Amphiphilic ABA‐type triblock copolymers for the development of high‐performance poly(vinylidene fluoride)/poly(vinyl pyrrolidone) blend ultrafiltration membranes for oil separation

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 (FRR = 88%) and oil–water emulsion (FRR = 95%) 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. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45132.     

Amphiphilic poly(vinyl chloride)‐g‐poly[poly(ethylene glycol) methylether methacrylate] copolymer for the surface hydrophilicity modification of poly(vinylidene fluoride) membrane

In this study, a comblike amphiphilic graft copolymer containing poly(vinyl chloride) (PVC) backbones and poly(oxyethylene methacrylate) [poly(ethylene glycol) methylether methacrylate (PEGMA)] side chains was facilely synthesized via an atom transfer radical polymerization method. Secondary chlorines in PVC were used as initial sites to graft a poly[poly(ethylene glycol) methylether methacrylate] [P(PEGMA)] brush. The synthesized PVC‐g‐P(PEGMA) graft copolymer served as an efficient additive for the hydrophilicity modification of the poly(vinylidene fluoride) (PVDF) membrane via a nonsolvent‐induced phase‐inversion technique. A larger pore size, higher porosity, and better connectivity were obtained for the modified PVDF membrane; this facilitated the permeability compared to the corresponding virgin PVDF membrane. In addition, the modified PVDF membrane showed a distinctively enhanced hydrophilicity and antifouling resistance, as suggested by the contact angle measurement and flux of bovine serum albumin solution tests, respectively. Accordingly, the PVC‐g‐P(PEGMA) graft copolymer was demonstrated as a successful additive for the hydrophilicity modification, and this study will likely open up new possibilities for the development of efficient amphiphilic PVC‐based copolymers for the excellent hydrophilicity modification of PVDF membranes. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Amphiphilic poly(ether sulfone) membranes for oil/water separation: Effect of sequence structure of the modifier

Oil‐contaminated wastewater threatens our environment and health thus novel membrane materials with low or nonfouling properties are an immediate need for oily wastewater treatment in a cost‐effective and environmentally friendly manner. In this study, three types of amphiphilic random, gradient, and block copolymers with similar molecular weights and chemical compositions, based on poly(ethylene glycol) methyl ether methacrylate (PEGMA) and 3,3,4,4,5,5,6,6,7,7,8,8,8‐tridecafluorooctyl acrylate (TFOA), were synthesized by the reversible addition‐fragmentation chain transfer (RAFT) method. The amphiphilic Poly(ether sulfone) membranes were then fabricated by blending with these copolymers via a facile coupled process of nonsolvent induced phase separation and surface segregation. Accompanying the phase inversion process of polymer matrix, the hydrophilic and hydrophobic segments in the amphiphilic modifiers would migrate and immobilize onto the membrane surfaces. This surface segregation process leaded to a chemical heterogeneous membrane surface comprising both hydrophilic PEGMA and low surface energy PTFOA brushes, which was confirmed by X‐ray photoelectron spectroscopy (XPS) and surface wettability analyses. Oil‐in‐water emulsion filtration test of the membranes displayed a lower permeate flux decline and a higher flux recovery (as high as 99.8%), establishing their considerably elevated antifouling properties. Additionally, cyclic oil/water separation and long‐term underwater immersion tests demonstrated that the as‐prepared membranes modified by these amphiphilic additives possessed excellent antifouling stabilities. © 2016 American Institute of Chemical Engineers AIChE J, 63: 739–750, 2017     

Preparation of hydrophilic polysulfone porous membrane by use of amphiphilic cellulose

A cellulose‐based amphiphilic co‐polymer with grafted myristyl groups was synthesized and used as an additive to modify polysulfone (PSf) membranes. Fourier transform infrared (FTIR) spectroscopy and Solid‐state cross polarization magic angle spinning carbon‐13 nuclear magnetic resonance (CP/MAS ¹³C NMR) spectroscopy were used to characterize the structure of the synthesized amphiphilic cellulose. The good compatibility between amphiphilic co‐polymer and PSf was confirmed by differential scanning calorimetry (DSC). Scanning electron microscopy (SEM) was conducted to inspect morphology of the membrane. Furthermore, Thermal performance was indicated by thermogravimetric analysis (TGA). Contact angle, flux and retention behavior were also measured in this work. The structural similarity enhanced compatibility among components by introducing flexible alkyl groups. According to the findings obtained from characterization, better compatibility of cellulose with PSf was achieved after amphiphilic treatment. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41664.     

