Excellent Solvent Research Articles

Pentagon-embedded N-doped coumarinacenes: tandem synthesis and tunable photophysical attributes for biomolecular probing.

We have synthesized a novel series of nitrogen-doped pentagon-embedded coumarinacenes, namely carbazole-coumarins, via a tandem 1,4-elimination Diels-Alder aromatization reaction. These planar, N-substituted carbazole-coumarins exhibit excellent functionalizability, enhanced photostability and solvent polarity-tunable absorption and blue-to-red emission with notably high fluorescence quantum yields, attesting to their remarkable photophysical properties. These attributes highlight the carbazole-coumarins' potential as robust and efficient fluorescent materials for diverse applications in various fields, including as probes for studying biomolecular systems and dynamics.

Design and Study of Azobenzene‐Modified AESO Photopolymerization Coating for Information Reversible Storage Performance

ABSTRACTThe photo‐induced cis‐trans isomerization of azobenzene molecules, known for their significant color changes, is extensively utilized in the functional modification of polymeric materials. However, the research on the functionalization of biomass‐based polyesters with azobenzene is limited. A key raw material for biomass‐based coatings possess reactive double bonds and excellent film‐forming capabilities, offering significant advantages for azobenzene functionalization in biomass‐based polyester applications. In this study, AESO served as the polyester matrix and acrylate azobenzene derivatives as the functional molecules. Under ultraviolet radiation, AESO underwent a carbon–carbon crosslinking reaction with the azobenzene derivatives to synthesize a novel resin. The coating of this resin on a PET substrate exhibited excellent pencil hardness (3B), adhesion (5B), and solvent resistance. By alternating exposure to ultraviolet and blue light, the coating displayed reversible switching between cis and trans isomers, enabling reversible writing and erasing of patterns. Even after 20 cycles of writing and erasing, high‐resolution patterns could still be observed (clearly visible under a 12x microscope). Furthermore, the image could be retained for up to 2 h under sunlight irradiation. This study presents a new method for functionalizing biobased polyesters.

Advanced PPS/MOFs composite nanofiltration membranes derived from contra-diffusion synthesis for precise molecular separation

To meet the separation requirements of polyphenylene sulfide (PPS) membranes in extremely harsh environments and to enhance the separation performance of PPS membrane material, this study utilizes Zeolitic imidazolate framework (ZIF) material with a porous structure to modify the structure of the PPS membranes. Using the Contra-diffusion synthesis method, we successfully created PPS composite membranes that were modified by ZIF-8. At the end of the three-hour reaction time, a continuous and dense layer of ZIF-8 crystals with uniform crystal size and regular crystal shape was produced on the matrix membrane's surface. The permeance to rhodamine B aqueous solution is 42.54 L m−2 h−1 bar−1, and the retention rate is 99.5 %, which has high permeability and retention performance. In the anti-pollution performance test, the composite membrane's flux recovery rate is 72.9 %, which has good anti-pollution performance. After immersion in strong acids, strong alkalis, and a variety of organic solvents, the appearance shows no evident flaws, and the separation performance in strong alkalis and five different types of organic solvents stays steady, demonstrating excellent alkali and solvent resistance. This proves that composite membranes have great potential for application in dye wastewater treatment.

Efficient fabrication of chitin-based films with high UV-blocking and fluorescence via Hantzsch reaction

As the second most abundant polysaccharide on earth, chitin-based films are promising packaging and biomedical materials. However, the lack of special function (especially UV-blocking properties and fluorescence) usually restricts their further and high-value applications. Herein, high UV-blocking and fluorescence chitin-based films were fabricated via surface modification using acetoacetation and the Hantzsch reaction. The structure and properties of the films were characterized by NMR, FTIR, fluorescence spectrum, and tensile tests. The results showed that the benzene ring and 1,4-dihydropyridine ring (DHP) were successfully grafted on the films in the mild process. Besides, the degree of substitution of DHP (DSDHP) increased with the reaction time, temperature, and substrate concentration. Moreover, the modification followed a first-order reaction at 20 °C with a rate constant of 2.1 × 10−4. When the DSDHP was over 0.029, the films exhibited 100 % UV shielding. The fluorescence spectrum demonstrated that the films had excellent solvent and temperature resistance. In addition, the films exhibited excellent mechanical strength with tensile strength up to 85.2 MPa. This work provides a facile and environmentally friendly strategy to fabricate a functional chitin-based film with potential applications in UV protection, medical packaging, and fluorescent materials.

