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ABSTRACT: This paper provides a comprehensive analysis of microwave‐induced low‐vacuum argon plasma treatment effects on the hydrophilic stability of various polymeric nanofiber webs. After plasma modification, samples are kept dry at room temperature in a dark place for the experiments, and the wettability of the nanofibers is improved by plasma treatment. The stability of the plasma‐treated hydrophilic nanofiber webs is observed for 55 days using water contact angle measurements. Different polymeric nanofiber webs show different stability. Based on the contact angle measurements, the surface starts to lose hydrophilicity during the first week after plasma treatment. The structural changes are examined by pore size measurements, scanning electron microscopy, and Fourier transform infrared spectroscopy. Two of the selected nanofiber webs are used as microfilters for separation of oily wastewater with a cross‐flow separation unit to measure the effect of the plasma treatment under wastewater. The permeability and selectivity of the plasma‐treated and untreated samples are compared. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46751. [ABSTRACT FROM AUTHOR]

ABSTRACT Hydrolyzed proteins previously shown to aggregate in aqueous solution were compounded into synthetic polyisoprene rubber (IR). Modulus increases of up to 232% resulted from protein reinforcement of IR. Increased hydrogen bonding on amine groups and the presence of β-sheets in the protein phase were observed via Fourier transform infrared (FTIR) spectroscopy. The total β-sheet amount relative to the IR content strongly correlated to the modulus and varied with the protein concentration, protein aggregation state, and compounding conditions. Isotropic protein aggregates on the order of hundreds of nanometers were observed by scanning electron microscopy with energy dispersive x-ray spectroscopy (SEM-EDX). The aggregates were evenly dispersed throughout the rubber matrix after compounding. The composite glass transition temperature ( Tg) was unchanged from the control, which indicated that the protein and rubber existed as two discrete phases. Remarkably, protein β-sheet structures were observed in FTIR even after rubber compounding under harsh conditions. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46026. [ABSTRACT FROM AUTHOR]

ABSTRACT Membrane bioreactor (MBR) as a hybrid technology for wastewater treatment is becoming more popular for wastewater treatment. However, membrane fouling has hindered the widespread application of MBRs. Many efforts have been done for fouling mitigation. In this study, high flux and antifouling microfiltration membranes with unique surface structure, high surface porosity, and permeability were prepared by electrospinning technique. Initially, the optimum thickness of electrospun polyacrylonitrile (PAN) membranes was determined and then, electrospun PAN membrane at optimum thickness were prepared by embedding para-aminobenzoate alumoxane (PABA) nanoparticles at different concentrations. The effect of PABA nanoparticles on membrane performance was investigated. To investigate the characterization of the prepared membranes Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, and water contact angle measurement were employed. The flux recovery ratio results revealed that the antifouling properties of the electrospun PAN membrane were enhanced by modification. The 3 wt % electrospun PABA embedded PAN had the best permeability, hydrophilicity, and antifouling properties among the fabricated membranes and showed remarkable reusability during filtration. The results obtained suggested that the high flux and antifouling electrospun PAN membranes embedded PABA nanoparticles could be used as MBR membranes. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45738. [ABSTRACT FROM AUTHOR]

ABSTRACT Our previous study on castor oil (CO) and poly(ethylene glycol) (PEG)-based shape memory polyurethane (PU) films indicated that cell spreading on the polymer surface, cell morphology, and adhesion of fibroblast are closely related to the composition of the polymer that influences surface properties. This integrated experimental and computational study is designed to investigate the effect of important parameters such as surface roughness, crystallinity, hydrophilicity, distribution of hard/soft segments, and topology of the surface on protein adsorption for CO- and PEG-based PUs. Analyses indicate that the crystallinity percentage highly promotes bovine serum albumin (BSA) adsorption. Roughness together with topological features determines BSA adsorption rate and concentration. Hydrophilicity and hard segment content seem to have less critical effect on adsorption. Distribution of hard segments into the soft segments emerges as another important factor for protein adsorption. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45669. [ABSTRACT FROM AUTHOR]

ABA-type amphiphilic triblock copolymers (TBCs) were synthesized by a reversible addition fragmentation chain transfer (RAFT) process with a telechelic polystyrene macro-RAFT agent and 4-[n-(acryloyloxy)alkyloxy]benzoic acid monomers. Ultrafiltration (UF) membranes were fabricated by a phase-inversion process with blends of the TBC, poly(vinylidene fluoride) (PVDF), and poly(vinyl pyrrolidone) (PVP) in dimethylformamide. The UF-fabricated membranes were characterized by scanning electron microscopy, atomic force microscopy, water contact angle measurement, thermogravimetric analysis, and differential scanning calorimetry. Pure water permeation, molecular weight cutoff values obtained by the permeation of different molecular weight polymers as probe solutes, bovine serum albumin (BSA) solution permeate flux, and oil--water emulsion filtration tests were used to evaluate the separation characteristics of the fabricated membranes. The tripolymer blend membranes exhibited a higher flux recovery ratio (FRR) after the membrane was washed with sodium lauryl sulfate (0.05 wt %) solution for a BSA solution (FRR588%) and oil--water emulsion (FRR595%) feeds when than the PVDF--PVP blend membrane (57 and 80% FRR values for the BSA solution and oil--water emulsion, respectively). The pendant carboxylic acid functional moieties in this ABA-type TBC have potential advantages in the fabrication of high-performance membranes. [ABSTRACT FROM AUTHOR]

ABSTRACT In this study, the effect of dimethyl 5-sodium sulfoisophthalate (SSI) nanoparticles (NPs) on the antifouling properties of poly(ethylene terephthalate) (PET) electrospun nanofiber membranes (ENMs) was investigated through the ultrafiltration of C. I. Basic Blue 3. 3 dye. To reveal the tortuous effect of this additive on the antifouling properties, scanning electron microscopy was used for the characterization of the ENM structure and the optimization of the SSI NP content. Then, some selected physical and structural properties of the membrane, such as the porosity, moisture regain, contact angle, hydraulic permeability ( L p), and mechanical properties, in the optimized range of SSI NP contents were investigated. Finally, the influence of this additive on the rejection and flux recovery ratio of the prepared membranes was considered. Consequently, the antifouling properties were assessed with consideration of all of the aforementioned parameters. The SSI/PET2 membrane (that with 0.02% w/w SSI NPs with respect to the total amount of PET polymer and SSI NPs), with an average nanofiber diameter of 450 nm, a porosity of 78.44%, a moisture regain of 9.34%, a contact angle of 86.48°, an L p of 42,167 L h−1 m−2 bar−1, a tensile strength of 4.66 ± 0.04 MPa, a flux recovery ratio of 15.3%, and a final rejection of 95%, showed a significant enhancement in the antifouling properties compared with pristine PET ENMs. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44522. [ABSTRACT FROM AUTHOR]