Amphiphilic ABA copolymers used for surface modification of polysulfone membranes, Part 1: Molecular design, synthesis, and characterization

Two kinds of novel amphiphilic ABA copolymers, which are suitable for surface modification of polysulfone membranes, were successfully synthesized via the atom transfer radical polymerization (ATRP) technique, using a bromo-terminated difunctional polysulfone as macroinitiator. Firstly, the difunctional polysulfone macroinitiator was prepared by esterifying the phenolic end groups of polysulfone to α-haloesters. Secondly, the macroinitiator was used to initiate the polymerization of poly(ethylene glycol) methyl ether methacrylate (PEGMA) and 3-O-methacryloyl-1,2:5,6-di-O-isopropylidene-d-glucofuranose (MAIpG), resulting in two kinds of ABA copolymers, i.e., P(PEGMA)-b-PSF-b-P(PEGMA) and PMAIpG-b-PSF-b-PMAIpG, respectively. In the case of PMAIpG-b-PSF-b-PMAIpG, the isopropylidenyl groups of the protected sugar residues were removed by acidolysis treatment, thus the amphiphilic ABA copolymer, PMAG-b-PSF-b-PMAG, was obtained. The resultant copolymers were characterized by FT-IR, ¹H NMR, GPC, and TGA. Semipermeable polysulfone membranes prepared via the standard immersion precipitation phase inversion process, using the synthesized amphiphilic ABA copolymers as additives, display enhanced hydrophilicity and protein resistance compared to unmodified polysulfone membranes.     

Preparation and characterization of poly(vinyl chloride)‐graft‐acrylic acid membrane by electron beam

Poly(vinyl chloride) (PVC) was irradiated by electron beam in vacuum at 20 KGy to produce living free radicals, and then reacted with acrylic acid (AA) in solution to obtain the PVC‐g‐AA copolymers. The copolymers were characterized by Fourier transform infrared spectroscopy. Porous membranes were prepared from copolymers by the phase inversion technique. The morphology of PVC‐g‐AA membranes was studied by field emission scanning electron microscopy. The mean pore size and pore size distribution were determined by a mercury porosimeter. The mean pore size was 0.19 μm, and the bulk porosity was 56.02%. The apparent static water contact angle was 89.0°. The water drop penetration rate was 2.35 times to the original membrane. The maximum stress was 4.10 MPa. Filtration experiments were carried out to evaluate the fouling resistance of the PVC‐g‐AA membrane. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Facile surface modification of PVDF microfiltration membrane by strong physical adsorption of amphiphilic copolymers

To endow the surface of poly(vinylidene fluoride) (PVDF) microfiltration (MF) membranes with hydrophilicity and antifouling property, physical adsorption of amphiphilic random copolymers of poly(ethylene glycol) methacrylate (PEGMA) and poly(methyl methacrylate) (PMMA) (P(PEGMA‐r‐MMA)) onto the PVDF membrane was performed. Scanning electron microscopy (SEM) images showed that the adsorption process had no influence on the membrane structure. Operation parameters including adsorption time, polymer concentration, and composition were explored in detail through X‐ray photoelectron spectroscopy (XPS), static water contact angle (CA), and water flux measurements. The results demonstrated that P(PEGMA‐r‐MMA) copolymers adsorbed successfully onto the membrane surface, and hydrophilicity of the PVDF MF membrane was greatly enhanced. The antifouling performance and adsorption stability were also characterized, respectively. It was notable that PVDF MF membranes modified by facile physical adsorption of P(PEGMA₅₈‐r‐MMA₃₃) even showed higher water flux and better antifouling property than the commercial hydrophilic PVDF MF membranes. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3112–3121, 2013     

Fabrication of polysulfone asymmetric hollow‐fiber membranes by coextrusion through a triple‐orifice spinneret

