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[Display omitted] • Antifouling property of the membrane was improved by UV-initiated grafting. • Surface charge was regulated by electrostatic adsorption. • The membrane showed excellent antifouling properties when filtrating various foulant solutions. • The membrane was very stable due to the covalent bonding. In this study, positively charged monomers were grafted onto negatively charged membranes via UV radiation to improve the antifouling/antibiofouling properties of the polymeric membrane and the stability of the modification layer. The surface properties, morphologies, antifouling and antibiofouling properties, and stability of the modified membranes were systematically characterized. Results indicated that the introduction of [2-(methacryloyloxy) ethyl] trimethylammonium chloride (MTAC) monomers onto polyethersulfone (PES)/sulfonated polyethersulfone (SPES) membranes effectively increased the surface hydrophilicity. Meanwhile, the surfaces were neutralized with ~0 mV zeta potential in pH 3–10. Moreover, the formation of a polyampholytic copolymer and the antibacterial ability of MTAC considerably improved the antibiofouling properties of the modified membranes. The MTAC-grafted PES/SPES membranes showed excellent antifouling/antibiofouling properties during the treatment of various types of wastewater, including bovine serum albumin solution, oil/water emulsion, and bacterial suspension. Therefore, this study provides a simple and effective method of constructing stable and antifouling membranes for sustainable water treatment. [ABSTRACT FROM AUTHOR]

The commercial application of lithium–sulfur batteries is mainly restricted by their quick capacity decay and poor cycle life due to the shuttle effect, insulating nature of sulfur, and cathode structure pulverization. Herein, a new type of lithiated polymer binder based on a vinyl chloride-acrylic copolymer (VCA) is constructed for the sulfur cathode. Experimental results and theoretical calculations both reveal that the lithiated vinyl chloride-acrylic copolymer (LVCA) binder possesses strong interactions with lithium polysulfides, enabling inhibition of the shuttle effect. The high adhesion strength of the LVCA binder effectively maintains electrode integrity and ensures good electronic conductivity during long-term cycling. Besides, the appropriate electrolyte uptake and abundant –COOLi groups of the LVCA binder endow the sulfur cathode with fast lithium-ion diffusion. Consequently, the sulfur cathode with the LVCA binder exhibits a 2.0-fold increase in the discharge capacity and a low capacity decay of only 0.04% per cycle after 800 cycles at 1C, compared to that with a PVDF binder. The rate performance of the sulfur cathode with the LVCA binder is also greatly enhanced, retaining a high discharge capacity of 704.9 mA h g−1 at 2C. This study provides an effective strategy for improving the electrochemistry performance of lithium–sulfur batteries by simple application of a new and low-cost copolymer binder. [ABSTRACT FROM AUTHOR]

Abstract A polyvinyl chloride (PVC)-based positively-charged nanofiltration membrane was fabricated from polyvinyl chloride- graft -poly(N,N -dimethylaminoethyl methacrylate) by heating and crosslinking treatment. We characterized the surface chemical compositions, membranes structures, surface hydrophilicity and surface charges of the prepared membrane. The estimated membrane pore diameter is 1.98 nm and the pore diameters are in the range of 0.5–2.0 nm. The membrane exhibits excellent water permeability (9.3 L m−2 h−1 bar−1) and salt rejection (93.1% with MgCl 2 solution). Both the heating treatment and crosslinking reaction can diminish the pore size of the precursor membrane. The membrane hydrophilicity is improved after quaternization, leading to higher water permeability compared with the membrane treated by heating only. Moreover, surface quaternization and crosslinking offer the membrane excellent pressure resistance and long-term stability. The prepared nanofiltration membrane has great promise in many applications including water softening and multivalent ion removal. Highlights • Positively charged nanofiltration membrane was directly fabricated from polyvinyl chloride copolymer. • The membrane was formed after the heating treatment and crosslinking reaction. • The membrane exhibited 9.3 L m−2 h−1 bar−1 of water permeability and 93.1% of MgCl 2 rejection. • The membrane had excellent pressure resistance and long-term stability. [ABSTRACT FROM AUTHOR]