ABSTRACT Surface modification is an effective approach to enhance the properties of polymeric membranes. In this work, the UV-photo-induced graft polymerization of acrylic acid (AA) onto the surfaces of polyamide thin film composite (TFC-PA) membranes was carried out using an immersion method performed under ambient conditions. The experimental results indicate that the membrane surface becomes more hydrophilic because of the appearance of new carboxylic groups on the surface after the modification. This reduces the water contact angle and increases the water permeability compared with the unmodified membrane. The membrane surface is relatively compact and smooth due to the formation of the polymeric AA-grafted layer. The separation performance of the modified membrane is improved with enhancements of the permeate flux and the retention of humic acid from aqueous feed solutions compared with those of the unmodified membrane. The fouling resistance of the membrane is also improved because of the higher maintained flux ratios and the lower irreversible fouling factors for the removal of various organic compounds from feed solutions. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44418. [ABSTRACT FROM AUTHOR]

ABSTRACT A zwitterionic poly(vinyl alcohol- co-ethylene) (PVA- co-PE) nanofiber membrane for resistance to bacteria and protein adsorption was fabricated by the atom transfer radical polymerization of sulfobetaine methacrylate (SBMA). The PVA- co-PE nanofiber membrane was first surface-activated by α-bromoisobutyryl bromide, and then, zwitterionic SBMA was initiated to polymerize onto the surface of nanofiber membrane. The chemical structures of the functionalized PVA- co-PE nanofiber membranes were confirmed by attenuated total reflectance-Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The morphologies of the PVA- co-PE nanofiber membranes were characterized by scanning electron microscopy. The results show that the poly(sulfobetaine methacrylate) (PSBMA) was successfully grafted onto the PVA- co-PE nanofiber membrane, and the surface of the nanofiber membrane was more hydrophilic than that of the pristine membrane. Furthermore, the antibacterial adsorption properties and resistance to protein adsorption of the surface were investigated. This indicated that the PSBMA-functionalized surface possessed good antibacterial adsorption activity and resistance to nonspecific protein adsorption. Therefore, this study afforded a convenient and promising method for preparing a new kind of soft and nonwoven dressing material with antibacterial adsorption and antifouling properties that has potential use in the medical field. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44169. [ABSTRACT FROM AUTHOR]

ABSTRACT In this study a platform is laid out for the creation of a multitiered surface exhibiting switchable wettability. This is done through a combination of both an acrylate-based polymer understructure photopolymerized into a pillared array, and selectively placed surface treatments on these pillars. The acrylate-based polymer is created through a systematic study and is shown to exhibit drastic alterations in material stiffness over a 19 °C temperature transition under aqueous conditions, allowing for stiff, erect pillars in the low temperature state, and pliable pillars that can easily be bent in the high temperature state. The glass transition temperature and onset temperature for the polymer system is found to be 49 and 30 °C, respectively. Three different surface treatments, including trichloro(1H,1H,2H,2H-perfluorooctyl)silane, polydimethylsiloxane, and polydopamine, are investigated using static contact angle studies, and are selectively deposited onto the pillared surface such that a hydrophobic surface is exposed with the pillars erect, and a hydrophilic surface is exposed with the pillars in the bent state. The surface is shown to transition between first a hydrophobic, then hydrophilic state and return to a hydrophobic state when the investigations are coupled together forming a hierarchical surface structure. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44122. [ABSTRACT FROM AUTHOR]

ABSTRACT Zn-Al layered double hydroxide (LDH)-entrapped poly(ether sulfone) (PES) ultrafiltration membranes with four different weight percentages, 0.5, 1.0, 2.0, and 3.0%, were prepared by a phase-inversion method. Characterization by scanning electron microscopy, atomic force microscopy and contact angle (CA), equilibrium water content, porosity, average pore size, mechanical strength, and ζ potential measurement were used to evaluate the morphological structure and physical and chemical properties of membranes. Static protein adsorption, filtration, and rejection experiments were conducted to study the antifouling properties, water permeability, and removal ability of the modified membranes. The results show that significant change occurred in the membrane morphology and that better hydrophilicity, water permeability, and antifouling ability were also achieved for the PES/LDH membranes when a proper amount of LDH was used. For example, the CA value decreased from 66.60 to 50.21°, and the pure water flux increased from 80.21 to 119.10 L m−2 h−1 bar−1 when the LDH loading was increased from 0 to 2.0 wt %. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43988. [ABSTRACT FROM AUTHOR]

ABSTRACT High flux PP/EVOH nanofibrous composite microfiltration membrane (P/E-NCMM) based on polypropylene (PP) (575 nm) and polyethylene- co-polyvinyl alcohol (EVOH) nanofibers (248 nm) with low operation pressure for liquid filtration was fabricated by melt blending extrusion. PP nanofibers as the scaffold played a supporting role, and EVOH nanofibers filled in the PP nanofibers network structure narrowed the pore size and improved the wettability. Taking advantages of PP and EVOH nanofibers, the nanofibrous composite membrane created fascinating features for liquid filtration. The experimental results showed that the P/E-NCMM had high average pure water flux at low operating pressure. The P/E-NCMM with 30 wt % PP nanofibers showed high water flux [450.9 L/(m2 h)] even at very low feeding pressure (0.05 MPa) with above 95% retention for TiO2 suspension. The results indicated that the P/E-NCMM prepared by this method had great potential for the application in liquid filtration. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43585. [ABSTRACT FROM AUTHOR]

