Styrene Maleic Anhydride Research Articles

Fabrication of PVC-based electromagnetic interference shielding composite film by positively charged SMA enhancing the dispersibility of carbon nanomaterial

To address the weak binding force and poor dispersion stability of carbon (C) nanoparticles in current non-covalent modification methods, we employed organic amine-grafted styrene maleic anhydride copolymers (SMA-N) to modify C nanoparticles (C@SMA-N) through π–π conjugation and positive charge interactions. The obtained C@SMA-N has excellent dispersion in N, N-dimethylacetamide (DMAc), which is attributed to the enhanced steric hindrance and electrostatic repulsion from the grafted organic amine chains. To study the impact of surface modification on the electromagnetic interference shielding effectiveness (EMI SE), C@SMA-N was used as a conductive filler in polyvinyl chloride (PVC) composite films, which exhibits a higher EMI SE performance than pristine C nanoparticles. Particularly, the obtained C@SMA-N using polyether amine (PEA) (C@SMA-PEA) exhibits a better EMI SE performance. By optimizing the SMA-PEA grafting parameters, the PVC/C@SMA-PEA composite films transition from insulators to conductors at a C@SMA-PEA content of 0.3 wt%. To achieve a higher EMI SE performance, the filler content, mixed filler composition, and film thickness were optimized. The results indicate that with a total filler content of 20 wt% and a mixed filler comprising fibrous form carbon nanotubes (CNT) and particles form carbon black (CB) in a 10:1 mass ratio (CB@SMA-PEA to CNT@SMA-PEA), the composite film has a thickness of 0.08 mm and an EMI SE value of 20.2 dB. Increasing the thickness to 0.2 mm enhances the EMI SE value to 31.5 dB. These findings indicate that thinner films have a higher EMI SE performance and promising application prospects in the field of electromagnetic shielding.

A lanthanide luminescent sensor doped polymer dots for ratiometric fluorescence detection of hydrogen sulfide

As one of the indexes of food freshness, hydrogen sulfide content is closely related to food spoilage. A dual-emission sensor for H2S detection was reported in this paper. Poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] Polymer dots (MEH-PPV-Pdots) were prepared by copolymer of poly [2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] and styrene-maleic anhydride. The sensor was obtained by embedding purple MEH-PPV-Pdots in a green MOF. The accommodated MEH-PPV-Pdots were considered as the reference signal, while copper ions on the host skeleton served as accessible reaction sites, allowing MEH-PPV-Pdots/Tb0.99Cu0.01-MOF to selectively sense H2S. The sensor exhibited reduced green fluorescence and proportional response to H2S. Because H2S can transfer charge on copper ions and thus affect the green light emitted by rare earth ions. The results showed that the sensor had good stability to H2S in HEPES buffer, fast response, obvious color change, high selectivity and sensitivity. The sensor has been applied to the detection of aquatic products, showing good visualization effect.

Photo‐induced polymerization of styrene‐maleic acid copolymers for the extraction of membrane proteins

AbstractWe report herein the photoinduced electron/energy transfer–reversible addition‐fragmentation chain transfer (PET‐RAFT) polymerization of styrene‐maleic anhydride (SMAnh) using the photocatalyst, zinc tetraphenylporphirine, under a white cool LED light. PET‐RAFT is an easy and convenient polymerization method that does not require deoxygenation unlike other radical polymerizations. Various parameters, for example, the amount of styrene in the feed or the solvent, and their influence on the polymerization were studied. After hydrolysis of the anhydride moieties, the resulting styrene‐maleic acid (SMA) copolymers obtained by PET‐RAFT copolymerization were evaluated for their solubilization efficiency of three different membrane proteins, BmrA and AcrB, overexpressed in Escherichia coli, and A2AR, expressed in insect cells (Sf9). The different copolymers provided similar solubilization rates to the commercially available SMA; however, a highly improved migration behavior on sodium dodecyl‐sulfate polyacrylamide gel electrophoresis was observed which could, facilitate downstream analyses. Overall, we demonstrated that PET‐RAFT is a versatile oxygen tolerant polymerization technique to yield SMA, a suitable polymer for biochemical applications.

