Journal of Polymers and the Environment最新文献

A series of interpenetrating polymer networks (IPNs) were prepared in the film form using 2-hydroxypropyl methacrylate (HPMA) polyethylene glycol methacrylate (PEG-MA) and hydroxypropyl-chitosan (HPCH) for controlled release of 5-fluorouracil (5-FU). The prepared IPNs formulations have been characterized using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), swelling, and contact angle studies. In addition, the platelet adhesion, red blood cell hemolysis, and permeability to 5-FU were also studied with prepared IPNs films. The prepared p(HPMA-co-PEG–MA/HPCH)-1-6 IPNs films were loaded with different amounts of 5-FU and the drug release was studied in a continuous release system. The drug 5-FU has four amine and oxygen groups, and these functional groups interact via hydrogen bonding interaction with PEG-MA and HPCH units of the IPNs, thus, the drug was slowly released. The amount of 5-FU release from the p(HPMA-co-PEG–MA/HPCH) networks increased when the ratio of HPMA decreased or HPCH increased. The antitumor activity of 5-FU released from the prepared IPNs and remaining biological activity was measured using a human hepatocellular carcinoma cell line (SNU398). In vitro studies showed that the tested IPNs formulations were effective for the growth of the SNU398 human hepatocellular carcinoma cells. These experimental results showed that the prepared IPN films exhibited suitable physio-chemical, biocompatibility, and desired drug release profiles, thus, they could be used in various biomedical applications such as wound dressing for skin treatment.

Bone tissue engineering has emerged as an innovative approach for repairing and regenerating bone defects. This study focuses on the development of new scaffolds with key attributes, including biocompatibility, bioactivity, biodegradability, cost effectiveness, and safety. In this investigation, we designed and synthesized a novel nanofibrous scaffold using the electrospinning method, incorporating zein/58S bioactive glass. The manufactured scaffolds underwent comprehensive characterization for morphology, sustainability, and chemical structure. Moreover, to demonstrate their efficacy in bone healing, we quantified essential factors such as biodegradation rate, contact angle, mechanical strength, bioactivity, cytotoxicity, and cell adherence. Following that, the osteogenesis effect of scaffolds was evaluated in vitro as well as in vivo through implanting them in the calvarium of the rats. Specifically, we conducted detailed investigations using alizarin red staining, real-time PCR, and histopathology, along with immunohistochemistry assessments. Based on our results, the fiber diameters were about 160.2 ± 7 nm, 163.5 ± 38.3 nm, and 164 ± 39.3 nm, respectively for zein, 2%BG, and 4%BG mats. Incorporation of 58 S increased contact angle from 96.03 ± 0.7° to 51.7 ± 2.02°, and consequently improved cell adhesion. The degradation rate of all scaffolds was about 20%, and chemical analysis (FTIR) confirmed the presence of 58 S in zein nanoscale mats. Tensile analysis presented that applying bioactive glass rescued Young’s modulus from 0.34 ± 0.07 to 0.08 ± 0.009 MPa. Meanwhile, other results revealed that 4%BG scaffolds exhibit desirable properties, being porous, safe, bioactive, and osteogenic. These findings robustly affirm the competence and potential of the manufactured nanofibrous scaffold containing 4%BG for applications in bone tissue engineering.

Graphical Abstract

The schematic diagram illustrating different stages of the study, including; zein/BG scaffold synthesis, characterizations and osteogenesis evaluation in vitro and in vivo

Polyurethane, a hydrophobic polymer with limited water solubility, is widely employed in applications including foam insulation, adhesives, coatings, and both flexible and rigid plastics. Waterborne polyurethane (WBPU) has emerged as a focal point due to its water-dispersible nature Its beneficial qualities, such as low emissions of volatile organic compounds (VOCs), simplicity of use, and environmental friendliness, are the reason for its appeal. WBPU is recognized for being non-toxic, non-flammable, and low VOC properties so it can help prevent the pollution of air water rather than increase. Moreover, it exhibits remarkable adhesion properties to a wide range of surfaces, such as glass and polymeric fibres. These exceptional qualities of WBPU have piqued the interest of researchers worldwide. This review focuses on the fundamental principles of WBPU chemistry and explores its physical attributes. It proceeds to provide an extensive examination of various studies, shedding light on the reaction procedures and mechanisms involved. Additionally, the article delves into the modifications introduced in the production process, the selection of source materials, and associated limitations.

