Journal of Polymers and the Environment最新文献

This study aims to develop biobased composite films using hemicellulose (HB), methylcellulose (MC), and carboxymethyl cellulose (CMC) combined with natural additives, including high methoxy pectin (HMP), selected proteins (whey, casein, soy, and pea), and glycerol. Results showed that integrating these components significantly improved the physical qualities, peelability, foldability, and transparency, particularly in HB/CMC-based films. Mechanical properties of the films, i.e., elongation at break, tensile stress, elastic modulus, and toughness, were also enhanced by incorporating these additives. Among the combinations studied, the HB/CMC-based films with HMP, sodium caseinate (NaCas) or pea protein isolate (PPI), and glycerol (G) films exhibited the highest elongation at a break of 139%. Supplementing additives to HB, MC, or CMC-based films improved thermal stability, supported by thermogravimetry. Combining HMP/NaCas/G to HB/CMC resulted in films with the highest peak temperature (276° C). Additionally, integrating NaCas into the films also reduced oxygen and water vapor permeabilities by up to 25% and 11%, respectively, compared to their controls. Fourier Transform Infrared spectroscopy (FTIR) revealed an additive relationship between HB and MC or CMC composite films relative to their singular spectra. SEM showed a smooth compact structure, indicating a homogeneous blending amongst all components. This work demonstrated a viable solution for developing environmentally friendly bio-packaging materials based on HB extracted from corn bran, a plentiful low-value by-product of the biofuel industry’s corn kernel dry milling process combined with other agricultural-derived biomass, such as pectin, proteins, and glycerol.

Biobased adsorbents such as chitosan due to nontoxic nature, biocompatibility, and accessibility can be used to blend with other polymers to develop their physical and chemical features. This study aims to fabricate a highly efficient adsorbent through the functionalization of Chitosan- Poly(Vinylpyrrolidone) (PVP) beads with l-arginine. The prepared nano-sorbent was well characterized via various analytical methods such as FTIR, BET, EDS, XRD, FESEM, and TGA and applied in the removal of amoxicillin and Hg (II). The optimal conditions for higher performance were assessed with the optimization of different factors including pH, dosage, time, and initial concentration for both pollutants. The prepared composite has demonstrated considerable adsorption capacity toward Hg(II) and amoxicillin with the highest adsorption capacities of 313.162 mg/g and 2800 mg/g, respectively, confirming the composite’s various adsorption mechanisms. Accordingly, the composite mostly follows the pseudo-second-order kinetics and the Langmuir adsorption isotherm model. The extraordinary adsorption capacity with the accompaniment of the porous structure of the prepared composite has a promising application for high-performance wastewater treatment.

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The limitations of metallic stents have led to the development of absorbable polymer stents in cardiovascular applications. This study focuses on the synthesis of biodegradable shape memory nanocomposites made of polycaprolactone (PCL), poly(propylene carbonate) (PPC) and functionalized graphene nanoparticles (FGNp), designed for medical devices that exhibit shape memory effects at human body temperature. The nanocomposites were synthesized using a solvent casting method. To enhance the performance of graphene nanoparticles (GNPs), chemical modification with polyethylene glycol (PEG) was performed, which was confirmed by energy dispersive X-ray spectroscopy (EDX) and Raman spectroscopy. The effect of modified graphene nanoparticles on the shape memory behavior was discussed in detail and the presence of graphene showed an increase in temporary shape stabilization in the samples. In the nanocomposite with 10 wt% PCL and 0.5 phr FGNp, the shape fixation ratio (Rf) and shape recovery ratio (Rr) of about 90% were achieved with a shape memory transition temperature (Ts) close to human body temperature. This sample was successfully fabricated into a stent by a 3D bioprinter, and the fabricated stent exhibited an improved shape memory effect. Furthermore, comprehensive blood compatibility evaluations including hemolysis, cytotoxicity, and complement activation along with in vitro degradation and drug release behavior evaluations confirmed the potential of the nanocomposite PCL10/PPC90/FGNP0.5 as a promising candidate for the fabrication of biomedical stents.

The increasing use of plastic products has led to significant environmental concerns from waste accumulation and inadequate recycling, highlighting the need for sustainable solutions like biodegradable plastics. This study investigates the influence of titanium dioxide nanoparticles (TiO₂ NPs) on the structural, thermal, and mechanical properties of polylactic acid (PLA) and polyhydroxyalkanoate (PHA) polymer blends, focusing on their shape memory behavior and crystallinity. The PLA/PHA: TiO₂ nanocomposites, synthesized via solution casting, were characterized by XRD, DSC, TGA, SEM, SME, FTIR, and tensile testing. XRD analysis confirmed the incorporation of highly crystalline tetragonal TiO₂ NPs (space group I41/amd), which increased the overall crystallinity of the composites while reducing the crystallinity of the PLA/PHA blend. Thermal analysis revealed a decrease in the blend’s glass transition temperature (T_g) from 36.5 °C to lower values with TiO₂ doping, while the melting temperature (T_m) remained stable at approximately 175.3 °C. SEM micrographs demonstrated uniform nanoparticle dispersion, with surface roughness increasing at higher TiO₂ concentrations. Tensile testing showed a reduction in elasticity and a progressive increase in stiffness with increasing TiO₂ content, while UV-Vis analysis revealed a decrease in the bandgap energy to below 4 eV due to enhanced charge carrier density. This study pioneers the use of TiO₂ NPs to enhance the crystallinity, thermal stability, and shape memory properties of PLA/PHA blends, offering a promising pathway for advanced environmentally friendly material applications.