ABSTRACT A new kind of membrane formation polymer, cardo poly(arylene ether ketone) bearing hydrophilic hydroxyl groups (PEK-OH) was synthesized from the biphenol monomer 2-(2-hydroxyethyl)-3, 3-bis (4-hydroxyphenyl)-isoindolin-1-one (PPH-OH), and 4, 4′-difluorodiphenylketone. PEK-OH asymmetric ultrafiltration membranes were prepared using the immersion coagulation phase inversion method. The PEK-OH membrane prepared using the optimized conditions exhibited a pure water flux of 516 ± 18 L·m−2·h−1 and a 99.1 ± 1.4% rejection of bovine serum albumin (BSA) at an operating pressure of 0.1 MPa. The contact angle of PEK-OH membrane was 66.0 ± 2.4 lower than these of the PEK-C membrane (87.0 ± 2.8°, prepared from polymer PEK-C under the same membrane formation condition as PEK-OH membrane) and the UE50 membrane (84.0 ± 1.6°, a commercial PES ultrafiltration membrane). The amount of BSA protein adsorbed to the PEK-OH membrane under static condition was measured to be 3.12 μg·cm−2, which was greatly lower than that of 88.71 μg·cm−2 and 74.40 μg·cm−2 for the PEK-C and the UE50 ultrafiltration membranes, respectively. Under dynamic filtration of BSA experiments, the PEK-OH ultrafiltration membrane showed a 78.3% water flux recovery ratio, while only a 39.7% for the PEK-C membrane and 46.5% for UE50 membrane were detected in the first cycle. After three cycles of BSA and LYZ filtration, the flux recovery ratio of PEK-OH ultrafiltration membrane changed to be stable at 75% and 73%, while that of PEK-C and UE50 ultrafiltration membranes remained declining gradually. Thus, hydrophilic PEK-OH improves antifouling membrane property. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 132, 42809. [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]

ABSTRACT An environmental friendly regenerated cellulose membrane (RCM) was successfully prepared via NaOH/urea aqueous solution system by utilizing recycled newspaper (RNP) as the cellulose source. The morphological and chemical structure of resulting membrane were characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) spectroscopy, and thermogravimetric analysis (TGA). Results from FTIR and XRD verified that the transparent RCM possesses cellulose II structure. SEM observation revealed that the transparent RCM consist of homogeneous dense symmetric membrane structure and composed of a skin layer with mean roughness parameter Ra, obtained from AFM analysis of 29.53 nm. Pure water flux, water content, water contact angle, porosity, and pore size of the resulting membrane were also measured. This study promotes the potential of the cellulose-based membrane obtained from low cost cellulose source for application in filtration and separation system. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42684. [ABSTRACT FROM AUTHOR]

ABSTRACT In this study, a macroporous polypropylene membrane (MPPM) was grafted with hydrophilic poly( N-vinyl-2-pyrrolidone) (PNVP) based on a one-pot reversible-addition fragmentation chain transfer (RAFT) polymerization and click chemistry. First, we prepared the clickable membrane by bromination and following SN2 nucleophilic substitution reaction; then, click chemistry and RAFT polymerization were performed in one-pot to graft PNVP to the MPPM surface. The surface characterizations, including attenuated total reflectance/Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and field-emission scanning electron microscopy, illustrated that PNVP was really grafted onto the MPPM surface. The permeation and antifouling characteristics of the MPPMs were measured by the filtration of a bovine serum albumin dispersion; this showed that in contrast to the nascent membrane, the grafted membrane efficiently obstructed protein molecules because of the compactly grafted polymer chains. The hydrophilicity and antifouling properties of MPPM were greatly ameliorated after modification. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42649. [ABSTRACT FROM AUTHOR]

ABSTRACT In this study, ZnO/polyethylene membranes were fabricated via thermally induced phase separation method. A set of tests including FE-SEM, EDX, XRD, DSC, TGA, DMA, mechanical test, and pure water flux (PWF) for characterization of membranes were carried out. The results of EDX, XRD, and TGA analyses confirmed the presence of ZnO nanoparticles in the polymer matrix. The results of DSC analysis revealed that the melting point as well as the crystallinity of the membranes increased slightly with increasing ZnO content. However, glass transition temperature of the membranes was not affected by presence of the particles. Addition of nanoparticles also increased storage modulus, loss modulus. and tensile at break of the membranes due to the stiffness improvement effect of inorganic ZnO. Finally, it was observed that incorporation of the nanoparticles improved PWF of the membranes, whereas humic acid rejection decreased due to the increase in mean pore radius of membranes. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42338. [ABSTRACT FROM AUTHOR]

ABSTRACT Membrane-based separation processes are very susceptible to flux decline because of concentration polarization and fouling problems. Despite the immense applications of low-pressure driven microfiltration (MF) and ultrafiltration (UF) membranes in various fields, fouling is considered a major negative aspect, and it renders the membrane with a reduced lifetime. The important membrane properties, hydrophilicity, charge, and morphology mainly gained by the membrane during its formation process are considered to be deciding factors in fouling. In this review, we spotlight the effects of the hydrophilicity, charge, and morphology on MF and UF fouling, the principles of the most frequently used instrumentation techniques in predicting these factors, and measures that can be taken for fouling control. The review also focuses on the UF and MF membrane modification techniques used to attain high antifouling characteristics. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42042. [ABSTRACT FROM AUTHOR]

ABSTRACT The large scale production of bacterial surfactin-an anionic lipopeptide is restricted by its high cost of production. Surface sorption of surfactin causes membrane fouling, decreasing air permeation, or filtration efficiency of membranes used in bioreactors. The aim of this study was to elucidate surface properties leading to reduction or even the prevention of surfactin sorption on fibrous membranes. Surface modification of fibrous polyethylene terephthalate (PET) nonwoven membranes using cationic and/or anionic biopolymers, or an antiadhesive fluorinated polymer, with or without a prior air plasma treatment, resulted in membranes with varying surface properties. Membranes with superhydrophilic to superhydrophobic behavior with varying surface charges (positive, nul, and negative) were produced. Water contact angle (WCA), capillary uptake, as well as Zeta potential of each modified membrane, were quantified. Sorption tests using surfactin, were carried during 5, 24, and 48 h, at pH 7. The amphiphilic anionic lipopeptide sorbed on positively charged membranes as well as on negatively charged hydrophobic, hydrophilic, or superhydrophobic membranes. PET membrane functionalized with alternate deposition of chitosan and alginate presented surface properties (zeta potential of −20 mV and WCA = 80°), which was effective in rejecting 100% of the anionic surfactin both at an initial stage and at a late stage (after 48 h). Discussion is proposed to explain possible interactions between the anionic lipopeptide and the functionalized nonwovens. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41622. [ABSTRACT FROM AUTHOR]