The presence of Persistent Organic Pollutants (POP) in consumer products such as electrical and electronic equipment represents a major obstacle for the recycling of the materials they contain at their end-of-life. Current technologies applied to recover plastics from waste electric and electronic equipment (WEEE) struggle to meet the requirements from recyclers regarding restrictions on some of these POPs, mainly brominated flame retardant (BFR) content. In this study, laser-induced breakdown spectroscopy (LIBS) technique combined with partial least squares regression (PLSR) was investigated for the real-time classification of WEEE plastics based on their total bromine (Br) content, in order to foster their reintroduction into the market as secondary raw materials. With this aim, a classification method was trained and tested in a sorting prototype using mixed plastic samples from TV set and computer monitor housings containing an average of 1.34% of Br. Regardless of polymer colour and type, up to 56% of the tested material could be segregated into a single fraction with a final Br concentration of 1,280 mg/kg. The achieved values met the requirements established in the CENELEC EN 50625 series of standards for the depollution of BFRs (< 2,000 mg/kg of Br) and the concentration of polybrominated diphenyl ethers (PBDEs) was estimated to be 213 mg/kg. These findings demonstrate the potential of the LIBS technique together with multivariate data analysis to ensure WEEE plastic sorting and depollution compliance with current regulations, reducing disposal rates and ultimately contributing to its circularity.

The development of sustainable polyurethane (PU) materials is crucial for minimizing the environmental impact of conventional solvent-based PUs. This study presents a novel approach to synthesizing and characterizing an imine-containing self-healing waterborne polyurethane (WPU) coating derived from bio-based polyester polyol. The process involves the synthesis of an imine-containing diol (IM-diol) from terephthalaldehyde and ethanolamine, followed by the creation of a series of bio-based dynamic bond-containing WPU using bio-based polyester polyol, IM-diol, isophorone diisocyanate (IPDI), and other additives. The imine dynamic bonds within the WPU exhibit excellent self-healing, reprocessability, and degradability. The mechanical and thermal properties of the synthesized bio-based WPU materials were characterized. Dynamic light scattering (DLS) results showed excellent stability in the prepared imine-containing WPU particles. Scratched WPUs exhibited practical self-healing ability at 80 °C after 30 min. The reprocessed imine-containing WPU grains fully recovered their mechanical properties (healing efficiency of 95%) for the first time. Thermogravimetric analysis (TGA) revealed that the thermal decomposition temperature of the synthesized imine-containing WPU exceeds 230 °C, indicating high thermal stability and potential for high-temperature applications. This study provides a promising method to produce a bio-based WPU elastomer with robust self-healing subjected to a dynamic exchange reaction under mild conditions. The findings suggest promising applications for bio-based WPUs in various fields, including coatings and adhesives, highlighting their potential for sustainable solutions in industries that require robust performance. The outstanding properties of the synthesized materials inspire confidence in their potential for various applications and the exploration of new uses that meet both performance and sustainability criteria.

Graphical Abstract

Polyurethanes (PUs) are widely utilized in various industries due to their versatile properties. Traditionally, these polymers are synthesized using petrochemical-based polyols, which pose environmental concerns. To address this issue, there is a growing trend towards the use of bioresources in polymer manufacturing. This study explores the synthesis of a Schiff base diol derived from ethylene diamine (EDA) and vanillin, which can be obtained by depolymerization of lignin. Additionally, a soybean oil-based polyol (SOP) was employed as a sustainable alternative to traditional petroleum-based polyols. The synthesized Schiff base diol and SOP were used to prepare PU films, incorporating both aromatic and aliphatic diisocyanates which are methylene diphenyl diisocyanate (MDI) and hexamethylene diisocyanate (HDI), respectively. The primary objective was to investigate the impact of the aromatic and aliphatic nature of the isocyanates on the properties of the resultant PU films. The thermal stability and mechanical properties of the PU films were evaluated and compared. The results demonstrate that the bio-based PU films exhibit good thermal stability. However, contrary to expectations, the mechanical strength decreased with an increasing amount of Schiff base diol, while the elongation percentage increased. A flammability test was also performed to assess flame retardancy, and an unexpected trend was observed in HDI-containing PU films, which is discussed in detail in the manuscript. The study highlights the potential of using bioresources, such as vanillin and soybean oil, to produce sustainable and thermally stable PUs, paving the way for more environmentally friendly applications in the polymeric industry and beyond.

This study investigates the feasibility of recycling waste banknotes into cellulose acetate (CA), aiming to provide a sustainable solution for managing this challenging waste stream. The research goals were to successfully convert banknote cellulose into CA and compare its properties with commercial cellulose acetate (CCA). Methodologies employed include acetylation of waste banknote cellulose, followed by comprehensive characterization using Fourier-transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and rheological measurements. Additionally, the study assessed the degree of substitution, polymerization, heavy metal content, tensile strength, moisture absorption, and thermal stability of the produced CA. Key findings demonstrate successful acetylation of banknote cellulose, confirmed by FTIR analysis. The laboratory-produced cellulose acetate (LCA) exhibited comparable tensile strength (2.02 MPa) and porosity (10.3%) to CCA. Notably, LCA showed significantly lower elongation (32% vs. 37% for CCA) and reduced moisture absorption, indicating superior ductility and dimensional stability. Thermal analysis revealed typical CA decomposition behavior, with onset around 300 °C. Rheological studies showed favorable non-Newtonian, shear-thinning behavior, suggesting good processability. These results demonstrate that waste banknotes can be effectively converted into CA with properties comparable or superior to commercial products, offering a promising avenue for value-added recycling of this waste stream and contributing to circular economy principles.

