Journal of Polymer Research最新文献

Stigmasterol (Stg) is a member of the phytosterol family, which is found naturally in plants in the form of free alcohol or their sediments, especially vegetable oils, and has positive effects on health such as anti-inflammatory, anti-osteoarthritis, anti-atherogenic, antioxidant, and lowering plasma cholesterol level, and protective effects such as anti-cancer. In this study, we aimed to prepare monosize Stg-imprinted solid phase extraction polymers (Stg-Mip-MSPEs) for direct separation of Stg from soybean oil extract. The synthesized polymers were characterized by scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). Stg-Mip-MSPE has maximum Stg adsorption capacity as 73.2 mg/g while NIP-MSPE has as 8 mg/g. Selectivity studies showed that Stg-Mip-MSPEs can recognize Stg 1.45 and 2.73 times more selective than cholesterol and ergosterol molecules, respectively. The Stg rebinding capacity from soybean oil was calculated as 63.69% and also showed the selective Stg binding ability of Stg-Mip-MSPEs from real samples. The reusability studies showed that the Stg adsorption capacity of Stg-Mip-MSPEs remains 96% at the end of the tenth cycle.

Superabsorbent polymers (SAPs) with improved absorbency under mechanical load (AUL) and enhanced antimicrobial properties in hygiene applications are still challenging. In this study, chitosan was modified to prepare quaternized carboxymethyl chitosan (QCMC) to improve water solubility and antimicrobial properties and then used it as backbone to obtain a novel type of superabsorbent polymers (P(AA-AMPS/QCMC)) by introducing acrylic acid (AA) and 2-acryloylamino-2-methylpropanesulfonic acid (AMPS) monomers through grafted copolymerization. FT-IR, XRD, SEM, and TG were used to analyze and characterize the structure of samples. Different factors influencing the absorption capacity, such as neutralization degree, monomer concentration, and crosslinker content, were optimized. Conventional SAPs exhibited low AUL and slow absorption rates due to gel blockage. To overcome these limitations, surface crosslinking was applied to improve both AUL and absorption rates. The SAPs showed absorption capacities of 634 g/g in deionized water and 78.8 g/g in 0.9 wt.% NaCl solution, and reached swelling equilibrium within 30 min. With only a 3% QCMC dosage, the inhibition rates against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) were 88.9% and 87.7%, respectively. Exploratory biodegradability tests indicated that these polymers possess degradable properties. This study demonstrates the potential applications of these polymers in hygiene.

Flexible free-standing membranes (thickness ~ 60 µm) of poly (vinylidene fluoride-co-hexafluoropropylene)/polyvinyl pyrrolidone (PVDF-HFP/PVP) blends with various weight fractions of PVP were fabricated by the solution casting technique. The inclusion of PVP enhanced the semi-crystalline polymer PVDF-HFP's amorphous region, as confirmed by X-ray diffraction (XRD). Fourier transform infrared microscopy (FT-IR) investigations of the macromolecular blend membranes revealed interactions between the PVP and PVDF-HFP. The impact of adding PVP to PVDF-HFP on the miscibility of the resulting blends was examined using scanning electron microscopy (SEM). The results of thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) confirmed a complete miscibility of PVDF-HFP with PVP. Additionally, the Coats-Redfern model was used to calculate the activation energies of all samples. The uniform dispersion of PVP significantly boosted the thermal stability of the PVDF-HFP-based blend. The PVDF-HFP: PVP (75:25) blend polymer showed the minimum electrical conductivity (σ_DC) of ~ 1.23 × 10⁻¹⁴ S cm⁻¹. Adding PVP to the polymer causes additional relaxation because of the PVP/PVDF-HFP interface, which increases the blend's dielectric constant ε_r to 9.6 for the sample with 25% PVP. Dynamic mechanical analysis (DMA) showed an improvement in the storage modulus of blended polymer, with the 25% PVP sample exhibiting a storage modulus of ~ 0.23 GPa at ~ 45 °C. These advantageous improvements suggest that the PVDF-HFP/PVP blend is well-suited for insulating applications.

