Journal of Applied Polymer Science最新文献

Development of a cost-effective and environmentally friendly method to treat dye wastewater is of utmost importance. In this experimental study, wastepaper was used as the raw material for the extraction of cellulose nanocrystals to fabricate a nanocomposite membrane with chitosan. During the extraction process, acid hydrolysis (Sulfuric acid) followed by bleaching (hydrogen peroxide) was adopted. To confirm the nano-range, particle size analysis, and FESEM were performed, which confirmed the presence of particles in the nano-range ranging from 313.8 to 122.1 nm and FESEM observed results showed transformation of fibrous to rod shaped nanocrystals after acid hydrolysis. After successful nanocomposite fabrication a porous sieved network of membrane was observed and after adsorption successful adhesion of dye molecules over the membrane matrix was also confirmed. FTIR data showed that during adsorption mechanism some of the prominent peaks gets disappeared suggest interaction of dye molecules onto the nanocomposite. The contact angle of 21.0° was observed for the ChNC₃ nanocomposite showed super hydrophilic behavior. Tensile strength was also observed in terms of young's modulus, ultimate strength, and elongation at break. The elasticity and stiffness of a material are usually indicated by its young modulus. In AH CNCs and ChNC3, the young modulus was seen to be increasing from 195< 693, respectively. On the other hand, the ultimate strength indicates AH CNCs and ChNC3 and shows a downward trend of 1.56> 0.316, respectively. Furthermore, the potentiality of the nanocomposite membrane was analyzed for Congo red dye in synthetic wastewater prepared in the laboratory. During the batch study, various working parameters were taken such as initial dye solution (20–100 ppm), pH (1–7), contact time (10–60 min), and dosage (0.1–0.5 mg/L). To know about adsorption, Langmuir and Freundlich isotherm were analyzed it was observed that Freundlich isotherm show best fitted modeling with R² = 0.99, and n = 1.6 showing favorability of the heterogeneous adsorption. To determine the interaction between the adsorbate and adsorbent, pseudo first order and pseudo second order kinetics models were analyzed, and it was observed that chemisorption interaction followed between the adsorbate and adsorbent. Thermodynamic parameters were analyzed, which confirmed the spontaneous and favorable adsorption mechanism. To avoid fouling problems and maintain cost effectiveness, the resulting, nanocomposite membrane was desorbed using an appropriate solvent. After 5 cycles, the desorption rate decreased from 54% to 38%. This developed nanocomposite membrane appears to be effective in effluent waste treatment because of its simple formulation approach.

Metal–organic frameworks (MOFs) have garnered significant attention in recent years due to their potential application in flame-retardant polymeric materials. In this work, Fe₂O₃/ZnFe₂O₄/g-C₃N₄@ZIF-8 flame retardants were synthesized via solvothermal and calcination techniques, and their elemental composition and morphologies were thoroughly characterized. The flame retardancy of polyurea (PUA) composites incorporating varying dosages of these flame retardants was evaluated using cone calorimetry tests (CCT). The findings demonstrate that the incorporation of Fe₂O₃/ZnFe₂O₄/g-C₃N₄@ZIF-8 significantly enhanced the flame retardant properties of PUA composites. With the addition of 3 wt% of the flame retardant, the peak heat release rate (PHRR), total heat release (THR), total smoke production (TSP), and total CO yield (TCO) of the PUA composites decreased to 890.82 kW/m², 131.34 MJ/m², 12.30 m², and 2.39 g, respectively, reflecting reductions of 33.59%, 18.59%, 29.40%, and 47.93% compared with pure PUA. The flame-retardant mechanism was systematically analyzed in both the condensed and gas phases. This study provides a robust experimental foundation and novel insights that contribute to the development of advanced flame-retardant coating materials.