This study aims to modify bacterial cellulose (BC) produced by Komagataeibacter nataicola TISTR 975 with collagen hydrolysate (CH) and Quercus infectoria gall (QI) via an ex-situ method to develop a bioactive wound dressing. Initially, QI gall was extracted in ethanol, and the crude extract showed a high total phenolic content (TPC) of 778.7 ± 76.2 mg GAE/g. After loading CH and QI onto the BC film, the morphology, FTIR spectra, mechanical properties, antibacterial properties, and biocompatibility of the prepared films were systematically evaluated. SEM images revealed that all prepared films were porous with multiple layers, and FTIR results confirmed the successful incorporation of CH and QI into the BC film. The TPC on the films ranged from 149.7 to 563.1 mg GAE/g, depending on the QI loading concentration. The tensile strength of the BC/CH/QI films was higher, while Young’s modulus and % elongation at break were comparable to the BC. The swelling ratio of the composite films was increased to nearly doubled, which can be attributed to the high-water absorption capacity of CH. Moreover, disk agar tests revealed that adding QI in the BC film significantly inhibited the growth of Escherichia coli and Staphylococcus aureus. Hemolysis assay results supported that the BC/CH/QI films were biocompatible. Overall, the results of this study demonstrate that the BC/CH/QI films are considered as a bioactive material and has the great potential for biomedical applications.

In the present study, a novel pH-sensitive nanocarrier was prepared by grafting chitosan/polyvinylpyrrolidone (CS/PVP) on the surface of single-walled carbon nanotubes (SWCNTs). Levofloxacin (LVX), an anti-bacterial model drug, was loaded onto the resulting nanocomposite. The as-prepared nanocomposite was characterized using field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD) techniques. The adsorption procedure was investigated under different sorption conditions, such as solution pH, adsorbent dosage, initial drug concentration, contact time, and temperature. The experimental data were analyzed using both non-linear and linear forms of kinetic and isotherm models. Based on the sum of squares errors and coefficient of determination values, the non-linear forms of the pseudo-2nd-order kinetic model and Langmuir isotherm model provided the best fit to the experimental data. Adsorption thermodynamic showed an exothermic and spontaneous nature of the drug sorption on the surface of the nanoadsorbent. In-vitro drug release tests were studied in simulated gastric fluid (SGF; pH = 1.2) and intestinal fluid (SIF; pH = 7.4) at 37 °C. The pH-sensitive nanocarrier indicated sustained drug release over 36 h. Nearly 99.76% of the drug was released in simulated intestinal fluid at pH = 7.4 in 36 h and 22.72% was released in simulated gastric fluid at pH = 1.2 in 30 min. The drug release profiles were well-fitted by the Korsmeyer-Peppas kinetic model, and the release mechanism of the nanocarrier was related to non-Fickian transport. Furthermore, the antimicrobial efficacy of the fabricated nanomaterials was evaluated against Staphylococcus aureus (Gram-positive). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the nanoparticles were subsequently quantified.

There is a significant demand in the biomedical field for shape memory polymers (SMPs) with adjustable biodegradation rates, desirable transition temperatures, and viscoelastic characteristics, as they are essential for implantable medical devices and tissue engineering applications. This research presents the successful development of antibacterial bioscaffolds using a copolymer of acrylated epoxidized soybean oil and hydroxyethyl methacrylate (AESO-co-HEMA) for biomedical applications through digital light processing (DLP) 3D printing. The 3D-printed samples were characterized in terms of mechanical properties, thermal behavior, shape memory effects, biocompatibility, and antibacterial activity. Rheological analysis indicated that the viscosity of the AESO-HEMA inks ranged from 0.23 to 0.41 Pa·s, suitable for DLP 3D printing. Characterization analysis confirmed successful copolymerization, with high gel content (87.4-92.5%) and glass transition temperatures (T_g) between 33.2 °C and 51.3 °C, suitable for biological environments. Mechanical testing indicated that the tensile strength of the scaffolds ranged between 16.3 and 21.1 MPa, with elongation at break between 12.2% and 18.8%. The shape memory behavior was excellent, with a recovery ratio (R_r) exceeding 98%. Antibacterial tests demonstrated significant activity for the curcumin-loaded sample against Staphylococcus aureus and Escherichia coli. Moreover, drug release studies showed a sustained release of curcumin over 10 days. In-vitro biodegradation studies revealed a mass loss of approximately 8.5% over 8 weeks. Furthermore, cell viability assays confirmed high biocompatibility, with L929 fibroblast cells showing significant proliferation and viability on the scaffolds. These findings suggest that AESO-co-HEMA bioscaffolds are promising for various biomedical applications, including tissue engineering and implantable devices, due to their mechanical robustness, biocompatibility, antibacterial properties, and shape memory effects.