Controlled Sensor Derived from COF Materials for the Effective Detection of N-Methylpyrrolidone.

N-methylpyrrolidone (NMP) is an excellent advanced solvent that can be easily absorbed by the human body and has the characteristics of flammability and explosion. To reduce the risk, the environmental concentrations of NMP need to be measured. A series of covalent organic frameworks (COF) connected by an imine bond have been successfully prepared at room temperature by changing the synthesis time catalyzed by scandium(III) trifluoromethanesulfonate (Sc(OTf)3). The effect of the synthesis time on the sample properties was compared by XRD, FT-IR, XPS, SEM, TEM, and BET. The results showed that synthesis time had almost no effect on the morphology, specific surface area, and functional groups of the COF samples but had a significant impact on the pore size distribution, residual bonds, and other defects, which in turn affected the gas sensing performance. The sensor results showed that all samples had good sensing performance for NMP, among which the sample synthesized for 48 h had the best sensing performance, with a limit of detection of 692 ppb and good stability and repeatability. The excellent performance of the COF samples benefits from the large specific surface area, hydrogen bonding interactions, electrostatic attraction, and high defects. This study provides an effective method for NMP detection and expands the application range of the COF materials.

Extraction and Counter-Current Separation of Phenylpropanoid Glycosides from Pedicularis oederi Vahl by Deep Eutectic Solvent

Deep eutectic solvents (DESs) are mixtures of organic compounds displaying excellent solvent properties while keeping an ecofriendly character. In this study, DESs have been applied to the extraction of phenylpropanoid glycosides from Pedicularis oederi Vahl, successively separated by means of counter-current chromatography. Firstly, the ultrasonic-assisted extraction conditions were optimized by response surface methodology, and the results showed phenylpropanoid glycosides could be well extracted under the optimized extraction conditions with deep eutectic solvents. Then, the sample was separated by counter-current chromatography using ethyl acetate/aqueous solution of choline chloride and glycerol (6:6, v/v) as the solvent system. In about 360 min, four phenylpropanoid glycosides, including 31.6 mg of echinacoside, 65.3 mg of Jionoside A1, 28.9 mg of Forsythoside B, 74.1 mg of verbascoside, and 21.2 mg of kaempferol-3-O-rutinoside were obtained from about 900 mg of the sample. It revealed deep eutectic solvents could be well employed as a green solvent for the extraction and counter-current separation of natural products.

Healable, Recyclable, and Ultra-Tough Waterborne Polyurethane Elastomer Achieved through High-Density Hydrogen Bonding Cross-Linking Strategy.

With the increasing popularity of elastomers in industry and daily life, their high performance and functionality have attracted widespread attention. However, it is a great challenge for them to possess both high mechanical properties and excellent healing and recovery capabilities due to the limitations of the preparation methods and the intrinsic microstructure of the elastomers. In this study, a strategy of ice-controlled interfacial stepwise cross-linking was proposed to prepare the waterborne polyurethane-based elastomers with ultrahigh-density hydrogen bonding interaction achieved by enhancing the utilization rate of phenol hydroxyl groups of tannic acid to the maximum extent. The elastomers have incredible mechanical properties, including ultrahigh toughness of 1.03 GJ m-3 (which represents the highest level among polyurethane elastomers prepared through common processing techniques to date), extremely high true fracture stress of ∼1.9 GPa, world-record fracture energy of 520 kJ m-2, and exciting multiple functional characteristics, such as highly efficient self-healing ability of 10 min, high resistance to physical damage and chemical corrosion, broad temperature and frequency damping effects, good shape memory effect, and excellent melt-processing recyclability and solvent recyclability. These robust multifunctional elastomers represent considerable potential in various fields, from defense and military industry and civil transportation to precision manufacturing, etc.