Polymer dielectrics with excellent energy storage properties are crucial for high-power density electronic equipment in environments such as high temperatures and strong electric fields. They play a critical role in applications including hybrid electric vehicles, electromagnetic launch devices, and photovoltaic power generation. In this paper, the small molecule compound lithium acetate (LiAc), which is low cost and exhibits good thermal stability in high-temperature environments, was selected and blended with a polyetherimide (PEI) polymer matrix at an ultra-low loading (≤0.3 vol%). LiAc has a higher electron affinity compared to PEI, which will result in a large trap energy level (Φ_e). The injected and excited electrons are trapped by strong electrostatic attraction, which suppresses carrier transport, reduces conduction losses, and improves breakdown strength in high-temperature environments. This composite dielectric exhibits better energy storage properties in high-temperature environments. The energy density of the 0.2% by volume LiAc/PEI composite dielectric reaches 3.04 J cm⁻³ at 150°C, maintaining an energy storage efficiency of approximately 90%. The research presented in this paper offers a novel approach to achieving excellent energy storage properties in polymer-based composite dielectrics operating in high-temperature environments.

The study of sorption and diffusion characteristics of glassy polymers based on polyamide-imides was carried out using the methods of static sorption, dilatometry, electron microscopy. Water sorption isotherms of polyamide-imides based on trimellitimido-N-acetic acid (PAI-A) and trimellitimido-N-p-benzoic acid (PAI-B) with different intramolecular ‘hinges’ in the diamine fragment were obtained. The isotherms are S-shaped and occupy an intermediate position between polyheteroarylenes and aliphatic polyamides. The dual sorption model was used to interpret the results. It is shown that the Langmuir component of the isotherms is determined by the thermal prehistory of glassy polymers, while the sorption component associated with water dissolution according to Flory-Huggins is determined by the chemical nature of the functional groups included in the monomeric unit. The diffusion coefficients of water and the temperature and concentration dependences of the diffusion coefficients of sorbed water molecules were determined.

This study aimed to explore the influence of film thickness on the piezoelectric efficiency of polyvinylidene fluoride/graphitic carbon nitrate nanosheet (GCN) composite films, taking into account the effect of GCN alignment. Our findings demonstrated that the piezoelectric performance of these films was markedly dependent on their thickness. We have observed a direct relationship between film thickness and piezoelectric efficiency, with thicker films showing a greater capability to convert mechanical pressure into electric energy. This increased efficiency is attributed to the enhanced ability to thicker films to distribute stress uniformly across the material, which is crucial for optimizing the piezoelectric effect. Our results advance the understanding of how variation in film thickness impact mechanical properties such as stiffness and flexibility, which subsequently affect the piezoelectric response. Through predictive modeling, we analyzed the mechanical dynamics of film displacement under an electrical potential and clarified how different thickness influenced the mechanical properties and piezoelectric output. This detailed analysis deepens the fundamental understanding of material design for optimal piezoelectric performance and underscores the critical role of film thickness in engineering application.

Membrane-based CO₂ separation is a promising technology compared to traditional processes, presenting advantages such as superior energy efficiency and reduced operational costs. This study investigates the enhancement of CO₂/N₂ separation performance by incorporating ionic liquid [hmim][Tf₂N] into polysulfone membranes. The membranes were produced with 5, 10, and 20 wt% IL, and their permeability was measured at 25°C under pressures of 1 and 4 bar. Stability tests were also conducted. At 1 bar, the membrane with 20 wt% IL exhibited the highest CO₂ permeability of 342.27 Barrer, while the membrane with 5 wt% IL demonstrated the best ideal selectivity for CO₂/N₂ of 27.87. At 4 bar, the membrane with 5 wt% IL showed the highest ideal selectivity for CO₂/N₂ of 40.81, with a CO₂ permeability of 144.26 Barrer. Leaching tests indicated potential integrity loss in ionic liquid composite polymer membranes at high pressures. Specifically, the CO₂ permeability of the PSF-[hmim][Tf₂N] 5 wt% membrane increased continuously post-testing due to IL leaching. However, the performance of the membranes remained stable at lower pressures (1 bar). These findings suggest that the produced membranes achieve higher permeability, CO₂/N₂ selectivity, and CO₂ diffusivity, making them suitable for post-combustion gas separation applications.

