M-phenylenediamine Research Articles

"Like Dissolves Like" Strategy Facilitates Interfacial Polymerization for Facile Synthesis of Highly Permeable Reverse Osmosis Membranes.

Existing reverse osmosis (RO) membranes often feature a polyamide rejection layer fabricated by interfacial polymerization (IP) between m-phenylenediamine (MPD) and trimesoyl chloride. However, polyamide RO membrane formation is limited by the poorly soluble polar MPD in the nonpolar organic solvent (e.g., hexane). Herein, we developed a dual organic solvent system to increase MPD solubility via introducing a polar solvent of dioxane into the hexane as inspired by the classical "like dissolves like" theory and thus promoting the IP reaction efficiency. Consequently, the optimal RO membrane exhibited a superior desalination performance with a rejection of 99.2% for 35,000 ppm of NaCl, simultaneous with a high water permeance of 3.1 L m-2 h-1 bar-1. Meanwhile, it had a boron rejection of 90.3% that far exceeds commercial RO membranes. These findings demonstrate that a dual organic solvent IP system can offer a facile yet effective strategy for scalable fabrication of high-performance RO membranes.

Photothermal-Assisted Interfacial Polymerization toward Microstructure Regulation of a Polyamide Membrane with Enhanced Separation Performance.

A highly permeable thin-film composite (TFC) polyamide membrane with efficient salt rejection is valuable for numerous industrial processes. To achieve this objective, it is essential to innovate the membrane fabrication process to produce an ultrathin polyamide separation layer. In this study, a photothermal-assisted interfacial polymerization (IP) strategy was proposed to fabricate TFC polyamide membranes by incorporating carboxylated carbon nanotubes (CNTs) with exceptional photothermal properties. CNTs absorb solar energy and convert it into heat, significantly elevating the temperature in their microregions, thereby accelerating the reaction between m-phenylenediamine (MPD) and trimesoyl chloride (TMC) during the IP process. Exploiting the self-inhibition characteristics of IP, the preformed polyamide layer suppresses the subsequent diffusion of MPD into the reaction interface, resulting in the formation of an ultrathin polyamide layer. Consequently, the CNTs-modified polyamide membrane with photothermal assistance obtains a thickness of approximately 94 nm, significantly thinner than the control membrane (189 nm). Furthermore, it demonstrates a superior water flux of 54.4 L m-2 h-1, higher than that of the pristine TFC membrane without CNTs and the conventional CNTs-modified membrane, while maintaining a NaCl rejection of ∼96%. The photothermal-assisted IP strategy provides some inspiration for engineering high-performance polyamide membranes available in various advanced separations.

Advanced fabrication and characterization of thin-film composite polyamide membranes for superior performance in reverse osmosis desalination

Thin film composite (TFC) polyamide membranes are crucial for efficient reverse osmosis (RO) desalination, offering high selectivity and permeability. This study investigates the fabrication and optimization of TFC membranes on polysulfone supports, focusing on their structural, morphological, and performance properties for enhanced desalination efficiency using the phase inversion technique, a method that enables precise control over membrane structure. Key fabrication parameters including the concentrations of m-phenylene diamine (MPD) and trimesoyl chloride (TMC), and the immersion times for both monomers were systematically varied to investigate their impact on membrane hydrophilicity, morphology, and structure. Hydrophilicity was assessed via contact angle measurements, Scanning electron microscopy was used to characterize the morphology (SEM), and structural properties were analyzed by Fourier-transform infrared spectroscopy (FTIR). The RO membranes’ desalination performance was evaluated by measuring water flux and salt rejection in a cross-flow setup with saline water (10,000 ppm) under controlled processing conditions. Results indicated that variations in MPD and TMC concentrations, as well as immersion times, significantly influenced membrane hydrophilicity and pore structure, affecting water flux and salt rejection. The maximum salt rejection and water flux for the prepared thin film composite reverse osmosis membrane were 98.6% and 19.1 L/m2 h, respectively obtained at m-phenylenediamine concentration of 2 wt% and tri mesoyl chloride concentration of 0.1 wt/v reacted for 1 min. The study provides insights into optimizing TFC-RO membrane fabrication parameters to enhance desalination efficiency, highlighting the potential of these membranes for high-performance RO desalination applications.

Reverse Design of High Strength and High Modulus Epoxy Resin Systems Through Computational Modeling with Experimental Validation.