The Influence of Carbon Fiber on Crystallization and Morphology of Poly(Ether Ketone Ketone) Composites Towards High Rate Thermoplastic Manufacturing Processes

Recent interest in thermoplastic composites for aerospace applications is driven by the need for high-volume manufacturing of materials that display excellent mechanical, thermal, and solvent resistive properties. Specifically, a large component of the composite properties of thermoplastic composites are highly dependent on the crystalline fraction of the semi-crystalline polymer matrix of the reinforced system. This work investigates the melting behavior of poly (ether ketone ketone) (PEKK) and the influence of temperature and fiber on crystallization kinetics and morphology of (PEKK) composites utilizing, differential scanning calorimetry, Velaris-Sefaris modelling, and polarized optical microscopy (POM). Annealing temperatures of 380°C and above were required to fully erase crystalline ordering in the PEKK matrix. Furthermore, carbon fibers accelerated crystallization kinetics in PEKK at a range of temperatures observed via DSC, and Velaris-Sefaris modelling implied a shift from bulk to surface induced nucleation by the addition carbon fiber to the PEKK matrix, reducing activation energy of crystallization events. This nucleation behavior was visually confirmed through POM with observation of transcrystalline domains nucleated from the surface of a single carbon fiber.

The Influence of Carbon Fiber on Crystallization and Morphology of Poly(Ether Ketone Ketone) Composites Towards High Rate Thermoplastic Manufacturing Processes

Recent interest in thermoplastic composites for aerospace applications is driven by the need for high-volume manufacturing of materials that display excellent mechanical, thermal, and solvent resistive properties. Specifically, a large component of the composite properties of thermoplastic composites are highly dependent on the crystalline fraction of the semi-crystalline polymer matrix of the reinforced system. This work investigates the melting behavior of poly (ether ketone ketone) (PEKK) and the influence of temperature and fiber on crystallization kinetics and morphology of (PEKK) composites utilizing, differential scanning calorimetry, Velaris-Sefaris modelling, and polarized optical microscopy (POM). Annealing temperatures of 380°C and above were required to fully erase crystalline ordering in the PEKK matrix. Furthermore, carbon fibers accelerated crystallization kinetics in PEKK at a range of temperatures observed via DSC, and Velaris-Sefaris modelling implied a shift from bulk to surface induced nucleation by the addition carbon fiber to the PEKK matrix, reducing activation energy of crystallization events. This nucleation behavior was visually confirmed through POM with observation of transcrystalline domains nucleated from the surface of a single carbon fiber.

Screening of the biphenyl polyamides nanofilms appropriate for molecular separation in organic solution feed

Developing polymeric separation membranes that combine excellent solvent stability, high permeability, and customizable molecular weight interception remains a challenge. Herein, thin-film composite (TFC) polyamide (PA) membranes with poly(ether ether ketone) (PEEK) support and biphenyl-centered polyamides active layer were fabricated through interfacial polymerization technique for the first time. Enhanced solvent stability was exhibited by the fabricated membranes due to the intrinsic resistance to organic solvents possessed by PEEK and biphenyl polyamides. The separation performance of the obtained membranes was systematically studied by relating to the properties of PA nanofilms in terms of nano-mechanical strength, morphologies, and microporosity. The organic solvent nanofiltration (OSN) performance of the resultant membranes in terms of permeability and molecular weight cut-off (MWCO) could be regulated. The optimized membrane exhibited a pure solvent permeability as high as 21.6 L m−2 h−1 bar−1 for acetonitrile and 14.0 L m−2 h−1 bar−1 for methanol. It also showed excellent long-term durability with almost unchanged permeability as well as solute retention remained above 97.8 % after a cumulative OSN operation of N, N-Dimethylformamide (DMF) based feed for 240 h. In particular, OSN membrane with targeted MWCOs covering the range of 170–370 g·mol−1 could be fabricated by selecting appropriate biphenyl acyl chlorides as building blocks. This approach offers a scalable and versatile platform for the development of solvent-stable, highly permeable, and customizable MWCO membranes for process-oriented OSN.