Dipole Orientation Engineering in Crosslinking Polymer Blends for High-Temperature Energy Storage Applications.

Polymer dielectrics that perform efficiently under harsh electrification conditions are critical elements of advanced electronic and power systems. However, developing polymer dielectrics capable of reliably withstanding harsh temperatures and electric fields remains a fundamental challenge, requiring a delicate balance in dielectric constant (K), breakdown strength (Eb), and thermal parameters. Here, amide crosslinking networks into cyano polymers is introduced, forming asymmetric dipole pairs with differing dipole moments. This strategy weakens the original electrostatic interactions between dipoles, thereby reducing the dipole orientation barriers of cyano groups, achieving dipole activation while suppressing polarization losses. The resulting styrene-acrylonitrile/crosslinking styrene-maleic anhydride (SAN/CSMA) blends exhibit a K of 4.35 and an Eb of 670 MV m-1 simultaneously at 120°C, and ultrahigh discharged energy densities (Ue) with 90% efficiency of 8.6 and 7.4 J cm-3 at 120 and 150°C are achieved, respectively, more than ten times that of the original dielectric at the same conditions. The SAN/CSMA blends show excellent cyclic stability in harsh conditions. Combining the results with SAN/CSMA and ABS (acrylonitrile-butadiene-styrene copolymer)/CSMA blends, it is demonstrated that this novel strategy can meet the demands of high-performing dielectric polymers at elevated temperatures.

Enhanced flame-retardant phase change materials with good shape stability for thermal management

Phase change materials (PCMs) have become pivotal components in many fields such as energy storage, thermal management, and photothermal conversion. However, challenges including leakage, flammability, and low thermal conductivity have impeded their broad application. In this work, a cross-linked solid-solid PCM (SPEG) using polyethylene glycol (PEG) and styrene-maleic anhydride copolymer (SMA) was synthesized. To enhance flame retardancy and thermal conductivity, black phosphorus (BP) and expandable graphite (EG) were introduced into the PCM matrix, yielding the target product (SPEG-BP/EG PCM) with enhanced properties. The analysis demonstrated that the SPEG-BP/EG sample with the ratio BP/EG of 1:1 (SPEG-BP/EG-1) exhibited a notable decrease in peak heat release rate and total heat release by 55.2 % and 13.2 %, respectively, compared to the SPEG sample. Moreover, thermal conductivity was improved from 0.18 W m−1 K−1 (SPEG) to 0.59 W m−1 K−1 for SPEG-BP/EG-1. The inclusion of SMA in crosslinking facilitated the transition of PEG's phase change behavior from solid-liquid to solid-solid, maintaining an enthalpy efficiency of 64.0 %. SPEG-BP/EG-1 exhibited excellent dimensional stability and cycling performance in open heating/cooling cycle tests, remaining chemically stable even after 60 heating/cooling cycles, as confirmed by DSC analysis. Furthermore, thermal management performance was evaluated using an LED light bulb, revealing a notable reduction of 9.4 °C in the maximal working temperature facilitated by SPEG-BP/EG PCM. This work presented a comprehensive strategy to mitigate the challenges of flammability, low thermal conductivity, and leakage associated with conventional PCM (PEG), thereby having great potential in practical applications in thermal management.

Miscible blends of chemically‐modified poly(phenylene oxides) with styrene copolymers containing polar groups

