance biocompatibility, enabling the creation of drug delivery systems that release bioactive agents in a controlled manner to promote tissue regeneration and accelerate wound healing. This review highlights the biocompatibility and biosafety of ZIF-8 NPs, noting their non-toxic nature within specific concentration ranges and their multifunctional capabilities, such as antibacterial and anti-inflammatory effects that facilitate angiogenesis and infection management. The review also addresses current challenges and future perspectives in developing and clinically translating ZIF-8-based nanocomposite scaffolds as next-generation materials for improving wound healing.

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