Chronic wounds significantly burden global healthcare systems, necessitating innovative solutions. Hybrid electrospun nanofibers are promising for enhancing wound healing and controlled drug delivery. This study focused on developing and characterizing hybrid nanofibrous scaffolds made from polycaprolactone (PCL), polyvinyl alcohol (PVA), and chitosan (Cs), infused with squalene (SQ) to improve healing in a rat model of full-thickness wounds. The scaffolds were created using coaxial electrospinning, with PCL as the shell and a PVA/Cs mixture as the SQ-loaded core. Characterization involved Fourier-transform infrared spectroscopy (FTIR), Scanning Electron Microscope (SEM), mechanical properties, contact angle measurements, swelling, degradation, drug release, cell attachments and cytotoxicity assays. After implantation in a rat model for 14 days, histopathological assessments evaluated inflammation, re-epithelialization, and collagen deposition. The hybrid nanofibers maintained consistent morphology with smooth surfaces and no bead formation. Diameters were 219 ± 33.4 nm for the neat scaffold and 227 ± 59.7 nm, 167.3 ± 35.9 nm, and 126.7 ± 39.75 nm for SQ2%, SQ3%, and SQ4%, respectively. SQ-loaded scaffolds exhibited reduced swelling ratio, hydrophilicity, and degradation rate, alongside improved tensile strength (194% increase in SQ4% vs. control), sustained SQ release (40% over 14 days for SQ3%), as well as considerable reducing in wound sizes (90% reduction in SQ2%). The PCL-PVA/Cs/SQ2% formulation notably reduced inflammation while promoting re-epithelialization and collagen deposition. The PCL-PVA/Cs/SQ nanofiber scaffolds demonstrated superior properties that effectively modulated inflammation and promoted wound healing. They represent a promising strategy for enhancing wound repair.

Graphical Abstract

Nano-micro scaffolds fabricated based on electrospinning and textile methods. The solution containing polycaprolactone (PCL), decellularized Wharton’s jelly matrix (DWJM) and functionalized multi-walled carbon nanotubes (MWCNTs) were electrospun on the silk fibroin treated with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide (NHS/EDC). Hybrid scaffolds (with/without MWCNTs) were compared with each other in terms of physical, chemical, mechanical, bioactivity, and biological properties. Cross-sectional view showed that the nanofibers are well seated on the NHS/EDC-treated microfibers (T-fibroin). The increase of free functional groups decreased the contact angle to 70.51°±5.22° and improved the tensile strength to 33.84 ± 3.6 MPa. The presence of NHS/EDC leads to the formation of crosslinks in the fibroin polymer network, resulting in enhanced tensile strength of T-Fibroin compared to untreated fibroin (U-Fibroin). The crosslinks within the fibroin structure and the presence of MWCNTs enhanced the crystallinity of the scaffold structure while reducing its degradation rate (1.73%). The presence of carboxyl groups in the structure of MWCNTs, DWJM and T-Fibroin improved bioactivity and enhanced the chondrocytes’ viability on the scaffold. The findings suggest using DWJM and surface chemical modification of fibroin knitted fabric is a promising approach in advancing nano-micro scaffolds. PCL-DWJM-MWCNTs/Fibroin Silk scaffold can served as a basic study for articular cartilage regeneration.

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A novel series of bio-based polyurethanes (bio-PUs) were synthesized from castor oil using hexamethylenediisocyanate (HMDI) as crosslinking agent by solvent casting method without any catalyst and further reinforced with bacterial biomass as bio-fillers. For the first time, biomasses from the biopolymer polyhydroxyalkanoate (PHA) production process, containing medium chain length biopolymer, mcl-PHA (F1) and residual bacterial biomass after the biopolymer extraction (F2), as well as bacterial biomass from the biopigment prodigiosin production process (F3) were applied as bio-fillers, resulting in PU-F1 to PU-F3 materials, respectively. The resulting functional bio-polyurethanes were characterized by various techniques including ATR-FTIR spectroscopy, SEM, X-ray diffraction, mechanical tests, transparency, water contact angle, but also cytotoxicity tests and shape memory ability were evaluated to open their applicative potential. The FTIR spectroscopy analysis confirmed the formation of polyurethane linkage. Bacterial biomass particles size and distribution reflected on the PUs properties suggesting that the type and the dispersion of the filler play an important role in the modulation of new PU materials. The water contact angle measurements revealed that PU-F1, containing mcl-PHA biopolymer exhibits higher hydrophobicity than other bio-PUs, that further reflected on better biofilm attachment in comparison to other bio-PUs. The addition of bacterial biomass containing biopigment resulted in purple dyed material of stable color over time and with the proved absence of toxicity (PU-F3). All synthesized bio-PUs appeared as non-toxic materials for human healthy fibroblast cell line MRC5. Shape memory ability was observed for the bio-PUs. The addition of variety of bacterial biomass into polyurethane matrix is a significant step towards the green conversion of resources and circular bioeconomy for plastics.