Sustainable strategy for lignin etherification and its promotion of anti-UV aging PLA biocomposite

Achieving efficient modification of both phenolic (Phe)-OH and aliphatic (Aliph)-OH groups in lignin simultaneously via sustainable method, remained a significant challenge. In this study, a series of highly hydroxyl-substituted alkali lignin phenyl propylene ketone ethers (ALK) were obtained under 50 °C without any by-products via the mild and sustainable hydroxyl-yne click reaction method. Notably, phenolic (Phe)-OH content of lignin decreased from 4.12 mmol g−1 to 0.07 mmol g−1 with a conversion rate of 98 %, while the aliphatic (Aliph)-OH content of lignin decreased from 2.57 mmol g−1 to 0.10 mmol g−1 with a conversion rate of 96 %. Owing to the efficient etherification, ALK showed excellent organic solvent (such as trichloromethane, DCM, THF, and acetone) solubility, which thereby improving the interfacial compatibility between ALK and PLA matrix. 3 wt% ALK obviously enhanced the mechanical properties of ALK/PLA biocomposite films, with the yield strength, breaking strength, and Young’s modulus improving by 114.2 %, 30.7 % and 250.2 %, respectively. Additionally, due to the newly introduced vinyl ether bonds (−C–O–CC–) in ALK by hydroxyl-yne click reaction, only 1 % ALK could endow ALK/PLA biocomposite with excellent UV shielding (100 %), high transmittance (84.3 %) and Anti-UV aging property. The yield strength and Young’s modulus represented an increase of 209 % and 86 %, respectively, even after 3 h of UV-irradiation. This study presents an environmentally friendly lignin functionalization method that unleashes the inherent Anti-UV aging properties of lignin, opening new avenues for the development of high-performance lignin-based composites.

Ultrasonic assisted electrospinning preparation the polylactic acid loading with perillaldehyde biopolymer film with excellent solvent resistance, water-oxygen barrierstability and preservation effect

The aim of this study was to optimize the concentration of polylactic acid (PLA) as the film matrix, perilla aldehyde (PAE) as the antibacterial-agent, and Amino-PEG7-amine as the coupling agent to prepare nanofiber films with a stable structure and excellent preservation. This optimization was achieved by varying the addition concentration of PLA (0.25, 0.5, 1.0, and 2.0 g/mL) and ultrasonic-assisted film-forming power (320 W, 480 W, 640 W, and 800 W). The results of process optimization demonstrate the nanofiber filaments in the 1.0 g/mL PLA film exhibit uniformity and absence of beads, and 640 W ultrasonic power results in a decrease in the diameter of nanofiber filaments and improves their uniformity. Infrared spectrum analysis, differential scanning calorimetry, and X-ray diffraction results indicate that the application of 640 W ultrasonic power promoted cross-linking polymerization between PLA and PAE, resulting in a nanofiber film with improved thermal stability. The PLA@PAE-640 film exhibits exceptional barrier properties against water vapor. The preservation experiment reveal that incorporating ultrasonic assistance at 640 W is particularly advantageous in prolonging the release of PAE active substance and enhancing the preservation effect. Therefore, integrating ultrasonic assistance proves to be an effective approach for improving film performance and achieving controlled release.

Hollow microporous organic network fiber membrane for efficient extraction of okadaic acid from marine organisms

Membrane-based micro-solid phase extraction (M-μSPE) has garnered great attention in sample pretreatment, suffering an inherent contradiction between permeability and adsorption capacity. In this study, a pure microporous organic network (TEB-DIB-MON) fiber membrane was prepared by combining electrostatic spinning technology, Sonogashira-Hagihara reaction and template sacrifice method. The prepared TEB-DIB-MON membrane exhibited a large specific surface area with a hollow and porous structure, thereby providing excellent solvent permeability and high adsorption capacity for okadaic acid (OA, an algal toxin). Under the optimized conditions, a sensitive analytical method was established by coupling M-μSPE with high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The established method has a low detection limit (0.5 pg mL−1), a wide linear range (1.5–1000 pg mL−1, R ≥ 0.9991), and good reproducibility (RSD ≤ 9.4 %, n = 6), which was then successfully applied for OA detection in marine organisms. Trace amounts of OA (59.3–89.0 pg mL−1) was detected in the oyster and prawn samples. This work demonstrated that the excellent application potential of MON membranes in sample pretreatment, while also presents a novel synthesis strategy for MONs membranes.