Polysulfone (PSf) asymmetric hollow‐fiber membranes, which have a dense outer layer but a loose inner layer, were tentatively fabricated by coextrusion through a triple‐orifice spinneret and a dry/wet‐phase inversion process. Two simple polymer dopes were tailored, respectively, for the dense outer layer and the porous inner layer according to the principles of the phase‐inversion process. By adjusting the ratio of the inner/outer extrusion rate, the hollow‐fiber membranes with various thicknesses of outer layers were achieved. The morphology of the hollow‐fiber membranes was exhibited and the processing conditions and the water permeability of the membrane were investigated. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 259–266, 2004     

Solubility parameter estimation and phase inversion modeling of bentonite-doped polymeric membrane systems

Effects of bentonite concentration on morphology and permeation characteristics of bentonite-doped polysulfone membranes were investigated. Solubility sphere for bentonite was constructed to estimate its solubility parameter. Thermodynamic modeling of phase inversion of this system was carried out using Flory–Huggins theory. The trade-off between thermodynamic and kinetic parameters was used to predict the membrane morphology for bentonite concentration varying from 0 to 5 wt %. The porosity of bentonite-doped membranes decreased up to 3 wt % that increased thereafter. Morphological analysis showed dense cross section with finger-like macrovoids at 3 wt % beyond which it changed to honeycomb structure with large circular voids. Permeability of 3 wt % membrane was the lowest (5.6 × 10⁻¹² m/Pa s) with 95% bovine serum albumin rejection. Contact angle of the membranes decreased from 83 to 66° with bentonite addition making the membrane more hydrophilic. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48450.     

Preparation and performance evaluation of poly (ether-imide) incorporated polysulfone hemodialysis membranes

Biocompatible Polysulfone (PSf) hemodialysis membranes were prepared by phase inversion technique using poly (ether-imide) (PEI) as the modification agent and Polyethylene glycol (PEG-200) as the pore former. The effect of PSf/PEI blend ratio on the morphology, hydrophilicity, water content, porosity, glass transition temperature, mechanical strength, biocompatibility and permeation rate of the prepared membranes were studied and were found to be improved significantly by the incorporation of PEI in the dope solution. The scanning electron microscopy (SEM) studies revealed that, incorporation of PEI resulted in the formation of spongy sub-layer and increased the connectivity of pores between sub-layer and bottom layer. The water content and permeation rate of the membranes of PSf/PEI blend membranes were increased considerably indicating the enhancement of hydrophilicity and it was supported by lower contact angle values of the blend membranes. The existence of single well defined Tg over entire composition established the compatibility between the components in blend membranes. The biocompatibility of membranes was investigated through protein adsorption, platelet adhesion and thrombus formation on the membrane surface. Anticoagulant activity of PSf/PEI blend membranes was evaluated by measuring the activated partial thrombin time (APTT), prothrombin time (PT), thrombin time (TT) and fibrinogen time (FT). The results revealed that antithrombogenicity of PSf/PEI blend membranes was increased significantly. The efficiency of these membranes in removal of urea, creatinine and vitamin B₁₂ were studied and found to be improved for blend membranes. Thus, it is worth mentioning to note that, the biocompatible PSf/PEI blend membranes prepared in this study would offer immense potential in hemodialysis.     

An investigation of lithium ion conductivity of copolymers based on P(AMPS-co-PEGMA)

In this work, a series of novel lithium ion-conducting copolymer electrolytes based on 2-acrylamido-2-methyl-1-propane sulfonic acid (AMPS) and poly(ethyleneglycol) methacrylate (PEGMA) were produced and characterized. The copolymers were synthesized by free-radical polymerization of the corresponding monomers with three different feed ratios to form P(AMPS-co-PEGMA)-based electrolytes. After the polymerization, AMPS units of the copolymers were lithiated via ion exchange. The characterization of the electrolytes was done by ¹H-NMR, FTIR, differential scanning calorimetry (DSC), thermogravimetric analysis, X-ray diffraction, scanning electron microscopy (SEM), and impedance analyzer. The copolymers were thermal stable approximately to 200 °C. Single T_g transitions in DSC curves verified the homogeneity as well as amorphous characteristics. SEM further confirmed the homogeneity of the electrolytes. The lithium ion conductivity of these new polymer electrolytes was studied by impedance dielectric impedance analyzer and the effect of PEGMA contents onto the ionic conductivity of these copolymer electrolytes were investigated. It was observed that the temperature dependence of ionic conductivity was interpreted over Vogel Tammann Fulcher model. The Li ion conductivity increased by PEGMA content and S3 has maximum conductivity of 3 × 10⁻³ mS cm⁻¹ at 100 °C. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47798.     