Abstract Different from the typical interfacial polymerization for nanofiltration membrane fabrication, we proposed a novel method to prepare charged nanofiltration membrane via rapid immersion thermal annealing process with the ultrafiltration membrane, which was prepared from the amphiphilic copolymer, poly(vinyl chloride) -g- poly(2-(dimethylamino)ethyl methacrylate) (PVC -g- PDMA) via non-solvent induced phase separation. The pore structures and chemical properties of the membranes, and annealing conditions including the media where the membrane was annealed, annealing temperature and time, were investigated in detail. It is found that the porous separation layer was collapsed to be a stable, defect-free, and smooth film as the dense separation layer of nanofiltration membrane when it was annealed in n -heptane above its glass transition temperature (T g) for only 1 min while the pore size cutoff was tailored from 20 nm to 2 nm. Salt rejections were in the order of MgCl 2 > NaCl > MgSO 4 > Na 2 SO 4 at neutral condition due to Donnan repulsion, indicating a typical positively charged nanofiltration membrane. Overall, this rapid immersion thermal annealing process provides a facile and effective strategy to tailor ultrafiltration membrane toward nanofiltration applications for amphiphilic copolymer based membranes. Graphical abstract fx1 Highlights • NF membrane was formed rapidly via thermal annealing from ultrafiltration membrane. • Pore size of NF membrane could be tailored by the annealing condition. • The positively charged NF membranes showed high divalent cations rejection and water permeace. • Outstanding adhesive strength between the supports and the separation layer was attained. [ABSTRACT FROM AUTHOR]

ABSTRACT A braid-reinforced hollow fiber membrane with mechanically stable coating layer was prepared by coating a blended polymer dope solution on an alkaline-treated poly(ethylene terephthalate) (PET) braid. The alkaline treatment was carried out to endow the PET braid surface with more polar groups and better hydrophilicity. The results showed that the bonding strength between the hydrophilic coating layer and modified PET braid was about two times as great as that between the coating layer and original PET braid, while the pure water permeability (PWP) of the membrane remained unchanged when the PET braid was simply treated in 3 wt % potassium hydroxide (KOH) solution at 90 °C for 1 h or 1 wt % KOH solution for 6 h. The proposed modification approach proved to be a facile, low-cost, and effective method to improve bonding strength between the coating layer and the braid, while other properties, such as PWP and morphology of the coating layer, of the braid-reinforced hollow fiber membranes were not altered, indicating promising potential in membrane engineering. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46104 [ABSTRACT FROM AUTHOR]

ABSTRACT Fluorinated acrylate emulsions have been extensively applied for hydrophobic surface coatings. To obtain fluorinated emulsions of low surface energy, amphiphilic sulfonyl macro emulsifiers consisting of 2-(perfluorohexyl) ethyl acrylate (PFHEA) and 2-acrylanmido-2-methylpropanesulfonic acid (AMPS) were designed via radical polymerization and subsequently used for the emulsion copolymerization of PFHEA, methyl methacrylate (MMA), and methyl butyl acrylate (MBA). Under optimum synthesis conditions, the emulsifier displayed superior emulsification properties such as high monomer conversion, small particle size, and excellent stability compared with conventional emulsifiers. The corresponding emulsions with sulfonyl macro emulsifiers exhibited extreme low surface energy (9.8 mN/m) and outstanding hydrophobicity due to high contents of fluorinated chains, as well as thimbleful hydrophilic sulfonyl groups, which shows the great potential in water repellent modification application. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44921. [ABSTRACT FROM AUTHOR]

ABSTRACT To improve the antifouling property of poly(vinyl chloride) (PVC) membranes, a series of poly(methacrylic acid) grafted PVC copolymers (PVC -g-PMAA) with different grafting degree were synthesized via one-step atom transfer radical polymerization process utilizing the labile chlorines on PVC backbones followed by one-step hydrolysis reaction. PVC/PVC -g-PMAA blend membranes with different grafting degree and copolymer content were prepared by nonsolvent induced phase separation method. The surface chemical composition, surface charge, membrane structures, wettability, permeability, separation performances and the fouling resistance of blend membranes were carefully investigated. The results indicated that the PMAA chains were segregated towards the surface and the membranes were endowed with negative charge. The hydrophilicity and permeability of the blend membranes were obviously improved. Furthermore, the antifouling ability especially at neutral or alkaline environments was also significantly increased. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42745. [ABSTRACT FROM AUTHOR]

To functionalize poly(vinyl chloride) (PVC) for various applications, monomers containing tertiary amine group are incorporated into PVC via atom transfer radical polymerization (ATRP) initiated by the labile chlorines in their backbones. The kinetics of synthesis was carefully investigated, and it is proven that the grafting polymerization process can be effectively controlled by regulating the reaction time. The membranes are fabricated using PVC and copolymers by non-solvent induced phase separation (NIPS) process. The hydrophilicity and pore structure of copolymer membranes were enhanced as well, these membranes are endowed with positive charge. When PDMA% ( i.e., the PDMA weight percentage in copolymer) is 31.1%, the flux and Victoria blue B rejection are 26.0 L·m·h (0.5 MPa) and 91.2%, respectively. Thus, the newly synthesized polymer is proven to be a promising material for dye separation with positive charges. [ABSTRACT FROM AUTHOR]