Journal of Polymers and the Environment最新文献

The need for the production of synthetic polymers from renewable and sustainable resources also affects the area of emulsion polymerization. The bio-based monomer (BBM) was synthesized from camelina oil (CO) and itaconic acid through transesterification and epoxidation of CO, followed by itaconation, resulting in a blend of methyl esters of CO-originated fatty acids functionalized with reactive methyl itaconate groups. Various amounts of BBM (0−30 wt% of BBM in the total monomer mixture) were copolymerized with standard petroleum-based acrylic monomers (specifically methyl methacrylate, butyl acrylate, and methacrylic acid) using the emulsion polymerization technique to obtain film-forming latexes. Infrared and Raman spectroscopies evidenced the successful incorporation of BBM into the structure of latex polymers. The ultra-high molar mass nanogel fraction was detected by asymmetric flow-field flow fractionation coupled with a multiangle light scattering (AF4-MALS) for the BBM comprising copolymers; the higher the BBM content, the more extensive the nanogel fraction. Cross-linking of latex polymers induced by BBM testified to the reactivity of itaconated functions in emulsion polymerization and provided additional evidence of the copolymerization ability of BBM. The incorporation of BBM also resulted in pendulum hardness and glass transition temperature enhancement (about 11% and 9 °C, respectively, in the case of 30 wt% of BBM content in contrast to 0 wt% of BBM content in the copolymer). Coatings with excellent transparency and gloss were obtained from all latexes regardless of the BBM content used. Slightly increased water repellency (about 7 ° increased water contact angle value) and significantly improved water whitening resistance of the coatings (about 80% decreased water whitening after 1-day long water exposure) were found for coatings comprising 30 wt% of BBM in the copolymer, where the water whitening phenomenon was highly dependent on the BBM content.

This study examined the effects of adding Polyethylene-octene elastomer modified with maleic anhydride (POE-g-MA) as a compatibilizing agent, along with bioactive glass particles (BG), to a blend of polyamide 6 (PA6) and poly (lactic acid) (PLA). The research focused on analyzing the morphology, rheological behavior, thermomechanical characteristics and shape memory capabilities of the resulting composite materials. Utilizing Field Emission Scanning Electron Microscopy (FE-SEM) and Transmission Electron Microscopy (TEM), it was found that the inclusion of the compatibilizer and BG significantly improved dispersion and phase interactions within the matrix, which was linked to enhanced interfacial adhesion. The addition of BG also contributed to greater thermal stability, as indicated by a rise in the activation energy (Ea) required for thermal degradation of the samples. Contact angle and degradation analysis indicate good biocompatibility and biostability of composites. Mechanical tests demonstrated notable improvements in Charpy impact strength and tensile strength for the “P80/L20/C5/BG10” sample, showing increases of over 120% and 56%, respectively, compared to the PA6/PLA blend without additives. Rheological studies revealed that the inclusion of both the compatibilizer and BG modified the viscoelastic characteristics of the samples, with zero shear rate viscosity and relaxation time increasing as BG content rose, in line with the Carreau-Yasuda model. Additionally, the combined effects of the compatibilizer and BG significantly enhanced the polymer’s ability to retain its shape, resulting in enhanced recovery factor (Rf) and recovery rate (Rr). This research highlights the potential of using POE-g-MA and BG to improve the performance attributes of PA6/PLA composites for advanced applications, demonstrating significant improvements in morphology, thermal stability, mechanical strength, rheological behavior, shape memory capabilities, and biomedical uses.

The control of the surface topography of biomaterials is a key factor for the management of post-implantation recovery processes. The study of the influence of the nanorelief of polyhydroxyalkanoate (PHA) films on the functional state of cells involved in tissue healing process is important for the development of biocompatible materials for tissue engineering. In this work, polymer films based on polyhydroxyalkanoates of various compositions with different surface relief were analyzed. The effect of the nanorelief of PHA films on the morphology, adhesion and proliferation of cells involved in regenerative processes in tissue damage (erythrocytes, macrophages, fibroblasts) was evaluated. According to the obtained results, it was found that all films samples based on polyhydroxyalkanoates of various compositions have high biocompatibility and do not cause any pronounced negative cellular reactions. However, differences in cell morphology, adhesion, and proliferation were noted between film samples. In the case of P3HB films, a slight activation of local inflammatory reactions was noted. Thus, P3HB matrix is less preferable for use in restoration of soft tissues. On the other hand, films based on P3HB3HV demonstrated high biocompatibility, which allows to conclude that this copolymer matrix is promising for use in tissue engineering.