Fabrication of polysulfone nanocomposite membranes with silver‐doped carbon nanotubes and their antifouling performance

In this study, polysulfone (PSf)/silver‐doped carbon nanotube (Ag‐CNT) nanocomposite membranes were prepared by a phase‐inversion technique; they were characterized and evaluated for fouling‐resistant applications with bovine serum albumin (BSA) solutions. Carbon nanotubes were doped with silver nanoparticles via a wet‐impregnation technique. The prepared Ag‐CNT nanotubes were characterized with scanning electron microscopy (SEM)/energy‐dispersive X‐ray spectroscopy, X‐ray diffraction, Raman spectroscopy, and thermogravimetric analysis. The fabricated flat‐sheet PSf/Ag‐CNT nanocomposite membranes with different Ag‐CNT loadings were examined for their surface morphology, roughness, hydrophilicity, and mechanical strength with SEM, atomic force microscopy, contact angle measurement, and tensile testing, respectively. The prepared composite membranes displayed a greater rejection of BSA solution (≥90%) and water flux stability during membrane compaction with a 10% reduction in water flux values (up to 0.4% Ag‐CNTs) than the pristine PSf membrane. The PSf nanocomposite membrane with a 0.2% Ag‐CNT loading possessed the highest flux recovery of about 80% and the lowest total membrane resistance of 56% with a reduced irreversible fouling resistance of 21%. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44688.     

Preparation,surface wetting properties,and protein adsorption resistance of well‐defined amphiphilic fluorinated diblock copolymers

Novel well‐defined amphiphilic fluorinated diblock copolymers P(PEGMA‐co‐MMA)‐b‐PC₆SMA were synthesized successfully by RAFT polymerization and characterized by FTIR, ¹HNMR and GPC. For copolymer coatings, static contact angles, θ, with water (θ_water ≥ 109.5^°) and n‐hexadecane (θ_hexadecane ≥ 68.9^°) pointed to the simultaneous hydrophobic and lipophobic characteristics of the copolymer surfaces. Dynamic contact angle measurements indirectly demonstrated that copolymer films underwent surface reconstruction upon contact with water, which results in a surface with surface coverage of polar PEG units. Moreover, the distinct nanoscale microphase segregation structures were proved by atomic force microscopy (AFM) images. Finally, using bovine serum albumin (BSA–FITC) as the model protein, copolymers exhibited excellent protein adsorption resistance. It is believed that the combination of surface reorganization and nanometer‐scale microphase segregation structure endows the excellent protein resistance for amphiphilic fluorinated copolymers. These results provide deeper insight of the effect of surface reconstruction and microphase segregation on the protein adsorption behaviors, and these amphiphilic fluoropolymers can expect to have potential applications as antifouling coatings in the field of marine and biomedical. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41167.     

Enhanced hydrophilic polysulfone hollow fiber membranes with addition of iron oxide nanoparticles

Membranes are at the heart of hemodialysis treatment functions to remove excess metabolic waste such as urea. However, membranes made up of pure polymers and hydrophilic polymers such as polyvinylpyrrolidone suffer problems of low flux and bio‐incompatibility. Hence, this study aimed to improve polysulfone (PSf ) membrane surface properties by the addition of iron oxide nanoparticles (IONPs ). The membrane surface properties and separation performance of neat PSf membrane and membrane filled with IONPs at a loading of 0.2 wt% were investigated and compared. The membranes were characterized in terms of morphology, pure water permeability (PWP ) and protein rejection using bovine serum albumin (BSA ). A decrease in contact angle value from 66.62° to 46.23° for the PSf /IONPs membrane indicated an increase in surface hydrophilicity that caused positive effects on the PWP and BSA rejection of the membrane. The PWP increased by 40.74% to 57.04 L m^?2 h^?1 bar^?1 when IONPs were incorporated due to the improved interaction with water molecules. Furthermore, the PSf /IONPs membrane rejected 96.43% of BSA as compared to only 91.14% by the neat PSf membrane. Hence, the incorporation of IONPs enhanced the PSf hollow fiber membrane hydrophilicity and consequently improved the separation performance of the membrane for hemodialysis application. © 2017 Society of Chemical Industry     