High-strength and high-modulus epoxy resins are key elements for preparing carbon-fiber-reinforced polymer composites, which play an irreplaceable role in aerospace. In this study, five optimal epoxy systems were developed utilizing the reverse design strategy. The reverse design strategy was based on the ideal resin and curing agent structures offered by the AI polymer platform, and the rules were summarized to create an optimum resin formulation. The formulations used m-phenylenediamine (MPD) as the principal curing agent, which was modified with 10 wt% diethyltetramethylenediamine (DETDA), 10 wt% 4,4'-diaminodiphenylmethane (DDM), or 10 wt% triethylenetetramine (TETA) to establish multiple crosslinking networks. Systematic characterization using differential scanning calorimetry (DSC) and rheological analysis revealed that the optimized activation energy was 55.95-63.42 kJ/mol, and the processing viscosity was ≤500 mPa·s at 80 °C. A stepwise curing protocol (3 h@80 °C, 2 h@120 °C, and 3 h@180 °C) was established to achieve a complete crosslinking network. The results showed that the system with 10% DDM had a tensile strength of 132.6 MPa, a modulus of 5.0 GPa, and a glass transition temperature of 253.1 °C. This work advances the rational design of epoxy resins by bridging molecular architecture with macroscopic performance, offering a paradigm for developing a next-generation matrix tailored to accommodate extreme operational demands in high-end engineering sectors.

Nitrogen‐Doped Carbon Quantum Dot as Novel Nano Additive to Improve Performance and Fouling Resistance of Forward Osmosis Thin Film Nanocomposite Membranes

ABSTRACTForward osmosis (FO) is considered a strong and energy‐efficient desalination method. The thin film composite (TFC) membranes are widely used in the FO process. In this study, nitrogen‐doped carbon quantum dot (NCQD) was synthesized from citric acid (CA) and m‐phenylene diamine (MPD) as carbon and amine precursors, respectively, by a one‐step hydrothermal method. It was characterized completely by FT‐IR, XRD, UV–visible spectroscopy, DLS, and TEM analysis. Then, NCQD was incorporated in the polyamide (PA) layer to synthesize novel thin film nanocomposite (TFN) membranes. All membranes were analyzed by FT‐IR, WCA, AFM, and FE‐SEM. The TFN‐NCQD membrane, optimized with a concentration of 2000 ppm NCQD, exhibited outstanding FO performance, achieving a 70% increase in water flux compared to the pristine TFC. This membrane attained a peak water flux of 20.4 LMH, a reverse salt flux of 2.1 gMH, and showcased the best selectivity, with values as low as 0.10 g/L among the others. The strong interaction between amine functional groups of NCQD with both MPD and TMC during interfacial polymerization resulted in excellent adhesion and compatibility between the nanofiller and PA, increasing the lifespan of TFN membranes. Moreover, the novel TFN‐NCQD2 membrane showed better fouling behavior than pristine TFC, a 22% improvement when sodium alginate solution (600 ppm) was used as a foulant model.

High‐Flux Thin Film Composite Membranes Prepared by Interfacial Polymerization With Pyridine or Pyrimidine Structured Diamines as Aqueous Phase Monomers for Efficient Organic Solvent Nanofiltration

ABSTRACTHerein, a series of high‐flux thin film composite organic solvent nanofiltration (TFC OSN) membranes were prepared using diamine monomers with pyridine or pyrimidine structures (2,6‐Diaminopyridine (Pd), 4,6‐Diaminopyrimidine (Pm)) alternatively to M‐phenylenediamine (MPD) via interfacial polymerization (IP). Compared to MPD, Pd and Pm have a different number of electron‐donating N atoms in the six‐membered ring skeleton. As nucleophilic reagents, the presence of N atoms affects the chemical composition, structure, and cross‐linkage degree of the polyamide active layers formed by their A2‐B3 type nucleophilic substitution reactions. The results show that the membranes prepared with Pd or Pm have higher permeability to solvent than the membrane prepared with MPD. The solvent flux of the TFC‐Pd membrane (19.12 L m−2 h−1 bar−1) and TFC‐Pm membrane (12.35 L m−2 h−1 bar−1) was 2.30 and 1.49 times that of the TFC membrane (8.32 L m−2 h−1 bar−1), respectively. Meanwhile, the rejection of EB dye by the TFC‐Pd and TFC‐Pm membranes was more than 90%. Furthermore, the prepared TFC‐Pd and TFC‐Pm membranes all showed good organic solvent resistance and long‐term operation even after immersion in strong polar N, N‐Dimethylformamide at 60°C for 6 days, indicating that the high‐flux OSN membranes prepared with Pd or Pm monomers have good long‐term stability.