Modification of an AIE Fluorescent Probe for Monitoring the Polarity of Lipid Droplets Based on a Series of Synthesized Aryl Naphthalizes.

Lipid droplets (LDs) are subcellular organelles that are dynamic and play a central role in energy homeostasis and lipid metabolism. They also contribute to the transport and maturation of cellular proteins and are closely associated with several diseases. The important role of the cellular microenvironment in maintaining cellular homeostasis. Changes in cell polarity, particularly in organelles, have been found to be strongly linked to inflammation, Alzheimer's disease, cancer, and other illnesses. It is essential to check the polarity of the LDs. A series of arylated naphthalimide derivatives were synthesized using the Suzuki reaction. Modification of synthesized aryl naphthalimides using oligomeric PEG based on intramolecular charge transfer (ICT) mechanism. A series of fluorescent probes were designed to target LDs and detect their polarity. Nap-TPA-PEG3 probe exhibited high sensitivity to polarity. The addition of oligomeric polyethylene glycol (PEG) to the probe not only significantly improved its solubility in water, but also effectively reduced its cytotoxicity. In addition, the probe exhibited excellent aggregation-induced luminescence (AIE) properties and solvent discolouration effects. Nap-TPA-PEG3 probe exhibited high Pearson correlation coefficient (0.957163) in lipid droplet co-localization in cells. Nap-TPA-PEG3 could be used as an effective hand tool to monitor cell polarity.

Dynamic imine crosslinking for waterproof starch plastic with tunable mechanical properties

Starch-based plastics offer a potential solution to environmental pollution and can reduce the dependence on petroleum-based plastics. However, effectively preparing starch-based plastics with moisture resistance and high strength remains challenging. Herein, dialdehyde starch (DAS) with different degrees of oxidation was first synthesised. The molecular weight and crystallinity of DAS decreased depending on the aldehyde content, as determined through scanning electron microscopy, X-ray diffraction and molecular weight analyses. Subsequently, a sustainable starch plastic (DAS-DA) was prepared via the dynamic imine crosslinking of DAS with diamines. The influence of the degree of oxidation of DAS on the structure and properties of DAS-DA was systematically investigated. No linear relationship was observed between the tensile strength of DAS-DA and the aldehyde content of DAS. When the aldehyde content was 41.1 %, the resulting DAS41-DA exhibited optimal mechanical strength (27.8 MPa), exceeding that of most reported starch-based plastics. In addition, owing to the presence of imine crosslinking networks, DAS41-DA exhibited excellent water and solvent resistance (>60 days), good thermal stability (456 °C–462 °C) and excellent reprocessability and biodegradability. These findings provide a theoretical basis for the preparation of high-performance bioplastics from aldehyde-containing polysaccharides.

Enhancement of thermo-oxidative stability of polyimide composites by functionalized polyimide film surface modification

Polyimide (PI) resin-based composites exhibit excellent high-temperature resistance, solvent resistance, and mechanical properties, making them have broad application prospects in various fields such as aviation, aerospace, and transportation. With the continuous development of new devices, the requirements for the service temperature and service life of materials are improved, so there is an urgent need to improve the thermo-oxidative stability of polyimide composites. In this work, PI films, aluminum-coated PI film, and copper-coated PI film with low oxygen permeability were used as surface oxygen barrier materials, and surface film modified polyimide composites were prepared. The results show that, compared with the unmodified composite materials, after aging at 350°C for 400 hours, the weight loss rates of the composites modified by three kinds of surface films all increased by more than 50%, and the bending strength retention rates of the composites respectively increased by 47%, 51%, 45%, and the interlaminar shear strength retention rates respectively increased by 107%, 82%, 78%, showing excellent thermo-oxidative stability.