Cyclodextrin‐dendrimer functionalized polysulfone membrane for the removal of humic acid in water

Commercial polysulfone (PSf) membranes were crosslinked with a β‐cyclodextrin‐poly (propyleneimine) (β‐CD‐PPI) conjugate which had β‐CD pendant arms using trimesoyl chloride (TMC) by interfacial polymerization. The morphology and physicochemical properties of the nanofiltration membranes were characterized using Fourier transform infrared/attenuated total reflectance (FT‐IR/ATR) spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), and cross‐flow filtration system. Water‐contact angle, water‐intake capacity, and rejection capacities of the membranes were evaluated. The β‐CD‐G4 (generation 4)‐PPI‐PSf and β‐CD‐G3 (generation 3)‐PPI‐PSf membranes both exhibited high humic acid rejection of 72% as compared to the commercial PSf which exhibited 57%. The modified membranes were also more hydrophilic (36° to 41°) than PSf (76°). These results suggest that β‐CD‐PPI nanostructures are promising materials for the synthesis of membranes for the removal of humic acid from water. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4428–4439, 2013     

Fabrication of antifouling membranes by blending poly(vinylidene fluoride) with cationic polyionic liquid

Membrane fouling problem is now limiting the rapid development of membrane technology. A newly synthesized cationic polyionic liquid (PIL) [P(PEGMA-co-BVIm-Br)] was blended with poly(vinylidene fluoride) (PVDF) to prepare antifouling PVDF membranes. The PVDF/P(PEGMA-co-BVIm-Br) exhibited an increased surface hydrophilicity, the water contact angle was reduced from 77.8° (pristine PVDF) to 57.9°. More porous membrane structure was obtained by adding PIL into the blending polymers, as high as 478.0 L/m²·h of pure water flux was detected for the blend PVDF membrane in comparison with pristine PVDF (17.2 L/m²·h). Blending of the cationic PIL with PVDF gave a more positive surface charge than pristine PVDF membrane. Blend membranes showed very high rejection rate (99.1%) and flux recovery rate (FRR, 83.0%) to the positive bovine serum albumin (BSA), due to the electrostatic repulsion between the membrane surface and proteins. After three repeated filtration cycles of positive BSA, the blend PVDF membranes demonstrated excellent antifouling performance, the permeation flux of the membranes was recovered very well after a simple deionized water washing, and as high as 70% of FRR was obtained, the water flux was maintained at above 350 L/m²·h. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48878.     

Studies on Cellulose Acetate/Low Cyclic Dimmer Polysulfone Blend Ultrafiltration Membranes and their Applications

Abstract

Flat sheet ultrafiltration membranes from cellulose acetate (CA)/low cyclic dimer polysulfone (LCD PSf) were prepared by a phase inversion method. N, N′‐Dimethyl formamide and different molecular weight of polyethylene glycol (PEG 200, PEG 400, and PEG 600) were used as solvent and pore‐forming additive, respectively. The membranes were characterized in terms of pure water flux, water content, porosity, membrane hydraulic resistance, and morphology. The pure water flux was found to reach the highest value of 181.82 Lm^?2h^?1 at 5 wt.% PEG of 600 molecular weight and 10 wt.% LCD PSf content in the blended solution for membrane preparation. SEM micrographs indicated that the addition of PEG into the CA/LCD PSf solution changes the inner structure of the membrane. The influence of filtration time and applied pressure on membrane permeability was examined by copper/polyethylenimine complex rejection studies. With increase in filtration time, the rejection of the copper/polyethylenimine complex decreased and the results were discussed.     