Polyethylene terephthalate (PET) is commonly used in beverage packaging and can be recycled to reduce plastic pollution, raising concerns regarding non-intentionally added substances (NIAS). Here, two organic NIAS, acetaldehyde and benzene, and metal elements have been examined in PET materials. Elemental analysis revealed that higher recycled content in PET correlated with increased contaminant levels. Moreover, elevated acetaldehyde and benzene concentrations were noticed. PET degradation, intentional addition, and unknown sources complicate the analysis of the effects of the production, recycling, and storage on the introduction, formation, or migration of NIAS in PET materials. Benzene and acetaldehyde could migrate into beverages or the environment during storage. The migration of these two volatile substances was therefore quantified. Despite their presence in all PET materials, the low concentrations of acetaldehyde and benzene detected alleviate potential health concerns. This research contributes to the understanding of how recycling and recycled content impact the presence of NIAS in PET, offering insights for optimizing recycling practices and sustaining the role of PET in environmentally responsible beverage packaging.

For the first time, this research aims to prepare a new photoluminescence and porous bio-nanocomposite of the starch nanoparticles@metal-organic framework (Manganese-Zinc) (PSt NPs@MOF(Mn-Zn)) through the composition of starch nanoparticles (St NPs), carbon dots (CDs), and MOF(Mn-Zn) in three steps. The findings of performed characterization techniques approved the success in the fabrication of the PSt NPs@MOF(Mn-Zn). In the following, the potential of PSt NPs@MOF(Mn-Zn) was evaluated as a drug carrier for co-delivery of doxorubicin (DOX) and 5-fluorouracil (5-Fu) and ((5-Fu+DOX)@PSt NPs@MOF(Mn-Zn)) was obtained. Brunauer-Emmett-Teller (BET) test showed that the surface area and total pore volume of 275.98 m² g^-1 and 0.4885 cm³ g^-1 for PSt NPs@MOF(Mn-Zn) were reduced to 3.8535 m² g^-1 and 0.0029023 cm³ g^-1 for (5-Fu+DOX)@PSt NPs@MOF(Mn-Zn) that is a good indication of the loading of studied drug molecules in the prepared system. Moreover, the higher release rate of DOX and 5-Fu at pH 5.0 than pH 7.4 is one of the main signs of the system's suitability in cancer treatment. The observation of HeLa cell viability up to 70% after treatment with PSt NPs@MOF(Mn-Zn) approved its biocompatibility and its potential for use as a drug carrier. Overall it can be concluded that the PSt NPs@MOF(Mn-Zn) has the criteria to be proposed as a new bio-nanocomposite for controlled DOX and 5-Fu delivery.

This study investigates the effectiveness of a novel metal oxide-based hydrogel nanocomposite in degrading synthetic dyes in the presence of UV light. The nanocomposite is synthesized through the insertion of metal oxide nanoparticles (NPs) into a hydrogel matrix, optimizing the material's photocatalytic properties. The successful synthesis of the hydrogel nanocomposite was verified using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). Through determination of XRD parameters, a successful synthesis of Co-CuO HNCs with an average crystallite size of 10.21 nm was confirmed. SEM images showed that after incorporating spherical-shaped Co-CuO NPs into the hydrogel matrix, the surface of the final composite became rough and fragmented with a surface area of 4.06 m²/g. Optical studies showed that the bandgap was reduced as Co-CuO NPs were incorporated into the hydrogel matrix. Photocatalytic degradation experiments were conducted using methylene blue (MB) to assess the hydrogel nanocomposite's efficiency. The results demonstrate a significant enhancement in degradation rates compared to traditional photocatalysts, due to the synergistic effects of the metal NPs and the hydrogel network. Within 120 min, the photocatalytic removal efficiency of MB reached 96% at a pH of 10 using 100 mg of the catalyst. The photocatalytic degradation process followed a pseudo first-order kinetics with a rate constant of 0.0183 min⁻¹. Moreover, scavenger studies showed that ∙OH radicals were major species responsible for the photocatalytic degradation process. The study highlighted the potential of metal-based hydrogel nanocomposites as efficient and sustainable photocatalysts for environmental remediation, offering a promising solution for the treatment of dye-contaminated wastewater. Future research will focus on optimizing the performance of the nanocomposite and exploring its practical applications in large-scale water treatment processes.