ABSTRACT Protein-fouling of membranes has negative effects on the wide applications of membrane materials, such as poly(vinylidene fluoride) (PVDF), poly(ether sulfone) (PES)/polysulfone (PSf). Zwitterionic materials have recently been used and identified from high throughput screens of large libraries of monomers to modify membranes due to their stable anti-protein-fouling properties. 'Grafting from' polymerization is a technique involving monomers that are polymerized using an initiation reaction on the membrane surface. It is regarded as a simple, useful, and versatile modification approach to increase the anti-fouling properties of a membrane. This strategy provides controllable introduction of graft chains with a high density and a long-term chemical stability due to covalent attachment of graft chains. Graft density, chemistry, chain length, and conformation are all important parameters that need to be considered. This article presents a mini-review of recent progress on the 'grafting from' polymerization of zwitterionic monomers on the surfaces of PVDF and PES/PSf membranes, including an introduction of zwitterions and methods of graft polymerization. Various approaches such as free radical graft polymerization, photo-induced graft polymerization, and plasma-induced graft polymerization were compared based on uniformity and amount of grafted zwitterionic polymer, relative flux of modified membranes, simplicity and environment pollution of operation, and cost of technique. The application of different approaches and the performance of poly(zwitterion)-grafted PVDF and PES/PSf membranes are summarized according to recent research. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41781. [ABSTRACT FROM AUTHOR]

ABSTRACT Hydrophilic surfaces are known to be less prone to fouling. Ultrafiltration membranes are frequently prepared from rather hydrophobic polymers like polysulfone (PSU). Strategies to keep the good pore forming characteristics of PSU, but with improved hydrophilicity are proposed here. PSU functionalized with 1,2,3-triazole ring substituents containing OH groups was successfully synthesized through click chemistry reaction. The structures of the polymers were confirmed using NMR spectroscopy and Fourier transform infrared spectroscopy (FTIR). High thermal stability (>280 °C) was observed by thermal gravimetric analysis. Elemental analysis showed the presence of nitrogen containing triazole group with different degrees of functionalization (23%, 49%, 56%, and 94%). The glass transition temperature shifted with the introduction of triazole pendant groups from 190 °C (unmodified) to 171 °C. Ultrafiltration membranes were prepared via phase inversion by immersion in different coagulation baths (NMP/water mixtures with volume ratios from 0/100 to 40/60). The morphologies of these membranes were studied by field emission scanning electron microscopy (FESEM). The optimized PSU bearing triazole functions membranes exhibited water permeability up to 187 L m−2 h−1 bar−1, which is 23 times higher than those prepared under the same conditions but with unmodified polysulfone (PSU; 8 L m−2 h−1 bar−1). Results of bovine serum albumin protein rejection test indicated that susceptibility to fouling decreased with the modification, due to the increased hydrophilicity, while keeping high protein rejection ratio (>99%). © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41549. [ABSTRACT FROM AUTHOR]

ABSTRACT A polyvinylidene fluoride (PVDF) ultrafiltration (UF) membrane was modified by dispersing titanium oxide (TiO2) particles in a PVDF solution. PVDF flat-sheet membranes were prepared by a phase inversion method. This study investigates the potential low-fouling properties of these composite membranes during filtration, in darkness or under UV irradiation, of pure water and foulants representative of those found in membrane bioreactor processes: commercial bovine serum albumin (BSA) as a model protein and real soluble extracellular polymeric substances (EPS). The experimental results indicate that nanocomposite membrane has a structure with longer and larger macrovoid than neat PVDF membranes resulting in higher water flux performances. These higher flux performances were also due to an increase in surface hydrophilicity because of the presence of TiO2 particles. Moreover, such membranes are less prone to adsorption by BSA and present self-cleaning ability under static irradiation. During filtration of BSA and EPS without UV irradiation, nanocomposite membranes presented a little flux decline and reached stabilization more rapidly in comparison with PVDF membranes. Moreover, simultaneous UV irradiation during ultrafiltration has a benefit effect only on nanocomposite membranes for which initial flux was increased. Hydrophilic properties of nanocomposite membranes lead to better retention performances of BSA and EPS, which are still improved under UV irradiation. Finally, nanocomposite membranes under UV irradiation presented the best flux recovery ratio confirming their antifouling property. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41731. [ABSTRACT FROM AUTHOR]

ABSTRACT Nanoporous membranes based on self-assembled block polymer precursors are an emerging class of promising separation, purification, and sensing devices due to the ability of researchers to control the nanostructure and chemistry of these multifunctional materials and devices. In fact, modern polymer chemistry provides techniques for the facile, controlled synthesis of the block polymers that constitute these devices. These designer macromolecules, in turn, can then self-assemble into functional nanostructures depending upon the chemical identity of the synthesized block polymers and the thin film fabrication methods employed. After fabrication, these nanoporous membranes offer a highly tunable platform for applications that require high throughput, high surface area, homogeneous pore size, and varying material properties. And, with these readily tunable chemical and structural properties, block polymer membranes will allow for significant improvements in myriad applications. In this Review, we summarize the key advances, with a specific emphasis on the previous 5 years of work, that have allowed block polymer-based membranes to reach their current level of technology. Furthermore, we project how these state-of-art, self-assembled block polymer membrane technologies can be utilized in present-day and future application arenas. In this way, we aim to demonstrate that the rigorous work performed on block polymer-based membranes has laid a strong foundation that will allow these macromolecular systems to: (1) be major avenues of fundamental scientific research and (2) be parlayed into transferable technologies for the betterment of society in the imminent future. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41683. [ABSTRACT FROM AUTHOR]