Synthesis of well‐defined amphiphilic block copolymers via AGET ATRP used for hydrophilic modification of PVDF membrane

A well‐defined amphiphilic block copolymer consisting of a hydrophobic block poly(methyl methacrylate) (PMMA) and a hydrophilic block poly[N,N–2‐(dimethylamino) ethyl methacrylate] (PDMAEMA) was synthesized by activator generated by the electron transfer for atom transfer radical polymerization method (AGET ATRP). Kinetics study revealed a linear increase in the graph concentration of PMMA‐b‐PDMAEMA with the reaction time, indicating that the polymer chain growth was consistent with a controlled process. The gel permeation chromatography results indicated that the block copolymer had a narrow molecular weight distribution (Mw/Mn = 1.42) under the optimal reaction conditions. Then, poly(vinylidene fluoride) (PVDF)/PMMA‐b‐PDMAEMA blend membranes were prepared via the standard immersion precipitation phase inversion process, using the block copolymer as additive to improve the hydrophilicity of the PVDF membrane. The presence and dispersion of PMMA‐b‐PDMAEMA clearly affected the morphology and improved the hydrophilicity of the as‐synthesized blend membranes as compared to the pristine PVDF membranes. By incorporating 15 wt % of the block copolymer, the water contact angle of the resulting blend membranes decreased from pure PVDF membrane 98° to 76°. The blend membranes showed good stability in the 20 d pure‐water experiment. The bovine serum albumin (BSA) absorption experiment revealed a substantial antifouling property of the blend membranes in comparison with the pristine PVDF membrane. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42080.     

Surface modification of linear low‐density polyethylene film by amphiphilic graft copolymers based on poly(higher α‐olefin)‐graft‐poly(ethylene glycol)

In this article, a series of amphiphilic graft copolymers, namely poly(higher α‐olefin‐co‐para‐methylstyrene)‐graft‐poly(ethylene glycol), and poly(higher α‐olefin‐co‐acrylic acid)‐graft‐poly(ethylene glycol) was used as modifying agent to increase the wettability of the surface of linear low‐density polyethylene (LLDPE) film. The wettability of the surface of LLDPE film could be increased effectively by spin coating of the amphiphilic graft copolymers onto the surface of LLDPE film. The higher the content of poly(ethylene glycol) (PEG) segments, the lower the water contact angle was. The water contact angle of modified LLDPE films was reduced as low as 25°. However, the adhesion between the amphiphilic graft copolymer and LLDPE film was poor. To solve this problem, the modified LLDPE films coated by the amphiphilic graft copolymers were annealed at 110° for 12 h. During the period of annealing, heating made polymer chain move and rearrange quickly. When the film was cooled down, the alkyl group of higher α‐olefin units and LLDPE began to entangle and crystallize. Driven by crystallization, the PEG segments rearranged and enriched in the interface between the amphiphilic graft copolymer and air. By this surface modification method, the amphiphilic graft copolymer was fixed on the surface of LLDPE film. And the water contact angle was further reduced as low as 14.8°. The experimental results of this article demonstrate the potential pathway to provide an effective and durable anti‐fog LLDPE film. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis of poly(4, 4′-biphenylene sulfonyl succinamide)-polysulfone blend membranes for removal of toxic metal ions from water

A novel polymer poly(4,4′-biphenylene sulfonyl succinamide) (PBSS) was synthesized via polycondensation reaction. Succinyl chloride and 4-aminophenyl sulfone were used as reactive monomers and anhydrous AlCl₃ was used as a catalyst. Both polysulfone (PSf) and PBSS were dissolved in N-methyl-2-pyrrolidone (NMP) at different compositions to obtain a homogeneous solution to fabricate PSf-PBSS blend membranes. The structure of PBSS was characterized by ATR-IR and ¹H-NMR spectroscopy. Thermal properties of PBSS were analyzed by TGA-DTA. Mechanical properties and morphology of blend membranes were analyzed by universal testing machines and field emission scanning electron microscope, respectively. The hydrophilicity of blend membranes with respect to the concentration of PBSS was studied by contact angle and water uptake studies. Upon blending, the hydrophilicity of PSf-PBSS membranes drastically increased due to the presence of large number of amide and sulfonyl groups in the matrix. The blend membranes exhibited significant increase in water flux from 100 L m⁻² h to 650 L m⁻² h⁻¹, and rejection of 100% for Pb(II) and 80% for both Cd(II) and As(III) toxic heavy metal ions. The hydrophilic nature of  CO NH and inter and intramolecular hydrogen bonding among PBSS polymer chains dispersed within rigid PSf matrix imparts softness, amide and sulfonyl groups enhance interconnected porosity and hydrophilicity of blend membranes. Hence, PBSS may serve as a low-cost novel polymeric additive for water purification and separation membrane applications. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48254.