AbstractPoly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) is well‐known to be miscible with polystyrene, but immiscible with styrene copolymers containing polar groups. Certain nitrated‐PPOs (NPPOs) were found to be miscible with copolymers of styrene/acrylonitrile (SANs), copolymers of styrene/maleic anhydride (SMAs), a terpolymer of α‐methylstyrene/styrene/acrylonitrile (α‐MS/S/AN), and a copolymer of o‐ and p‐chlorostyrene (PCS). Also, certain simultaneously nitrated‐ and chlorinated‐PPOs (NCPPOs) were found to be miscible with SANs, SMAs and PCS whereas immiscible with the α‐MS/S/AN. The miscibility was indicated by the presence of a single composition‐dependent glass‐transition temperature for a given blend across the entire range of blend compositions tested. The miscibility of the aforementioned NPPOs and NCPPOs blends with SAN1 and SMA1 is attributed to hydrogen bonding of hydroxy groups of NPPOs and NCPPOs with nitrile groups and carbonyl groups, respectively, based on the literature information. The hydroxy groups were generated during nitration and simultaneous nitration/chlorination of PPO as a result of nucleophilic chain scission. Miscible blends of ‐NPPO/SAN and ‐NPPO/SMA with ABS1 showed a substantially better balance of the following properties than a comparable immiscible‐NPPO/SAN blend and a ‐PPO/SAN blend with ABS1: notched Izod impact strength, tensile properties, heat distortion temperature and gasoline stress‐crack resistance.Highlights Nitration and simultaneous nitration/chlorination of PPO generated hydroxyl end groups. Certain NPPOs and NCPPOs were miscible with SANs, SMAs and PCS. Miscibility indicated by a single composition dependent Tg for a given blend. Miscibility attributed to hydrogen bonding of respective functional groups. Impact‐modified miscible‐NPPO/SAN blends and ‐NPPO/SMA blends with ABS1 as impact modifier had good key properties.

Ionic Liquid‐Supported Single‐Sodium‐Ion‐Conducting Styrene‐Maleic Anhydride Copolymer for Energy Storage Devices

Wide‐ranging research has been done on ionic liquid (IL)‐incorporated conducting polymers in energy storage devices. Herein, by taking the reaction advantage of styrene maleic anhydride (SMA) copolymer with sodium hydroxide, a sodium ion having polymeric material as an electrolyte is synthesized. 1,8‐Diazabicyclo[5.4.0]undec‐7‐enium acetate (DBU acetate) is prepared as an IL and added to the prepared polymer electrolyte to increase the matrix flexibility, semisolid nature, and ionic mobility inside the matrix. This semisolid sodium ion‐based electrolyte shows conductivity in the order of 10−5 S cm−1 and an electrochemical stability window of 2.52 volts with >97% of ionic transference. It also shows the diffusivity constant in the order of 10−4 m2 s−1 and ionic mobility in the order of 10−3 m2 v−1 s−1 at 30 °C. The hydrogel matrix shows a correlated type of hopping with a power exponent <1 at 30 °C with low‐energy requirement of ionic transport, that is, 0.709 eV. A high amount of capacitance is associated with electrolyte that has an insignificant electrode contribution. On behalf of these findings, SMA‐IL‐based semisolid polymer electrolyte confirms its potential for application in sodium ion‐based energy storage systems.

Superelastic Polymer Aerogel with Superamphiphilicity.

Elastic aerogels have become a research hot spot in both academia and industry recently. The reported elastic aerogels are all made of hard materials by controlling their shapes. Herein we report an elastic aerogel made of a polymer elastomer with entropy elasticity. In the aerogel, cross-linked carboxyl nitrile rubber nanoparticles with hydrophilicity are dispersed in hydrophobic derivative of styrene-maleic anhydride alternating copolymer, forming a very special micro-nano surface structure with hydrophilic protrusions and hydrophobic depressions on the aerogel wall; therefore, the aerogel is not only superelastic but also superamphiphilic. A leak-free phase-change composite was prepared using the aerogel and paraffin, which can maintain at phase change temperature of paraffin for a longer time than the traditional one. The aerogel is also extremely suitable for desalination evaporators in solar-driven interfacial evaporation technology due to its superamphiphilicity, superelasticity, and ability to absorb sunlight. Exceptional evaporation rate of 2.78 kg·m-2·h-1 and evaporation efficiency of 170% could be reached even without using expensive light-absorbing materials. The evaporation rate exceeds that of most evaporators with expensive light-absorbing materials, and the evaporation efficiency exceeds the theoretical limit of conventional 2D solar evaporators. Both the phase-change composite and the evaporator can be easily recovered because the novel superelastic aerogel reported in this work is also recyclable.