Carrageenan, a natural polysaccharide derived from red algae, has garnered significant attention for its versatile applications in biomedical, pharmaceutical, and material sciences because of its inherent biological and gelling nature. Moreover, its intrinsic properties, including gel-forming ability, biocompatibility, and tunable viscosity, make it a valuable material for drug delivery, tissue engineering, and food technology. However, these properties can be further enhanced or tailored through chemical and structural modifications per the requirements of biomedicine. This review explores various modifications of carrageenan, such as functional and ionic modifications, that alter its physiological and biomedical properties. Common changes in hydrophobicity were found through the addition of extra carbon chains and functional groups; moreover, ionic changes also affected hydrophobicity and cancer cell selectivity in the case of barium ions, which were analysed through the encapsulation of a water-insoluble drug. The conductivity was also enhanced by ionic changes as well as the addition of aromatic groups to carrageenan, which could be utilized for ionic moments in tissue engineering and ion-linked targeted drug delivery. Overall, all of these modifications were crucial for resolving the limitations of the parent polymer (toxicity, conductivity and excessive hydrophilicity), expanding its range of possible uses and expanding its use in targeted drug delivery, cancer therapy, wound healing, and smart material development. This review delves into the underlying mechanisms of these modifications and highlights their impact on the biomedical and material science applications of carrageenan, providing a pathway for future innovations in this field.

Nowadays, most of the chemical recycling approaches for plastic waste aim primarily for the depolymerization of single polymer plastics or the multiple steps depolymerization of a plastic mixture which in both cases is considered time, cost and energy consuming. Herein, we present an optimized, single step approach for non-catalyzed hydrolysis of multiple polyesters in Poly(lactic acid) (PLA) mixed plastics under mild conventional heating. The proposed depolymerization process simultaneously breaks down plastic polyesters (mainly PLA and polyethylene terephthalate (PET)) into their value-added monomers; lactic acid in the form of Ca lactate and terephthalic acid (TPA) which are further separated and purified in a reduced number of steps. Box-Behnken Design was employed to maximize the conversion of plastics and the yields of the produced monomers through optimization of the depolymerization and monomer extraction conditions, all while adhering to the green chemistry principles. Within 30 min, and at 85 ⁰C temperature, the proposed hydrolysis technique facilitated 83–100% conversion of various PLA products (PLA Polymaker fibers (containing PLA, PET and other additives), PLA pellets and postconsumer PLA cups) into 763.8-929.6 mg/g_plastic Ca lactate and 51.5 mg/g_plastic TPA if PET was present. The proposed non-catalyzed process followed first order reaction kinetics with a small activation energy of 78.92 kJ/mol, resulting in an acceptable total energy consumption of 176.0 kJ/g_plastic. The obtained monomers’ identity and purity were confirmed by FTIR analysis. Additionally, the waste reagents produced during the depolymerization and monomer extraction processes were regenerated for reuse in another cycle of depolymerization while maintaining good performance. The developed approach offers an economically attractive and ecologically sustainable solution for energy and cost-efficient recycling and upcycling of post-consumer plastic waste containing PLA combined with other polyesters.

Poly(hydroxybutyrate) (PHB) is a biodegradable and biocompatible polyesters synthesized by bacteria for carbon and energy storage. Given its mechanical properties comparable to those of polypropylene, PHB represents a viable alternative for reducing conventional plastic pollution. However, the high production costs associated with traditional carbon sources, such as glucose, remain a significant barrier to large-scale PHB. In this study, an alternative carbon source derived from the interaction between whey and demerara sugar was evaluated for the optimization of PHB production by mangrove- isolated bacteria. The Central Composite Design data indicated that whey concentration at its upper axial point (39.99 mL∙L⁻¹), and demerara sugar at its central point (20 g∙L⁻¹) as the most favorable conditions for PHB production. Fermentation experiments utilizing this combination for 48 h with an isolate identified as Bacillus cereus, resulted in the highest cell biomass production of 2.9 g∙L⁻¹, and a polymer recovery rate of 67.39%, corresponding to 2 g∙L⁻¹. The characterization of purified polymer using FTIR, DSC, TGA/DTG, SEM and GC-MS confirmed the biopolymer as poly(hydroxybutyrate) (PHB). These findings provide information on efficient fermentation parameters using whey as strategies of conversion into bioplastics and highlight the potential of B. cereus isolated from mangroves for future industrial-scale production.