ABSTRACT A carboxylic acid group was introduced on the polysulfone (PSF) membrane surface through a Friedel-Crafts reaction. Then, three kinds of poly(ethylene glycol) (PEG) derivatives were chosen to be immobilized on the PSF membrane surface via amide bonds. The membrane surface morphology, chemical composition, and hydrophilicity were investigated with scanning electron microscopy, attenuated total reflectance Fourier transform infrared spectroscopy, and water contact angle. The results indicate that PEG derivative immobilization effectively improved the antifouling properties of the PSF membranes. We found that prolonging the Friedel-Crafts reaction time or choosing the proper PEG derivative [methoxy poly(ethylene glycol) 550] could increase the surface hydrophilicity effectively and thus render the modified membranes better antifouling properties. The long-term ultrafiltration experiment demonstrated the improvement of recycling properties and the reliability of the surface modification process. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41870. [ABSTRACT FROM AUTHOR]

ABSTRACT To enhance the permeability, hydrophilicity, and antifouling properties of poly(vinyl chloride) (PVC) membranes, in this study, poly(ether glycol) methyl ether methacrylate (PEGMA) was grafted onto poly(ether sulfone) (PES) to first synthesize PES- g-PEGMA. Then, PES- g-PEGMA was blended with PVC (with blend ratios of PVC/PES- g-PEGMA that varied from 10 : 0 to 7 : 3) through the non-solvent-induced phase separation method to fabricate PVC/PES- g-PEGMA blend membranes. Shear viscosity and Fourier transform infrared-attenuated total reflection experiments showed that PVC/PES- g-PEGMA was a partially compatible system and that it was more compatible than a PVC/PES blending system. The contact angle, equilibrium water content, and X-ray photoelectron spectroscopy measurements confirmed that the PVC/PES- g-PEGMA blend membranes had a stronger hydrophilicity than the pure PVC membranes. Additionally, the results of this experiment also show that the PVC/PES- g-PEGMA blend membranes exhibited a higher permeability and superior antifouling properties than the pure PVC membranes, and the optimum blend ratio of the PVC/PES- g-PEGMA blend membranes was 7 : 3. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41726. [ABSTRACT FROM AUTHOR]

ABSTRACT A novel and simple but practical method for the preparation of modified poly(ether sulfone) (PES) membranes was provided by the in situ crosslinked copolymerization of sulfobetaine methacrylate (SBMA) and sodium p-styrene sulfonate (NaSS) in PES solution followed by a phase-separation technique. Then, semi-interpenetrating network membranes modified by the crosslinked copolymers of poly(sulfobetaine methacrylate- co-sodium p-styrene sulfonate) [P(SBMA- co-NaSS)] were prepared. The SBMA-containing copolymer-modified membranes showed improved protein antifouling properties with flux recovery ratios above 90%. Furthermore, the anticoagulant properties of the NaSS-containing copolymer-modified membranes were obviously enhanced; their activated partial thromboplastin time could be prolonged to about 115 s. Thus, the P(SBMA- co-NaSS) zwitterionic copolymer-modified membranes showed improved antifouling properties and blood compatibility and will provide wide choices for their specific applications. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41585. [ABSTRACT FROM AUTHOR]

ABSTRACT The role of the polymer interfacial area on free radical grafting of acrylic acid (AA) onto poly(vinylidenefluoride) (PVDF) was studied at 65°C using supercritical carbon dioxide (scCO2) as a solvent and swelling agent, benzoylperoxide (BPO) as chemical initiator and PVDF nanoparticles as polymer matrix. Under adopted conditions PVDF particles do not melt neither dissolve in the reaction medium and FTIR analyses performed on carefully washed nanoparticles confirmed the achievement of high grafting levels. The mass fraction of grafted AA increased with the grafting time and the BPO concentration while it decreased when the density of the fluid phase was enhanced. Collected results suggest that the grafting level obtained by free radical grafting of vinyl monomers onto solid polymer in scCO2 can be significantly enhanced by increasing the interfacial area of the matrix. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41541. [ABSTRACT FROM AUTHOR]

ABSTRACT The surface modification of a PES hollow fiber by UV photografting has been investigated in order to graft a dense polymer layer. The study focused on a UV photografting process, starting from a monomer solution, enabling the thickness and regularity of the grafted polymer to be followed. 2-(Acryloyloxy)ethyl trimethylammonium chloride was polymerized on the surface of the PES membrane. Modified membranes were characterized by SEM, FTIR spectroscopy, and liquid and gas permeability. A dense layer of poly(2-(acryloyloxy)ethyl trimethylammonium chloride) was obtained when a photoinitiator and a photocrosslinker were used. Polymerization of the ammonium material also occurred inside the pores of the membrane. With pretreatment and an increase of the irradiation time, the thickness of the grafted polymer decreased and gas permeability reached measurable levels. However, a CO2/N2 selectivity of around 1 was found which suggested the presence of defects in the grafted layer. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41514. [ABSTRACT FROM AUTHOR]

ABSTRACT Excellent biocompatible polymeric membranes were prepared by combining the antifouling property of poly(ethylene glycol) methyl ether (mPEG) and the anticoagulant property of poly(sodium p-styrene sulfonate) (PSS). Block copolymers of poly(ethylene glycol) methyl ether- b-poly(sodium p-styrene sulfonate) (mPEG- b-PSS) with different chain lengths were synthesized by ATRP using mPEG macroinitiator. The copolymers were then used to modify polyethersulfone (PES) membrane via layer-by-layer (LBL) self-assembly technology. The chemical compositions, surface morphologies and hydrophilicity of the modified membranes were characterized, indicating that the mPEG- b-PSS copolymers were successfully deposited on the membranes surfaces. Then, the blood compatibility and cytocompatibility of the modified membranes were systematically investigated. The results indicated that the mPEG- b-PSS copolymers could improve the hydrophilicity and the resistance to protein adsorption, and had great effect on suppressing platelet adhesion, prolonging clotting times, and improving cytocompatibility. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41245. [ABSTRACT FROM AUTHOR]