Improving foamability and foam stability of poly(ethylene terephthalate) through chemical modification with styrene maleic anhydride

Improving foamability and foam stability of poly(ethylene terephthalate) through chemical modification with styrene maleic anhydride

Unlocking the potential of zwitterionic vapor-induced phase separation membranes synthesized from maleic anhydride in polyvinylidene fluoride-based systems for antifouling applications

This work presents an approach to form zwitterionic porous poly(vinylidene fluoride) (PVDF) membranes fabricated by vapor-induced phase separation (VIPS). The reaction between maleic anhydride groups, incorporated initially in the casting solution by blending styrene maleic anhydride (SMA), with 3-((3-aminopropyl)dimethylammonio)propane-1-sulfonate led to the desired zwitterionic moieties. XPS and FTIR analyses confirm the functionalization of the membrane. SEM analyses revealed that it did not have any major impact on the membrane morphology deemed to be close to bicontinuous. While the mean pore size of the virgin membrane was 0.57 μm, it increased to 0.85 μm suggesting the pore-forming effect of SMA during the phase-inversion process. Hydration was significantly enhanced, attributed to the zwitterionic groups on the one hand, but also to the formation of carboxylic acid and amide groups following the ring-opening reaction. It led to significant resistance to bacterial attachment as tested with 4 strains of bacteria including Escherichia coli, Stenotrophomonas maltophilia, Staphylococcus aureus and Streptococcus mutans (>99 % reduction for each). Applied in cyclic water/bacterial solution filtration tests, the modified membrane showed clear improvement in overall performances. Hence, for the virgin membrane, the initial water permeability, flux recovery ratio after the first cycle and flux recovery ratio after the second cycle were found to be 3000 L m−2 h−1.bar−1, 12 % and 53 %, respectively. For the optimized zwitterionic membrane, they were measured to be 7000 L m−2 h−1.bar−1, 26 % and 100 %, respectively. The efficacy of styrene maleic anhydride as a precursor for achieving stable and efficient zwitterionization of PVDF microfiltration membranes is evidenced, rendering it valuable for the filtration of microorganism-containing wastewater. Moreover, its potential application extends to the biomedical realm.

Recognition and detection of histamine in foods using aptamer modified fluorescence polymer dots sensors

Histamine has been known as a momentous cause of biogenic amine poisoning. Therefore, the content of histamine in foods is strictly required to be controlled within a certain range. Here, an aptamer fluorescent sensor was developed for detection of histamine. Poly [(9, 9-di-n-octylfluorenyl-2, 7-diyl)-alt-(benzo [2,1,3] thiadia-zol-4, 8-diyl)] (PF8BT) and the styrene maleic anhydride copolymer (PSMA) were used for the preparation of PF8BT-Polymer dots (PF8BT-Pdots). PF8BT-Pdots and the cyanine3-phosphoramidite (Cy3) were linked through aptamer to achieve the ratiometric detection for histamine. PF8BT-Pdots were partly quenched by Cy3 due to the fluorescence resonance energy transfer (FRET), when the histamine molecule was recognized by aptamer on the surface of PF8BT-Pdots. A linear range (3–21 μmol/L) was obtained for histamine detection with a low limit of detection (LOD = 0.38 μmol/L). PF8BT aptamer Pdots (PF8BT-A) were used to detect histamine in simply treated aquaculture water and tuna. The cell imaging of HeLa cells presented a good biosecurity and outstanding fluorescent imaging capability of PF8BT-A. The aptamer fluorescent sensors provided a new platform for rapid and accurate detection of histamine in aquatic products and had great potential for the application in food safety and quality control.