Preparation of Crown Ether-Containing Polyamide Membranes via Interfacial Polymerization and Their Desalination Performance.

The large-scale application of aromatic polyamide (PA) thin-film composite (TFC) membranes for reverse osmosis has provided an effective way to address worldwide water scarcity. However, the water permeability and salt rejection capabilities of the PA membrane remain limited. In this work, cyclic micropores based on crown ether were introduced into the PA layer using a layer-by-layer interfacial polymerization (LbL-IP) method. After interfacial polymerization between m-phenylenediamine (MPD) and trimesoyl chloride (TMC), the di(aminobenzo)-18-crown-6 (DAB18C6) solution in methanol was poured on the membrane to react with the residual TMC. The cyclic micropores of DAB18C6 provided the membrane with rapid water transport channels and improved ion rejection due to its hydrophilicity and size sieving effect. The membranes were characterized by FTIR, XPS, SEM, and AFM. Compared to unmodified membranes, the water contact angle decreased from 54.1° to 31.6° indicating better hydrophilicity. Moreover, the crown ether-modified membrane exhibited both higher permeability and enhanced rejection performance. The permeability of the crown ether-modified membrane was more than ten times higher than unmodified membranes with a rejection above 95% for Na2SO4, MgSO4, MgCl2, and NaCl solution. These results highlight the potential of this straightforward surface grafting strategy and the modified membranes for advanced water treatment technologies, particularly in addressing seawater desalination challenges.

Study on the properties of biomass carbon quantum dots modified with diamine compounds and their application in iron ion detection

Diamine compounds are widely used as surface modifiers in the functionalization of carbon quantum dots, yet the effects of different diamines on the properties of carbon quantum dots remain unclear. In this study, carbon dots (P-CDs) were synthesized from peanut shell powder via a simple one-step microwave-assisted hydrothermal method. The surface of these carbon dots was modified through co-heating with ethylenediamine (EDA), o-phenylenediamine (OPD), m-phenylenediamine (MPD), and p-phenylenediamine (PPD). The effects of different diamines on the morphology and optical properties of P-CDs were systematically analyzed. The diamine-modified P-CDs exhibited varying sizes and similar crystal structures, with significantly enhanced fluorescence and quantum yields, reaching 35.2% for EDA-CDs. EDA-CDs and OPD-CDs demonstrated excitation-dependent emission behavior, while MPD-CDs and PPD-CDs did not. Based on EDA-CDs, a probe with high sensitivity for Fe3+ was developed, showing a good linear response within the Fe3+ concentration range of 20–100 μM and a detection limit of 2.768 μM. Additionally, the ion probe exhibited a recovery rate of 100.85% in both deionized and tap water, indicating good practical applicability. This study provides essential guidance for the nitrogen surface modification of biomass-derived carbon quantum dots and presents a promising Fe3+ probe with potential applications.

Synthesis of polyamide-based RO membranes for saline water treatment

Reverse osmosis (RO) technology is a widely used method for converting seawater into fresh water, known for its high efficiency and broad applications. This study focuses on optimizing the synthesis conditions for polyamide (PA) membranes, including the concentrations of m-phenylenediamine (MPD) and trimesoyl chloride (TMC), the choice of solvent, soaking time, and reaction time. FTIR and SEM analysis confirmed the successful synthesis of the PA layer and revealed that the surface morphology of the membrane was significantly influenced by synthesis conditions. Mechanical testing demonstrated that the optimized membranes exhibited high tensile strength (41.18 MPa) and low elongation at break (11.69%), indicating a robust but relatively brittle material. The study determined that the optimal conditions were 1.0 wt.% MPD and 0.1 wt.% TMC, hexane as a solvent, a soaking time of 2 min, and a reaction time of 60 sec, achieving a maximum salt rejection of 86.45%. These findings are critical for enhancing RO membrane efficiency and addressing the global demand for clean water.