ABSTRACT In this article, poly(vinylidene fluoride) (PVDF) hollow fiber membrane and acrylic acid (AA) were co-irradiated by high-energy electron beam to introduce hydrophilic carboxylic groups on the membrane surface. Thermal capability, mechanical performance, pore size, and permeation property were investigated to determine the stability of the membrane pore structure before and after irradiation polymerization. The decomposition temperature, melting point, glass transition temperature, and breaking force of the PVDF- g-AA membrane increased slightly because of irradiation grafting polymerization. After 15 months of storage, the pore size distribution of the PVDF- g-AA membrane became smaller and more dispersive. The pure water flux and the rejection to bovine serum albumin of the PVDF- g-AA membrane increased significantly with the increase in hydrophilicity and decrease in pore size. The results indicated that the structure and properties of the PVDF hollow fiber membrane were stable after high-energy electron beam irradiation grafting polymerization, even after 15 months of storage. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41165. [ABSTRACT FROM AUTHOR]

ABSTRACT A novel coating technique, named as two-way coating (TWC), was explored to prepare hollow fiber composite (HFC) nanofiltration (NF) membrane through interfacial polymerization from piperazine (PIP) and trimesoyl chloride (TMC) on the lumen side of hollow fiber polysulfone ultrafiltration membrane with an effective membrane area of 0.4 m2. The optimum preparation conditions were systematically investigated and obtained as follows: PIP 0.023 mol/L, TMC 0.0057 mol/L, air blowing rate 2.7 m/s for 30 min after aqueous coating, aqueous coating pressure 0.1 MPa, organic solution flowing rate 0.32 m/s, and heat treating time 3 min. The resultant HFC membrane showed a high selectivity of divalent ion and monovalent ion. Salt rejections of MgSO4 and NaCl were 98.13 and 18.6% with the permeate flux of 32.6 and 40.2 L m−2 h−1 at 0.7 MPa, respectively. Field emission scanning electron microscopy images indicated that composite membrane prepared by TWC technique had a uniform active layer from the upper end to the bottom of the hollow fiber. And the salt rejection and permeate flux showed almost no difference between different membrane sections. Stability results suggested that good reproducibility could be obtained by TWC technique for the preparation of high-performance HFC NF membrane. The resultant NF membrane showed a high removal rate of chemical oxygen demand and chroma of landfill leachate which were approximately 100%. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41187. [ABSTRACT FROM AUTHOR]

ABSTRACT Fluorine-based amphiphobic coatings have been widely used in commercial textiles to provide water- and oil-repelling abilities. However, few reports from the literature survey have discussed the surface structural effects of the coated substrate on amphiphobicity. In this research, various thickness amphiphobic coatings based on mixed epoxy, tetraethylorthosilicate, and a particular alkoxysilane with fluorinated side chains (F-silane) were deposited on Grade 420 stainless steel plates. Film amphiphobicity is characterized by measuring the water and oil contact angles of the coating. Film morphology is examined using atomic force microscopy. The deposited films free of F-silane are thinner than 150 nm. The films become thick at high F-silane volume percentage with the surface cavities, ridges, and granules being masked out. On the addition of F-silane, the water contact angle of the deposited films increases up to 105° and then reaches a plateau of ∼ 107° with increasing F-silane. In contrast, the oil contact angle increases up to 60° at first and then slowly declines with the F-silane concentration. The total drop of oil contact angle by ∼ 20° was attributed to the masking out of surface features on film thickening. This indicates that the surface oleophobicity depends on surface structures. Therefore, improving surface amphiphobicity correlates with creating more refined multiscale surface structures during the industrial manufacturing process of steel plate, prior to surface modification by F-silane. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41003. [ABSTRACT FROM AUTHOR]

ABSTRACT We have developed a sequence-dependent synthesis of the amino-functionalized poly(ether sulfone) P2. The amino groups of P2 act as reactive sites toward epoxy resins. After curing P2 with diglycidyl ether of bisphenol A (DGEBA) and cresol novolac epoxy (CNE), we obtained the flexible, light-yellow, transparent, epoxy thermosetting films P2/DGEBA, and P2/CNE, respectively, having glass transition temperatures ( Tg) of 258 and 274°C, respectively. In addition, we also prepared a flexible film after condensation of the amino groups of P2 with the anhydride groups of 4,4′-oxydiphthalic anhydride (ODPA); after imidization at 300°C for 1 h, the resulting P2/ODPA thermosetting film possessed a value of Tg of 340°C. These three thermosetting films also exhibited flame retardancy with a UL-94 VTM-0 grade. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40980. [ABSTRACT FROM AUTHOR]

ABSTRACT Silk fibroin has long been used as implantable surgical sutures and it has acceptable mechanical properties and patency rates in animal models and in clinical end-uses. However, fibroin has been shown to be hemolytic and can cause damage to red blood cells. So to be used as an implantable vascular prosthesis its hemocompatibility needs to be improved. This study has taken two sequential steps to address this problem. First, to create a positively charged layer on the fibroin fibers' surface, a 1.5 and 2.5 bilayers polyelectrolyte surface deposition layer-by-layer technique was used with the positive counterion poly(allylamine hydrochloride) and the negative counterion poly(acrylic acid). Second, negatively charged low molecular weight heparin was then immobilized on these positively charged self-assembled surfaces. The presence of the heparin was confirmed with Alcian Blue staining and a toluidine blue assay, and the increased roughness and hydrophilicity of the modified surfaces were characterized by scanning electron microscopy, contact angle measurements, and atomic force microscopy. In addition, a negligible hemolytic effect, reduced protein adsorption, and a higher concentration of free hemoglobin measured by a kinetic clotting time test were found to be enhanced with the use of 2.5 bilayers compared to the 1.5 bilayers self-assembly technique. Given the success of these preliminary results, it is anticipated that this novel approach of surface modification and heparin immobilization will demonstrate long-term patency during future animal trials of small caliber silk fibroin vascular grafts. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40772. [ABSTRACT FROM AUTHOR]

A novel amphiphilic hydrogel based on poly(2-methyl-2-oxazoline)- b-poly(dimethyl siloxane) (PMeOx-PDMS) block copolymer was developed. First of all, PMeOx-PDMS macromonomer was synthesized by coupling mono-hydroxylated PMeOx with PDMS followed by end-capping with methacrylate group. The structures of each step were characterized by NMR and titration. After that, silicone hydrogels were prepared by UV-initiated copolymerization of PMeOx-PDMS macromonomer with monomers such as 2-hydroxyethyl methacrylate in the presence of a crosslinker. Measurements of the hydrogels' water contact angle, equilibrium water content, and tensile properties showed that the hydrogels possessed better hydrophilic surface, higher water content, and better ion permeability with the increase of the content of the macromonomer PMeOx-PDMS. Meanwhile, the tensile strength and Young's modulus of the hydrogels decreased slightly. Protein adsorption tests showed that the hydrogels had strong antifouling ability after the incorporation of PMeOx. This newly described hydrogel demonstrated attractive properties to serve as ophthalmic biomaterial. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39867. [ABSTRACT FROM AUTHOR]