Fabrication of PVA-based electromagnetic interference shielding composite film by improving the dispersibility of carbon nanomaterial via m-LDH modification

A good dispersion of carbon (C) nanoparticles is a crucial factor to ensure good electrical conductivity and electromagnetic interference shielding effectiveness (EMI SE) performance of polymer-based composite films. In the present work, water-dispersed monolayer layered double hydroxides (m-LDH) was used to modify the C nanoparticles via an in-situ growth method and applied as the conductive fillers for polyvinyl alcohol (PVA) composite films. The prepared C@m-LDH hybrids displayed good water dispersibility due to the in-situ growth of m-LDH with high dispersibility and small particle size on the surface of C nanoparticles, as well as the synergistic effect of styrene-maleic anhydride copolymer attached to the m-LDH surface. The property testing experiments for the PVA composite films demonstrated that compared with pristine C nanoparticles, as-prepared C@m-LDH hybrids exhibited greatly enhanced the electrical conductivity and higher EMI SE performance. Moreover, PVA/C@m-LDH composite film exhibit remarkably low permeation thresholds, especially PVA/CB@m-LDH composite film, CB@m-LDH content is only 0.4 wt%. In order to further improve the electrical conductivity and EMI SE performance, hybrid fillers of CB@m-LDH/CNT@m-LDH were added in the composite films with different mass ratios. Among, the polymer composite films containing 30 wt% CB@m-LDH/CNT@m-LDH with a mass ratio of 12:1 achieves a high EMI SE value up to 29 dB at a thickness of 0.2 mm, indicating the potential use of these materials for electromagnetic shielding application in the X-band frequency region. The present study paves the way for designing high-performance polymer-based composite film by Cnanoparticles functionalization and altering processing conditions for efficient microwave shielding material.

Synthesis and characterization of styrene‐maleic acid block copolymers with acrylic and methacrylic acids for potential use in membrane protein extraction

AbstractStyrene‐maleic acid (SMA) block copolymers with acrylic acid (AA) and methacrylic acid (MAA) were synthesized via a 3‐step process comprising: (1) photopolymerization of styrene and maleic anhydride in solution to yield an alternating styrene‐maleic anhydride (SMAnh) copolymer, (2) copolymerization of SMAnh with AA and MAA to yield SMAnh‐b‐AA and SMAnh‐b‐MAA block copolymers, and (3) base‐catalyzed hydrolysis of the anhydride groups to yield water‐soluble SMA‐b‐AA and SMA‐b‐MAA block copolymers. Copolymer compositions and average molecular weights were determined by the synthesis methodology used in which reversible chain transfer was a key component. Copolymer characterization was carried out by a combination of techniques, namely: ATR‐FTIR, 1H‐NMR, dilute‐solution viscometry, GPC, DSC, and TGA. These novel SMA block copolymers have been designed with a view to their use in membrane protein (MP) extraction from plant extracts and other naturally occurring substances of potential therapeutic value. The main function of the AA or MAA blocks is to widen the operational pH range of SMA in terms of (a) maintaining its water solubility at low pH and (b) stabilizing its MP assemblies in solution.

One-Step Synthesis of Polyethyleneimine-Grafted Styrene-Maleic Anhydride Copolymer Adsorbents for Effective Adsorption of Anionic Dyes.

Wastewater containing organic dyes has become one of the important challenges in water treatment due to its high salt content and resistance to natural degradation. In this work, a novelty adsorbent, PEI-SMA, was prepared by grafting polyethyleneimine (PEI) onto styrene-maleic anhydride copolymer (SMA) through an amidation reaction. The various factors, such as pH, adsorbent dosage, contact time, dye concentration, and temperature, which may affect the adsorption of PEI-SMA for Reactive Black 5 (RB5), were systematically investigated by static adsorption experiments. The adsorption process of PEI-SMA for RB5 was more consistent with the Langmuir isotherm model and the pseudo-second-order model, suggesting a single-layer chemisorption. PEI-SMA exhibits excellent adsorption performance for RB5 dye, with a maximum adsorption capacity of 1749.19 mg g-1 at pH = 2. Additionally, PEI-SMA exhibited highly efficient RB5 competitive adsorption against coexisting Cl- and SO42- ions and cationic dyes. The adsorption mechanism was explored, and it can be explained as the synergistic effect of electrostatic interaction, hydrogen bonding and π-π interaction. This study demonstrates that PEI-SMA could act as a high performance and promising candidate for the effective adsorption of anionic dyes from aqueous solutions.