Metal anchoring is essential for stabilizing nanoparticles in various industrial and environmental applications. This study presents the synthesis of a novel polymer, 2-[(para-tolyl) oxy]-4,6-dichlorotriazine, functionalized with ethylenediamine, and its application in metal anchoring. The polymer’s amine-rich structure allows for effective coordination with metal ions, specifically palladium nanoparticles (Pd NPs). The synthesis process involves the substitution of cyanuric chloride followed by the formation of the polymer through a two-step reaction with ethylenediamine. Pd NPs were successfully anchored onto the polymer matrix, with the interaction between the polymer and Pd confirmed via UV–Vis spectroscopy. The particle size of the Pd-anchored polymer composite was determined by Dynamic Light Scattering (DLS), showing an average diameter of approximately 140 nm. Transmission Electron Microscopy (TEM) revealed the morphology of the nanocomposite, which consists of interconnected fibers with Pd NPs dispersed on the surface. X-ray Diffraction (XRD) confirmed the crystalline nature of the Pd nanoparticles, while Thermogravimetric Analysis (TGA) demonstrated the thermal stability of the nanocomposite. In addition to the application of polymer-metal nanocomposite in the pharmaceutical and agricultural industries, they can be used in fields such as environmental catalysis for the degradation of pollutants, as a catalyst in the synthesis of fine chemicals, and in energy-related applications such as fuel cells. The stability and catalytic efficiency of polymer-supported Pd NPs make them suitable for various industrial and environmental applications.

Durable and robust antibacterial fabrics are attracting growing attention due to increasing demands in the medical, feminine products and personal protection fields. Here, we report a simple yet effective method for embedding zinc oxide (ZnO) nanoparticles on polyester surfaces to produce an antibacterial polyester-cotton fabric with remarkable laundering and abrasion resistance. The fabric is prepared by pad-rolling, followed by hot-pressing to embed the ZnO nanoparticles onto the polyester fibers. The modified fabric achieves 100% bacterial reduction (BR) rates against both S. aureus and E. coli, exhibiting remarkable laundering durability even after 30 cycles and 600 abrasion cycles. Compared to other strategies using metal nanoparticles for antibacterial fabrics, this preparation is simple, cost-effective, low toxicity, and environmentally friendly, and effectively imparts durable antibacterial properties to fibers. This work represents a practical strategy for developing eco-friendly and cost-effective durable antibacterial textiles.

Chemically treated natural fiber-reinforced composites exhibit excellent strength, are lightweight, and have long-term durability in dry and corrosive environments. This study fabricates two types of composites, in which fibers are treated with five different chemicals such as alkaline, potassium permanganate, benzoyl peroxide, sodium chlorite, and stearic acid. The impact of various chemical treatments on the fiber surface modifies the composite's mechanical characteristics, water absorption properties, and diffusion kinetics. The properties of composites are influenced by structural elements (cellulose, hemicellulose, and lignin). To assess aging, every type of composite was soaked in a pH 8 medium for 90 days. Tensile and flexural results were validated by FEM using ABAQUS. The main objective of this study was to investigate the effective surface treatments for JUCO and banana fiber composites by various surface treatment, which could be utilized extensively in the automotive, aerospace, and marine industries to create a variety of components because of their desirable qualities, affordability, and sustainability.

Biopackaging films, such as those made from Pectin, are increasingly recognized for their sustainability in fruit preservation. This study utilizes Pectin derived from grapefruit peels to create films using evaporation casting. The research investigates factors, including Pectin concentration, sorbitol, calcium ions, and acetic acid. Film morphological and structural characterizations were performed using field emission scanning electron microscopy (FE-SEM), Energy Dispersive X-ray Fluorescence (XRF) spectroscopy, and attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR). Mechanical properties such as tensile strength (TS) and elongation at break (EAB), as well as physical properties like water vapor transmission rates (WVTR), soil biodegradation, and antibacterial capacity, were evaluated for both Pectin and Pectin/AgNPs films. The results revealed that acetic acid at a concentration of 6.67 g/L converted high methoxyl Pectin to low methoxyl Pectin, which improved gel formation. The optimal film formulation consisted of 10 g/L Pectin, 0.054 g/L calcium ions, and 5 g/L sorbitol, which enhanced film mechanical strength and soil decomposition capacity. Pectin/AgNPs films showed effective antibacterial activity against both Escherichia coli and Bacillus subtilis. Additionally, weight retention and sensory tests demonstrated that Pectin/AgNPs films successfully preserved cherry tomatoes for 10 days. Overall, Pectin and Pectin/AgNPs films show significant promise for fruit preservation, emphasizing their sustainability and effectiveness.