ABSTRACT In this study, a random copolymer of poly(vinyl pyrrolidone- co-methyl methacrylate- co-acrylic acid) was synthesized via a one-pot reaction with the reversible addition-fragmentation chain-transfer method and was then blended with poly(ether sulfone) (PES) to prepare flat-sheet membranes that were expected to have anticoagulant and antifouling properties. The synthesized copolymer was characterized by Fourier transform infrared (FTIR) and NMR spectroscopy. The molecular weights and molecular weight distributions were determined by gel permeation chromatography. Elemental analysis was used to calculate the molar ratios of vinyl pyrrolidone (VP), methyl methacrylate (MMA), and acrylic acid (AA) in the copolymer. A liquid-liquid phase-inversion technique was used to prepare the copolymer-blended PES membranes. X-ray photoelectron spectroscopy and attenuated total reflectance-FTIR spectroscopy were used to investigate the copolymer on the membrane surfaces. Compared with the pristine PES membrane, the modified PES membranes showed improved hydrophilicity, low hemolysis ratios, decreased protein adsorption, and suppressed platelet adhesion. Furthermore, the thrombin time and activated partial thromboplastin time indicated that the blood compatibility of the modified PES membranes were improved. The results of the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and the cell morphology suggested that the cytocompatibility increased. In addition, the modified membranes showed good protein antifouling properties. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4284-4298, 2013 [ABSTRACT FROM AUTHOR]

Polypropylene (PP) was functionalized in the melt by grafting polar monomers using an internal mixer and a corotating twin-screw extruder. 2,5-Bis(tertbutylperoxy)-2,5-dimethylhexane (Luperox 101) and dicumyl peroxide (DP) were the used radical initiators. The polar monomers were itaconic acid (IAc), 2-octen-1-ylsuccinic anhydride (OY), 2-hydroxyethyl methacrylate (HEMA), and 3-allyloxy-1,2-propanediol (AP). Grafting was quantified by FTIR combined to Elemental Analysis. Grafting degree depends mainly on monomer and initiator natures and concentrations. Grafting degree maxima were 3.9, 2, 9.5, and 3.9 wt %, respectively, for IAc, OY, HEMA, and AP. Some properties of the modified PP were evaluated. Thermal analysis indicated that the polarity of PP increased by grafting reaction and size-exclusion chromatography showed that the grafting was not accompanied by a significant M w and viscosity decrease. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 [ABSTRACT FROM AUTHOR]

Poly(vinylidene fluoride) (PVDF) powders were grafted with N-vinyl pyrrolidone using the pre-irradiation induced graft polymerization technique. The effects of reaction time, absorbed dose, and monomer concentration on the degree of grafting were investigated, and the grafted PVDF powders were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, and differential scanning calorimetry. The grafted PVDF powders were also cast into microfiltration (MF) membranes via the phase-inversion method. The contact angle and water uptake were measured. The membrane morphology was studied by scanning electron microscopy, and the water filtration properties of the membranes were tested. The antifouling properties were determined through measurements of the recovery percentage of pure water flux after the MF membranes were fouled with bovine serum albumin solution. The results confirmed that the existence of poly( N-vinyl pyrrolidone) (PVP) graft chains improved the hydrophilicity and antifouling properties of the MF membranes cast from PVDF- g-PVP powders. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 [ABSTRACT FROM AUTHOR]

Novel charged membranes were prepared with sulfonated poly(ether ether ketone) (SPEEK). Methylsulfonic acid was used as solvent to accommodate the very low degree of sulfonation of the SPEEK. Membranes were prepared by immersion phase inversion method, using coagulation baths of different composition and temperature. Low molecular weight and negatively charged dye molecules were used as model solutes to test the nanofiltration (NF) performance of the membranes. Higher than 93% rejection of the two dye molecules, Rose Bengal and Reactive Brilliant Red, was observed at normal operating temperature. A permeate flux as high as 497 L m−2 h−1 and higher than 90% of solute rejection at 80°C was achieved in the NF of Reactive Brilliant Red aqueous solution, in contrast to a flux of 226 L m−2 h−1 and about 78% of solute rejection at the same temperature in the case of Rose Bengal solute. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 [ABSTRACT FROM AUTHOR]

A polyvinyl pyrrolidone terpolymer system is described that can be chemically cross-linked at moderate, 70-100°C, temperatures. The system has significant potential for development of durable long-lasting pyrrolidone coatings in a wide range of applications, particularly in water filtration membrane construction where leaching is an unresolved, serious problem. The synthesis of the terpolymer, poly( N-vinyl-2-pyrrolidone- co-vinyl acetate- co-glycidyl methacrylate), by free radical polymerization is described. The reactive features of this terpolymer are presented in the context of acidic anhydride curing. In a polar aprotic solvent, the terpolymer is reacted with poly(methyl vinyl ether- co-maleic acid) and cured thermally. Key aspects of the terpolymer synthesis and the acid anhydride cross-linking reaction using DSC, rheology, FTIR, and a small molecule model system to study the cross-linking chemistry are presented. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 [ABSTRACT FROM AUTHOR]

An intelligent photo-responsive spiropyran (SP)-contained surface that combines reversible wettability conversion with photochromic behavior was prepared on etched silicon substrates by atom transfer radical polymerization. The heterocyclic ring cleavage of SP moieties under UV irradiation leads to the change of the surface wettability and color. Water contact angle (CA) of the prepared surfaces change from 138.8° ± 1.3° to 42.7° ± 1.7° after 5 min under 365 nm UV irradiation and recover to its original state after 20 min of visible light irradiation, accompanied by the color change between yellowish and purple. To our knowledge, this result is the highest and fastest CA variation reported for surfaces containing SPs. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 [ABSTRACT FROM AUTHOR]