STUDY OF FOULING AND MASS TRANSFER PROPERTIES OF CELLULOSE ACETATE-MODIFIED TFC MEMBRANES

The main objective of this work was to study the performance of thin-film composite (TFC) membranes developed for the treatment of saltwater. The synthesis of TFC polymer membranes was successfully achieved through interfacial polymerization between m-phenylenediamine (MPD) and trimesoyl chloride (TMC) on a 150 μm thick polyethersulfone (PES) support. The permeability and selectivity of the TFC membranes were investigated by incorporating cellulose acetate (CA) at various concentrations in an aqueous solution of MPD. The physicochemical properties of the prepared membranes were analyzed using FTIR, as well as in terms of water content and mass transfer characteristics. The optimized TFC membrane (TFC3; MPD: 2% by weight, CA: 5.7% by weight) exhibited improved efficiency in rejecting NaCl, CaCO3, and MgSO4, with respective rejection rates of 59.81%, 52.24%, and 62.53%, and a flux of 98 L/m².h. The flux recovery rate of this membrane was higher than that of the standard TFC membrane, indicating better resistance to fouling.

Enhancing the Viability of Zinc-Polyiodide Flow Batteries: A Study on Innovative Composite Polyamide-Porous Separators for Optimized Ionic Conductivity and Ion Permeability

Zinc-polyiodide flow batteries (ZIFBs) are recognized for their superior theoretical energy capacity and are considered prominent energy storage devices. The viability of ZIFBs relies on the development of cost-effective separators demonstrating excellent ionic conductivity and selective ion permeability. In this study, an economical polymer blend comprising poly(ether sulfone) (PES) and sulfonated poly(ether ether ketone) (sPEEK) was fabricated using a phase inversion technique. The resulting sponge-like structure of the porous substrate exhibits high ionic conductivity. Additionally, the selected porous substrate was topped with a thin-film polyamide synthesized from m-phenylenediamine (MPD) and 1,3,5-benzene tricarbonyl trichloride (TMC) through interfacial polymerization (IP). This polyamide layer effectively mitigates undesired triiodide ion migration while maintaining high ionic conductivity. The innovative approach allows for a composite separator with a finely tunable structure. Employing such a separator enables ZIFBs to operate stably with a high coulombic efficiency (CE) of 91% over 100 cycles at a current density of 10 mAh cm-2. This study explores the trade-off between ionic conductivity and ion permeability, demonstrating that adjusting the morphology of composite separators enhances their physical characteristics, ensuring the stable and efficient operation of ZIFBs.

Interfacial Polymerization of Aromatic Polyamide Reverse Osmosis Membranes.

Polyamide membranes are widely used in reverse osmosis (RO) water treatment, yet the mechanism of interfacial polymerization during membrane formation is not fully understood. In this work, we perform atomistic molecular dynamics simulations to explore the cross-linking of trimesoyl chloride (TMC) and m-phenylenediamine (MPD) monomers at the aqueous-organic interface. Our studies show that the solution interface provides a function of "concentration and dispersion" of monomers for cross-linking. The process starts with rapid cross-linking, followed by slower kinetics. Initially, amphiphilic MPD monomers diffuse in water and accumulate at the solution interface to interact with TMC monomers from the organic phase. As cross-linking progresses, a precross-linked thin film forms, reducing monomer diffusion and reaction rates. However, the structural flexibility of the amphiphilic film, influenced by interfacial fluctuations and mixed interactions with water and the organic solvent at the solution interface, promotes further cross-linking. The solubility of MPD and TMC monomers in different organic solvents (cyclohexane versus n-hexane) affects the cross-linking rate and surface homogeneity, leading to slight variations in the structure and size distribution of subnanopores. Our study of the interfacial polymerization process in explicit solvents is essential for understanding membrane formation in various solvents, which will be crucial for optimal polyamide membrane design.

High rejection seawater reverse osmosis TFC membranes with a polyamide-polysulfonamide interpenetrated functional layer

High rejection seawater reverse osmosis TFC membranes with a polyamide-polysulfonamide interpenetrated functional layer

Mussel-inspired co-deposition of catechol-amine and graphene oxide (GO) modified anion exchange membranes (AEMs) for antifouling

Mussel-inspired co-deposition of catechol-amine and graphene oxide (GO) modified anion exchange membranes (AEMs) for antifouling

Dual optimization strategy assisted m-phenylenediamine-based hypercrosslinked polymer loaded ultrafine bimetallic nanoparticles for efficient formic acid dehydrogenation

Dual optimization strategy assisted m-phenylenediamine-based hypercrosslinked polymer loaded ultrafine bimetallic nanoparticles for efficient formic acid dehydrogenation

Catechol/m-Phenylenediamine Modified Sol-Gel Coating with Enhanced Long-Lasting Anticorrosion Performance on 3003 Al Alloy.