Due to the increasing adverse environmental effects of synthetic polymers, the need for environmentally friendly alternative biomaterials is increasing daily. In this context, the synthesis of novel Poly(vinyl alcohol) (PVA) -based composite materials was aimed. In this study, methacrylate-based poly(2-oxo-2-[4-(trifluoromethyl)anilino]ethyl-2-methylprop-2-enoate) (PTFMAM) polymer synthesized for the first time was blended with PVA by hydrothermal method. Biosynthesized silver nanoparticles (Ag NPs) were added to the PTFMAM-PVA blend using the hydrothermal method. Nanocomposites were characterized by XRD, SEM, TEM, and FTIR. The thermal stability of nanocomposites was determined by thermogravimetric analysis (TGA), and glass transition temperatures (Tg) were determined by differential scanning calorimetry (DSC) techniques. According to TGA data, the thermal stability of PVA was improved by blending with PTFMAM and loading with Ag NPs. While the Tg of PVA and PTFMAM-PVA were 78 °C and 103 °C, this value increased to 116 °C with 7% Ag NP loading. The dielectric properties of the nanocomposites also increased with the loading of Ag NPs. Ag NPs loading also decreased the solubility of PVA in water. Combining PVA with PTFMAM and Ag NP increased the oxidant/antioxidant activity. At the same time, increases in the antimicrobial activities of the nanocomposites were observed. The inhibition zones of the nanocomposites against E. coli, S. aureus, and C. albicans strains were between 8.56 and 15.08 mm. The results showed that PVA equipped with synthetic PTFMAM and biosynthesized Ag NPs caused improvements in thermal, dielectric, and biological properties. The produced PTFMAM-PVA/Ag nanocomposites showed that they could be alternative materials in areas where PVA is frequently used with their improved properties.

Poly(glycolic acid) (PGA) possesses widespread interest due to its outstanding degradability as well as mechanical performance, however, its poor toughness restricts their application. In this work, we synthesized biobased poly(butylene 2,5-furanoate) (PBF), then added a small amount by melt extrusion into PGA to achieve a balance between toughness and mechanical properties of PGA. The incorporation of PBF significantly enhanced the tensile toughness and impact toughness of PGA. Specifically, when the PBF content reached 50 wt.%, the blend exhibited a maximum elongation at break (121.2%), which was 18.9 times higher than that of pure PGA. However, owing to no changes observed in terms of chemical structure, crystal structure, and compatibility before and after blending, it can be concluded that the improvement in material toughness is not attributed to any chemical reactions or compatibility alterations between PBF and PGA. Based on the rheological characterization and morphological analysis of SEM, it has been demonstrated that the shape alteration of PBF serves as the primary mechanism for toughening PGA. Due to the excellent barrier properties of PBF, the addition of PBF makes the barrier properties of the blend better maintained. Thus, this work prepares a sustainable PGA/PBF blend with excellent strength and barrier properties via melt-blending method, which show great potentials in high-barrier application scenarios such as food packaging.

The current study brings in the nano-architectonics and chemical production of Au NP doped polydopamine (PDA)-modified Zn–Al-LDH or layered double hydroxide (Zn-Al LDH@PDA). The green synthesized Au adornednano-substance has been so novel where the support Zn-Al LDH@PDA provides the necessary protection ofAu NPs by encapsulation. The polyamino atmosphere in the surface of the PDA facilitates the strong binding or coordination of incoming Au ions.In order to ascertain the physicochemical properties of the material, we utilized an extensive array of advanced techniques in this process, such as elemental mapping, FT-IR, FE-SEM, EDX, TEM, HR-TEM, FFT, ICP-OES, N₂ surface adsorption-desorption, and XRD. Subsequently we evaluated catalytic exploration of the Zn-Al LDH@PDA/Au nanocomposite to reduce the harmful dyes of water like Methyl Orange, Methylene Blue and 4-nitrophenol using NaBH₄ as the hydride donor. The outstanding potential of the catalyst was then confirmed by using a time-dependent UV-Vis spectroscopy approach to monitor the chemical reaction and see how the absorptions decreased with time. It was also clear the reaction rate is proportional to catalyst load and kinetic study assured the reaction to be of pseudo-first order. In the end, we managed to isolate the nanocatalyst through centrifuger and found it sufficiently robust so that it could be recycled in an 8successive period with no significant decline in reactions.

Using CO₂ as a building block to produce monomers through carbonation (cycloaddition reaction) provides an attractive approach to carbon dioxide valorization. The design of an efficient, cheap, and reusable catalyst for epoxide carbonation remains a challenge. In this paper, a new quaternized chitosan catalyst, useful for the cycloaddition of CO₂ to epoxides, was developed. The new catalyst was obtained using a short and straightforward route, including the use of non-depolymerized chitosan and benign reactants such as succinic anhydride (a food additive), at room temperature. The catalyst allowed the carbonation of glycidyl methacrylate at 100 °C, 2 MPa, and 6 h reaction without any solvent required, with 98% epoxide conversion and 87% selectivity to the carbonated product. The catalyst was reused during 3 cycles showing stable values of conversion and selectivity to the carbonated GMA. The selectivity to the carbonated GMA remained stable at 87% during seven recycles. The use of non-depolymerized chitosan as a precursor is a key point that brought durability to the catalyst in comparison to depolymerized chitosan. The catalyst was also used in the carbonation of two di-epoxides (1,4-butanediol diglycidyl ether and bisphenol A diglycidyl ether) at 100 °C and 2 MPa affording high yields to the carbonated products.