Poly(acrylic acid) (PAA) was used as an additive to fabricate blended polysulfone (PSF) ultrafiltration (UF) membranes. Hexanediamine was used as a crosslinking agent to react with PAA and formed an active surface with amine group. Then, an end carboxyl group methoxy polyethylene glycol (MPEG) was grafted on the membrane surface via an amidation reaction. Water contact angle measurement indicated that the surface hydrophilicity of PSF/PAA-blended membranes and MPEG-modified membranes remarkably increased. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR/FTIR) was used to confirm the existence of PAA in the blended membranes and the change of chemical composition. Membrane surface and cross-sectional morphologies were observed by scanning electron microscope. The flux of pure water increased slightly after modification, while the rejection to bovine serum albumin had no obvious change. The improvement of antifouling property for MPEG-modified membrane was accordant with the increase of PAA content in PSF/PAA-blended membranes. Protein UF experiments revealed that membrane fouling, especially irreversible membrane fouling, was remarkably reduced due to the incorporation of MPEG. The long-term protein UF experiment demonstrated the improvement of recycling property and the reliability of modification. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 [ABSTRACT FROM AUTHOR]

Lipase immobilization on asymmetric polysulfone (PS) membranes was done by physical adsorption and covalent coupling techniques. The glutaraldehyde (Glu) crosslink showed maximum immobilization (1.53 mg/cm2) on the hydrazine (Hz)-modified membrane surface. Lipase immobilization on the membrane was proved by different analytical tools (viz., X-ray diffraction, scanning electron microscopy). The hydrolase-immobilized enzyme marked its hydrolyzing ability to different oils (olive, palm, and castor oils). The hydrolysis yield (U/mg) for the different immobilized membranes was in the following order: Olive oil > Palm oil > Castor oil. The PS-Hz-Glu-lipase membrane showed maximum hydrolyzing ability for olive oil (62.37 U/mg) and minimum hydrolyzing ability for castor oil (38.11 U/mg). The low aptitude for the hydrolysis of castor oil was explained by the presence of ricinoleic acid in the main composition. The lowest affinity toward castor oil (Michaelis-Menten constant = 18.86 m M) also featured the same. The order of maximum reaction rate for the same membrane was as follows: Olive oil (64.5) > Palm oil (62.5) > Castor oil (41.6). The immobilized lipase on PS-Hz-Glu suffered only a 12.5% deterioration for olive oil after five cycles. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 [ABSTRACT FROM AUTHOR]

Surface Modifying Macromolecules (SMM) were used to alter the hydrophobicity of polyetherimide (PEI) hollow fiber membranes and the effects of three fabrication parameters, which are the mass fraction of PEI and SMM in the casting dope and air gap, on the properties of fabricated membranes were investigated by application of Response Surface Methodology (RSM). The fabricated membranes were characterized in terms of mean pore size ( r P,m), permeation rate of helium gas at 1 bar transmembrane pressure difference, membrane porosity, and contact angle of water with inner and outer surfaces of membrane. The regression models obtained for mean pore size and permeation rate have good statistical parameters and are accurate. The model for r P,m predicts that plot of r P,m versus air gap has a minimum point, whereas the plots of r P,m versus PEI (wt %) and SMM (wt %) have maximum points. The regression model developed for membrane porosity predicts that membrane porosity decreases when air gap increases. Since water was used as bore fluid, the model developed for inner surface contact angle has low accuracy but the model developed for outer surface contact angle predicts that contact angle increases with SMM concentration in dope solution but there is a maximum point versus air gap. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 [ABSTRACT FROM AUTHOR]

Chemical transformation of acrylic membranes with hydroxylamine hydrochloride (HA) was carried out to introduce amidoxime groups. It was found that the reaction conditions, such as reaction time, HA concentration and temperature influence the amidoxime content, significantly. A sharp enhancement in the amidoximation at 80°C was observed. The FTIR studies showed a significant loss of nitrile groups during amidoximation process. Optimum conditions for the amidoximation process were investigated. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 [ABSTRACT FROM AUTHOR]

The article focuses on a study which examined the surface modification of polypropylene microporous membranes (PPHFMMs) through the sequential photoinduced grafting polymerization of acrylic acid (AAc) and acrylamide (AAm). It notes the important role played by grafting density and the grafting chain length in the modified membranes' antifouling characteristics. Results of the study showed better filtration performances of modified membranes in the submerged membrane-bioreactor (SMBR).

The article discusses a study which investigated the sulfonation of bisphenol A polyetherimide (PEI) through a novel postsulfonation route using trimethylsilychlorosulfonate. Particular focus is given to the effect of electron withdrawing group in the sulfonated poly(arylene ethers) (SPAE) on sulfonation. Results of the study showed that the deactivation of bisphenol A unit has led to the improved reaction rate with polysulfone (PSU) compared to PEI.

The article discusses developments in several surface treatment processes of synthetic polymeric membranes. These include plasma treatment, polymer grafting and addition of surface-modifying molecules. Both hydrophilic and hydrophobic additives can be used in the preparation of polymeric membrane surfaces which can enhance the membrane selectivity and permeability. Research on antifouling membranes is also mentioned.

The article examines the effects of Tween-20 concentration as a hydrophilic surfactant additive in polyethersulfone/N,N-dimethyl-formamide casting solutions on the fundamental characteristics of the membranes. Scanning electron microscope and atomic force microscopy analysis were performed to examine the membrane morphology. It is noted that an increase in the concentration of Tween-20, the membrane morphology changes slowly from thin structure to long and wide structure.

The article explores chemical and physicochemical modification methods applied to boost the hydrophilicity of polysulfone/poly(ether)sulfone (PS/PES) nanofiltration membranes. These methods include bulk modification, surface modification, and blending. Bulk modification reportedly can be carboxylation, but the most frequently used approach is sulfonation. Surface modifications can be implemented by plasma treatment, grafting, and other methods when existing membranes are to be enhanced.

The article deals with a study, which applied the electrodialysis (ED) process to remove four different bivalent metal ions from their solutions. It was noted that at any fixed flow rate enhancement in applied potential causes a more reduction of salt. The study calculates the resultant current, percentage reduction in total dissolved solid, current efficiency, and energy consumption.