Aluminum alloys, characterized by their low density and high mechanical strength, are widely applied in the manufacturing sector. However, the application of aluminum alloys in extreme environments presents severe corrosion challenges. Sol-gel organic coating techniques have garnered significant attention due to their excellent stability, barrier properties, and cost-effectiveness, as well as their simpler processing. Nevertheless, conventional sol-gel coatings are unable to withstand the corrosive effects of high-chloride and high-halide ion environments such as marine conditions, owing to their inherent structural defects. Therefore, this study proposes the utilization of a simple method to synthesize catechol (CA) and meta-phenylenediamine (MPD)-derived catecholamine compounds to modify sol-gel coatings. Surface characteristics of the modified coatings were analyzed using Fourier-transform infrared spectroscopy (FT-IR), ultraviolet-visible (UV-Vis) spectroscopy, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The thickness of the modified coating was approximately 6.8 μm. The CA/MPD-modified substance effectively densifies the sol-gel coating, enhancing its corrosion protection performance. A 3.5 wt% NaCl solution was used to simulate a marine environment, and electrochemical impedance spectroscopy (EIS) was conducted using an electrochemical workstation to evaluate the coating's protective properties over a long-term period. The results indicate that the modified coating provides protection for 3003 aluminum alloy for a minimum of 30 days under corrosive conditions, outperforming unmodified sol-gel coatings in terms of corrosion resistance.

Development of Polyamide-Modified Membranes for Solar-Driven Seawater Desalination System

In response to the escalating global water crisis, this study introduces the development of polyamide-modified membranes (PA-PES, PA-PP, and PA-PTFE) through interfacial polymerization to enhance the efficiency of a passive solar desalination system. FTIR analysis and morphological characterization showed that a thin polyamide film formed above the modified membranes using m-phenylene diamine (MPD) and trimesoyl chloride (TMC). Notable improvements were observed in its productivity and distillate salinity by integrating these modified membranes into the membrane distiller of the system. Mainly, the PA-PES membrane achieved productivity of 764.56 ml/m2-h and reduced salinity to as low as 2 g NaCl/L. Despite challenges in salinity reduction, possibly due to residual chlorides, this study demonstrates the potential of polyamide-modified membranes in advancing solar-driven desalination, offering a promising solution to mitigate global water scarcity. This research paves the way for further advancements in sustainable desalination technology, emphasizing the need for continued optimization and exploration of membrane-based systems.

Interfacial oligomer splicing toward 3D silicon-centered polyimine nanofilm for rapid molecule/ion differentiation

Interfacial oligomer splicing toward 3D silicon-centered polyimine nanofilm for rapid molecule/ion differentiation

Ni(II)/Yb(III)-metallogels for distinctive fluorescent ‘turn-on’ detection of m-phenylenediamine: Toward construction of multiple logic gates

Ni(II)/Yb(III)-metallogels for distinctive fluorescent ‘turn-on’ detection of m-phenylenediamine: Toward construction of multiple logic gates

Synthesis and characterization of linear hybrid aliphatic/aromatic copolyurea via one‐step feeding method

AbstractThe combination of aromatic and aliphatic structures can endow polyurea with distinct performance advantages. A one‐step feeding method is used to synthesize linear hybrid aliphatic/aromatic copolyureas by varying the ratio of m‐phenylenediamine (MPD) and polyoxypropylenediamine (D2000) reacting with 4,4′‐diphenylmethane diisocyanate (MDI). Real‐time Fourier‐transform infrared spectrometer monitoring reveals that D2000 exhibits higher reactivity than MPD. Consequently, in the MDI/MPD/D2000 system, D2000 initially reacts with MDI to form an isocyanate‐terminated prepolymer, which subsequently reacts with MPD. Compared with the two‐step feeding method, this approach successfully eliminates biuret formation and enhances tensile strength. Additionally, decreasing the molar ratio of D2000 to MPD (λm) reduces the size and degree of microphase separation in the polyurea by increasing the ordered hydrogen bonding and benzene conjugation, leading to an increase in tensile strength. Specifically, as λm decreases from 70 mol% to 30 mol%, the degree of microphase separation decreases from 0.47 to 0.2, causing the tensile strength to rise from 28 to 48 MPa. Further reducing λm to 30 mol% decreases the degree of microphase separation to 0.16, resulting in an increase in tensile strength to 78 MPa.