This research intends to explore the impact of nanographene on the dielectric, mechanical, and flame retardation behaviour of fiber composites made of snake grass fiber (SF) and Kevlar. The nanographene was evenly dispersed in the epoxy through sonication. The SF/Kevlar hybrid composites with added graphene were fabricated using compression moulding. Mechanical tests were analyzed, comprising impact, flexural, tensile, and interlaminar shear strength. The mechanical test results showed that the hybrid composites containing 3% nanographene showed an improvement of 40.66%, 46.12%, 37.33%, and 26.58%, respectively. The cracked surfaces after the tensile test were subjected to a micrographic analysis. The micrograph images revealed a strong interaction between the SF/Kevlar fiber and the epoxy, with the addition of nanographene. The dielectric test revealed that adding nanographene enhanced the dielectric loss and dielectric constant. The composite containing 5wt.% nanographene showed a 52% increase in dielectric loss compared to the reference sample. The inclusion of nanographene in SF/Kevlar hybrid epoxy composites reduces the flame propagation speed. The sample with 5 wt.% nanographene showed better performance in flammability studies. The presence of nanographene enhances the thermal resistance of the composite, delaying the ignition and reducing the overall flame spread rate.

Three epoxy binders formulated using epoxy resin ED-20 and cold-curing (Etal-23Kh), hot-curing (IMTHPA) and warm-curing (KhT-152B) agents were studied herein. Rheological, mechanical and thermomechanical behaviors of the binders were examined. All the three binders were found to exhibit a low initial viscosity of 0.5 − 1.4 Pa∙s and retain rheological properties for 3 − 5 h at 23 ⁰C (Etal-23Kh) and 40 − 60 ⁰C (IMTHPA, KhT-152B) required for composite fabrication by the wet-filament winding process. The cured binder specimens had comparable tensile strengths of 62 − 72 MPa. The glass transition temperature increased with increasing admissible temperature at which the binders underwent polymerization. For instance, the glass transition temperature was 80 − 82 ⁰C for the cold-curing binder, 111 − 113 ⁰C for the warm-curing one, and 132 − 134 ⁰C for the hot-cuing one. All the three binder formulations were employed to fabricate unidirectional basalt fiber-reinforced plastics (BFRPs). All the binders showed close elastic moduli of 40 − 43 GPa for the BFRPs. The BFRP based on the EDI binder with the IMTHPA hot-curing agent had a higher strength value of 1571 MPa and ultimate strain value of 4.16% versus 1370 MPa and 3.94% for the warm-curing binder (with KhT-152B), and 1358 MPa and 3.52% for the cold-curing binder (with Etal-23Kh). The obtained findings recommend these binders for the composite fabrication by wet-filament winding with polymerization at selective curing regimes (specific to each binder).

Polystyrene (PS) fibers were fabricated via one-step electrospinning process, using tetrahydrofuran (THF) and N, N-dimethylformamide (DMF) as mixed solvent. The properties and structure of fibers were characterized by XRD, FTIR, DSC, FESEM, BET, and tensile strength analyses. The effect of operating parameters on the fiber structure in the electrospinning process was evaluated using the Taguchi experimental design. The production of fibers with a uniform surface, dense nanopores, and bead-free morphology can be controlled by optimizing the electrospinning conditions. For this purpose, the effects of solvent composition, solution concentration, feeding rate, and applied voltage were studied. The performance of the fibers was evaluated through adsorption and selectivity tests. The adsorption capacity of the fibers was measured using three different oil sources: sunflower oil, motor oil, and crude oil. The selectivity performance of the fibers was assessed with dispersed and dissolved crude oil in water. The results revealed that the maximum oil adsorption capacities of PS fibers for sunflower oil, motor oil, and crude oil were 58.4, 68.5, and 61.1 g/g, respectively. Furthermore, the PS fibers demonstrated excellent oil–water selectivity in the treatment of oily water. Moreover, polyaniline (PANI) was incorporated as a conductive polymer to enhance the properties of electrospun fibers. The conductive fibers exhibited improved microstructural properties and performance compared to PS fibers. The motor oil adsorption capacity increased to 71.5 g/g with the conductive PS/PANI fibers. The results of this study demonstrate that the conductive and hydrophobic PS/PANI fibers, as selective adsorbents, possess a high capacity for the adsorption of various oils.