Stable-dispersed organic/inorganic hybrids for enhanced comprehensive performances of vinyl ester resin

The heavy anticorrosive coating industry demands coatings with exceptional mechanical properties and corrosion resistance to withstand the challenges of severe corrosion environments. Incorporating graphene with barrier function into vinyl ester resins (VER) to achieve above-mentioned performances enhancements has garnered considerable attention. Herein, a novel solvent-free, nearly 100 % raw materials utilization polyfunctional acrylate (SMAGO-VER) has been developed by using styrene-maleic anhydride copolymer and GO covalent cross-linked hybrid (SMAGO) and acrylic coring-opening epoxy resin. SMAGO exhibited well stability and dispersibility in the resin system. The composite coating containing SMAGO-VER showed enhanced mechanical properties, thermal stability and corrosion resistance due to the synergistic effect of copolymer and GO. The mechanism of enhancement was elucidated through various evaluation methods such as electrochemistry and equivalent circuit model. To conclude, this approach provides an effective strategy to address the limitations of traditional VER materials for better application in the field of heavy anticorrosive coatings.

Synthesis and characterization of microencapsulated paraffin with melamine-urea-formaldehyde shell modified with lignin

The study aims to fabricate MUF/paraffin microcapsules with lignin nanoparticles (LNPs)/ melamine-urea-formaldehyde (MUF) resin as hybrid shell material with different LNPs addition were synthesized in oil-in-water emulsion stabilized synergistically by styrene/maleic anhydride (SMA) and LNPs. The morphological characterization of LNPs was observed by transmission electron microscopy (TEM). The particle size of LNPs, the mean particle size and ξ potentials of SMA/LNPs mixture at pH =4.5 were investigated by zeta potential measurement. Field emission scanning electron microscopy (FE-SEM), Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analyzer (TGA), and differential scanning calorimetry (DSC) were characterized the morphologies, crystallography, chemical component, thermal stability and phase change properties of MUF/paraffin microcapsules with different LNPs addition. The results showed that MUF/paraffin microcapsules were spherical. The LNPs did not influence the chemical structure or crystal type of MUF/paraffin microcapsules. When the LNPs addition was 0.15 g, the melting enthalpy and crystallization enthalpy is respectively 130.03 and 121.92 J/g and the encapsulation efficiency of MicroC-15 is 61.04 %.

Copolymers-functionalized metal-organic framework composite for efficient adsorption of rare-earth elements

Based on the Hard-Soft-Acid-Base theory, we developed and synthesized a unique crystalline adsorbent called MIL-101(Cr)-SMA-ED-PMG (SMA: styrene maleic anhydride; ED: ethylenediamine; PMG: N,N-di(phosphonomethyl)glycine). This adsorbent consists of polymer chains that are abundant in carboxyl and phosphate Lewis hard base groups. This was performed to enhance the efficient recuperation of electrophilic Lewis hard acid rare earth elements. The Neodymium(III) (Nd3+) and Europium(III) (Eu3+) ions reached adsorption equilibrium in the MIL-101(Cr)-SMA-ED-PMG material after 6 h at pH 5. The adsorption of Nd3+ and Eu3+ follows the pseudo-second-order kinetic and Langmuir models. The maximum adsorption capabilities were 102.7 mg/g for Nd3+ and 110.4 mg/g for Eu3+. In addition, when applying a concentration of 0.3 mol/L of HNO3 or HCl, the adsorbent was nearly completely desorbed, and it remained stable for five cycles. The order of adsorption for the different REE ions was as follows: Eu3+ > Nd3+ > Ce3+ > La3+. The MIL-101(Cr)-SMA-ED-PMG compound demonstrated a remarkable 84 % selectivity in adsorbing Eu3+ compared to the other metal ions in the mixture (Na+, Mg2+, Co2+, Ni2+, and Zn2+). Furthermore, the adsorption of Eu3+ was not significantly influenced by changes in the aqueous conditions. The experiment conducted on a zinc ore simulated leachate exhibited the material remarkable capacity for Eu3+ separation and enrichment. MIL-101(Cr)-SMA-ED-PMG exhibits strong adsorption properties, exceptional selectivity, effective desorption, and significant potential for the recovery of rare earth elements (REEs).