Polyethersulfone (PES) membranes have a high tendency to scale due to their inherent hydrophobicity, which limits their application and increases water treatment costs. To regulate the size of the pores of PES and prevent clogging, different qualities of poly(ethylene glycol)₃₈-block-poly(propylene glycol)₈ (PEG-PPG) were introduced and screened for the best ratios. Further introduced synthesized nitrogen-doped titanium dioxide (N-TiO₂), anti-fouling and photocatalytic PES ultrafiltration membranes (N-TiO₂@M) were prepared. N-TiO₂@M3 exhibited bovine serum albumin rejection rate of 93.8% and achieved a methylene blue photocatalytic efficiency of 95.3% after 120 min of operation. Furthermore, N-TiO₂@M4 showcased a water contact angle of 41.0°. Notably, the pure water flux of N-TiO₂@M4 surged by 499.3% compared to that of PES membrane. The fouling resistance ratio for membrane flux witnessed an increase from 70.0% to 82.7%, demonstrating the enhanced durability of N-TiO₂@M4. Moreover, the comprehensive analysis for N-TiO₂@M4 revealed a total contamination rate of 40.2%. The irreversible contamination rate of N-TiO₂@M4 after 1 h of ultraviolet light (UV) cleaning was 5.7%, and the irreversible contamination rate after 1 h of visible light irradiation was 6.7%. The method for mixing N-TiO₂ and PEG-PPG is straightforward and convenient, offering potential for the development of N-TiO₂@M with resistance to pollution and degradation in visible/UV light.

Compared to the traditional open mixing process used for the production of the rubber composites, wet mixing process is a lower shear force mixing method. This article revealed the influence of the open mixing process and the wet mixing process on the microstructure, density, mechanical properties, and ablation performance of ethylene propylene diene monomer (EPDM) rubber/fiber/hollow glass microsphere composite system. The results showed that the wet mixing process increased the fiber length by more than 300% compared to the open mixing process, while the fragmentation rate of the hollow glass beads was reduced by 94.4%, these effectively maintained the structural integrity of the fibers and the hollow glass microsphere filler. By using the wet mixing process, the density of EPDM composite materials can be reduced by about 20%, and the tensile strength and ablation resistance of these composites were also significantly improved. Compared to polyimide fiber and aramid fiber short fibers, the wet mixing process of solution-based rubber had a more significant effect on improving the length and ablation resistance of phenolic fiber and carbon fiber fibers which having poor shear strength.

This article introduces a new method in which tung oil is employed as a bio-friendly curative substance enclosed within melamine-urea-formaldehyde microcapsules. Due to the high reactivity of melamine, particle agglomeration can occur. To tackle this issue, this study focuses on optimizing the quantity of emulsifiers to achieve the best microcapsules with 15% melamine in the shell structure without particle agglomeration. The impact of melamine content and the quantity of emulsifier on the morphology of the synthesized microcapsules, the reaction yield, core content, and the hardness of the microcapsule shell were investigated. The presence of tung oil in melamine-urea-formaldehyde microcapsules was proven by Fourier transform infrared spectroscopy (FT-IR). Field emission scanning electron microscopy (FESEM) revealed the spherical morphology of the capsules with a mean diameter of 2.29 μm. UV–vis analysis and nano-indentation tests were used to evaluate the core content and the hardness of the result microcapsules, respectively. Finally, one sample, as the best microcapsule, was dispersed in an alkyd-based resin in the amount of 1, 2.5, and 5 wt% and applied on a steel substrate for its ability to prevent corrosion. The study also highlights the adverse effect of excessive capsule usage in the resin, as demonstrated by reduced resin adhesion to the substrate, according to electrochemical impedance spectroscopy (EIS) and salt spray tests. The study found that the best long-term anticorrosion properties are achieved by including 1 wt% of microcapsules in an alkyd resin.

In this paper, the foamed polylactic acid (PLA) composites with different ratios of titanium dioxide (TiO₂) and lignin (Lg) are prepared. Molecular dynamics simulation analysis indicates that the fillers enhance the mechanical properties of the composites. The optimal foaming temperatures for PLA/Lg and PLA/TiO₂ composites are found to be 110 and 100°C, respectively. The supercritical carbon dioxide foaming process is applied to get the foamed composites, and their mechanical and thermal properties are analyzed. The results show that the addition of TiO₂ improves the melting point and compression properties of the PLA composites. Furthermore, the inclusion of Lg increases the molecular chain mobility, foaming multiplicity, and compression strength of the composite materials.