A new strategy applying ternary blends of modified natural rubber with fluoroplastic and fluorocarbon elastomer for high-performance thermoplastic vulcanizate

High-performance thermoplastic vulcanizates (TPVs) are a class of specialty polymers with exceptional mechanical properties, rubber-like elasticity, excellent processability and recyclability, and an excellent price-performance ratio that make them ideal for a variety of industrial applications. In this work, a successful method of creating high-performance TPV using a ternary blend of poly(methyl methacrylate) modified natural rubber (MGNR), poly(vinylidene fluoride) (PVDF), and fluorocarbon elastomer (FKM) was employed. Combining NR known for its exceptional rubber elasticity and resilience, with fluoropolymers, known for their exceptional chemical resistance and thermal stability, resulted in materials with a synergistic blend of properties. The developed PVDF/FKM/MGNR blend showed higher elasticity, tensile strength, and elongation at break than PVDF/FKM and PVDF/MGNR blends because the ternary blend had greatly improved phase morphology and compatibility between the three phases. The domain size in the ternary blend was smaller than 150 nm. The ternary blends also exhibited excellent thermal properties, where melting and crystallization temperatures were reduced significantly with MGNR due to possible dipole-dipole interactions. At the same time, the oil resistance and shape memory behavior of PVDF/FKM/MGNR were improved at an appropriate blend ratio. The ternary TPVs demonstrated good shape fixities (90–100 %) and shape recoveries (70–80 %). This research offers valuable insights into the design of high-performance thermoplastic elastomers based on natural rubber, which have excellent mechanical properties, solvent resistance, and potential for intelligent and lightweight application.

Sustainable poly(imide‐imide) vitrimer based on multiple dynamic covalent bonds

AbstractPolyimide materials with high mechanical strength are widely used in various fields, but pose certain challenges in achieving sustainable material utilization. A poly(imide‐imide) vitrimer material (ADTA) based on multiple dynamic covalent bonds (imide, imine, and disulfide bonds) was constructed by preparing vanillin difunctionalized derivatives (DVA) for aldolamine condensation reactions with bis‐amine monomers (ATFA) and tris(2‐aminoethyl) amines (TAEA) with imide structures. The ADTA material has good 5% thermal stability Td5% (278.87°C), high energy storage modulus E (2421.26 MPa), and fast relaxation time (36.39 s). The thermal stability and mechanical properties of the material are enhanced by the more stable alicyclic structure of the imide structure. The material also demonstrated excellent solvent resistance and self‐healing properties. This study provides a new option for the development of sustainable utilization of polyimide materials.

Simulation of extractive distillation of C6 components from Fischer‐Tropsch Synthesis oil

AbstractExtractive distillation is used for separating oxygenates from other components in the C6 cut oil from Fischer‐Tropsch Synthesis followed by separating 1‐hexene from N‐hexane using the same solvent as the extractant. Furfural (FUR) is identified as an excellent solvent for extractive distillation of the C6 cut from FTS oil for separating oxygenates from other components as well as for separating 1‐hexene from N‐hexane via searching from more than 100 solvents by simulation using Aspen Plus. The behavior of the newly found solvent FUR is compared with that of the reported best solvent N‐methyl‐2‐pyrrolidone (NMP) and the results show that FUR scheme has the advantages of lower market price, lower dosage needed, less reboiler duty required and higher overall tray efficiency for fulfilling the same separation task.

Sustainable Plastics with High Performance and Convenient Processibility.

Designing and making sustainable plastics is especially urgent to reduce their ecological and environmental impacts. However, it remains challenging to construct plastics with simultaneous high sustainability and outstanding comprehensive performance. Here, a composite strategy of in situ polymerizing a petroleum-based monomer with the presence of an industrialized bio-derived polymer in a quasi-solvent-free system is introduced, affording the plastic with excellent mechanical robustness, impressive thermal and solvent stability, as well as low energy, consumes during production, processing, and recycling. Particularly, the plastic can be easily processed into diverse shapes through 3D printing, injection molding, etc. during polymerization and further reprocessed into other complex structures via eco-friendly hydrosetting. In addition, the plastic is mechanically robust with Young's modulus of up to 3.7GPa and tensile breaking strength of up to 150.2MPa, superior to many commercially available plastics and other sustainable plastics. It is revealed that hierarchical hydrogen bonds in plastic predominate the well-balanced sustainability and performance. This work provides a new path for fabricating high-performance sustainable plastic toward practical applications, contributing to the circular economy.