Improved Electrical Properties of Organic Modified Thermoplastic Insulation Material for Direct Current Cable Application.

To achieve exceptional recyclable DC cable insulation material using thermoplastic polypropylene (PP), we have introduced the organic polar molecule styrene-maleic anhydride copolymer (SMA) into PP-based insulation materials following the principles of deep trap modification. PP, PP/SMA, PP/ethylene-octene copolymer (POE), and PP/POE/SMA insulating samples were prepared, and their meso-morphology, crystalline morphology, and molecular structure were comprehensively characterized. The results indicate that SMA can be uniformly dispersed in PP with minimal impact on the crystalline morphology of PP. The DC electrical properties of the materials were tested at temperatures of 30, 50, and 70 °C. The findings demonstrate that the introduction of SMA can improve the DC properties of the material in both PP and PP/POE. The thermal stimulated depolarization current results reveal that SMA can introduce deep traps into the material, thereby improving its DC properties, which is in agreement with the quantum chemical calculation results. Subsequently, a bipolar carrier transport model was employed for coaxial cables to simulate the space charge distribution in the insulation layer of the four sets of insulation samples as well as the actual cable in service. The results highlight that SMA can significantly suppress space charge in PP and PP/POE systems, and it exhibits excellent electric field distortion resistance. In summary, the results illustrate that SMA is expected to be used as an organic deep trap modifier in PP-based cable insulation materials.

Open tubular capillary electrochromatography with dual-responsive polymer as coating for separation of chromones

Fabricating polymeric coatings that are responsive to multiple/dual stimuli is crucial and remains a major challenge in the development of highly efficient open tubular capillary electrochromatography (OT-CEC). In this study, a pH and temperature-responsive block copolymer, poly(styrene-maleic anhydride 2-dimethylamino ethyl methacrylate), P(St-MAn-DMAEMA), was designed and synthesized. Using P(St-MAn-DMAEMA) as the coating, an OT-CEC protocol was constructed for the analysis of chromones. The morphology and hydrophobicity-hydrophilicity of the polymeric coating could change via varying the environmental conditions, affecting the separation efficiency of OT-CEC. Interestingly, the best performance of OT-CEC was achieved at pH 9.7 and 45 °C via tuning the interactions between the coating and the analytes. Additionally, the proposed OT-CEC method exhibited a good linear range for the detection of the three test chromones from 10.0 to 100.0 μM, with all correlation coefficients (R2) >0.997. The coatings also had good stability and reusability. This work provides an approach for the preparation of new multiple-stimuli-responsive polymeric coatings for the establishment of OT-CEC systems.

Fabrication of an electrically conductive separation layer with stable nanonetworks for efficient removal of heavy metals under an external voltage

Positively charged nanofiltration membrane shows great potentials in removing heavy metal ions from wastewater, but excellent separation and antifouling properties remain a challenge. Herein, a novel nanocomposite membrane with a dual-charged electrically conductive separation layer was fabricated by combining phase inversion, vacuum filtration and chemical crosslinking. The microstructure of PSF/sodium styrene-maleic anhydride copolymer (SMANa) composite membranes was systematically manipulated by adjusting the intermolecular binding state of SMA. Subsequently, various deposition layers were generated on the membrane surface by tuning the CNT/rGO ratios, and polyethylenimine (PEI) was also introduced by crosslinking with tannic acid (TA). The optimized membrane possessed a dual-charged separation layer with excellent conductivity and stable three-dimensional (3D) nanonetworks, and acted as cathode to achieve outstanding rejections of Cu2+(92.9%), Ni2+ (99.0%), Pb2+ (99.9%) and Cd2+ (99.5%) at a -3V voltage, with the permeate fluxes of 14.4～18.6 L/m2 h bar. This is ascribed to the synergistic effect among the electroreduction of metal ions, the chemical reaction with OH− to form hydroxides, the chelation with –OH and –NH2 groups, and the adsorption-induced electrostatic repulsion. Importantly, it also displayed superior stability over multiple runs and outstanding antifouling performances owing to the superposition of electrochemistry effect and stable hydration layers.