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Silver nanoparticles were successfully synthesized from AgNO3 through a reliable, eco-friendly and simple green route using Paederia foetida L. leaf extract as a reducing cum stabilizing agent. UV-Visible Spectroscopy, dynamic light scattering, atomic force microscopy, transmission electron microscopy, and X-ray diffraction analysis were used for characterization of silver nanoparticles. The synthesized silver nanoparticles were spherical in shape with size range of 4–15 nm. The nanoparticles were face-centered cubic crystal structure. The adopted technique for silver nanoparticle synthesis is suitable for large-scale production. The as-prepared silver nanoparticles revealed excellent antibacterial activity against different gram classes of bacteria and would be a promising candidate for various pharmaceutical, biomedical, and environmental applications.

Photocatalyst, lead sulfide (PbS)-intercalated layer perovskite-type compound (K2La2Ti3O10), was synthesized via ion-exchange reaction, butylamine pillaring and sulfuration processes under the assistance of the microwave irradiation. The structure of the photocatalysts was determined by means of powder X-ray diffraction, scanning electron microscope, ultraviolet-visible diffuse reflection spectra and photoluminescence measurement. And the photocatalytic activity of the composite compound for hydrogen production was also investigated. The experimental results showed that the intercalation of PbS in the layered space of K2La2Ti3O10 greatly improved the absorption edge and the photocatalytic activity. Hydrogen production of the PbS–K2La2Ti3O10 was 127.19 mmol/(g cat) after 3 h irradiation of ultraviolet light.

The effect of molecular weight of poly(vinyl alcohol) (PVA) and sodium chloride on the gelation temperature of methylcellulose (MC) was studied with the objective to develop a MC based formulation for sustained delivery of ketorolac tromethamine a model ophthalmic drug. Pure MC showed sol-gel transition at 61.2 °C. In order to reduce the gelation temperature of MC and to increase the drug release time, PVA was used. Different techniques such as test tube tilting method, UV-vis spectroscopy, viscometry and rheometry were used to measure gelation temperature of all the binary combinations of MC and PVA. It was observed that the gelation temperature of MC was reduced with the addition of 4% PVA and also the extent of reduction of the gelation temperature of MC was dependent on the molecular weight of PVA. The strong interactions between MC and PVA molecules were established using Fourier transform infrared spectroscopy. To study the in vitro drug release properties of the MC-PVA binary combinations, 6% sodium chloride was used to reduce the gelation temperature further up to physiological temperature. It was observed that the drug release time increased from 5 to 8h with the increase of molecular weight of PVA from 9×10(3) to 1.3×10(5) and this was due to the higher viscosity, better gel strength and greater interactions between the drug and PVA molecules in case of PVA (1.3×10(5)) compared to PVA (9×10(3)). In order to have an idea about the nature of interactions between the functional moieties of the drug and the polymer unit of PVA, a theoretical study was carried out.

Electrospun nanofiber membranes consisting of poly(vinylidene fluoride) (PVDF) blended with clay nanocomposites were prepared and tested in this paper for direct contact membrane distillation (DCMD) applications. Various compositions of PVDF–clay nanocomposite nanofiber membranes (NNMs) were prepared and characterized by water contact angle, Fourier transform infrared spectroscopy, differential scanning calorimetry, scanning electron microscopy and investigated for DCMD. The incorporation of clay nanocomposites increase the hydrophobicity of the membranes, which increase as the concentration of clay nanocomposite increases in the mixture. The highest water contact angle achieved was 154.20 ± 3.04°. The melting point of the PVDF–clay electrospun nanofiber membrane increases with the increasing concentration of clay indicating that the clay particles influence the crystallization process of the nanocomposite membrane. The PVDF–clay NNMs showed improved performance in DCMD applications and provide a way to prevent pore wetting in DCMD process.

A novel surface modified polyetherimide (PEI) hollow fiber membrane was fabricated via dry–wet phased inversion process where the spinning dope contains Surface Modifying Macromolecule (SMM). The surface modified membrane exhibited large pore size, higher effective surface porosity, contact angle and porosity but lower Liquid Entry Pressure of water compared to polyetherimide hollow fiber membrane without SMM. The performance of surface modified membrane in contactor application for gas separation process was evaluated based on CO 2 absorption process using water as absorbent and pure CO 2 and 20:80 CO 2 /CH 4 gas mixture. The results show that surface modified membranes have superior performance compared to commercial and in-house made hydrophobic membranes such as polypropylene and polytetrafluoroethylene, e.g., in the case of pure CO 2 in the shell side and distilled water in the lumen side, the surface modified PEI membrane shows 72% higher absorption flux than commercial membrane contactor, Celgard MiniModule® 0.75X5 which is made of polypropylene membranes, when the liquid velocity is 0.4 m s −1 .

Polyvinylidene fluoride (PVDF) ultrafiltration membranes were modified using a new type of hydrophilic polyurethane additive, called L2MM. During phase inversion L2MM migrates to the membrane surface and functions as both a pore former and surface modifier. L2MM improved the surface hydrophilicity and significantly increased the PVDF membrane's pure water permeation (PWP) rate. PVDF membranes were modified with two L2MMs: L2MM(PEG-600) and L2MM(PEG-200). PWP tests, contact angle measurements, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and atomic force microscopy (AFM) were used to assess the impact of L2MM type, L2MM concentration and PVDF concentration on the performance and characteristics of modified PVDF membranes. XPS analysis and contact angle measurements indicated that the L2MM migrated to the membrane surface and the contact angle decreased by up to 19%. SEM and AFM images were used to investigate the relation between surface morphology and ultimate performance. The L2MMs had a significant effect on flux; increasing the L2MM concentration improved membrane PWP fluxes up to a maximum with further increases resulting in flux decreases. Both L2MM(PEG-200) and L2MM(PEG-600) increased the final PWP flux of modified PVDF membranes up to 6.5 times that of the control membranes. Furthermore, L2MM(PEG-200) increased the 100 kDa polyethylene oxide (PEO) separation from 88 to 96% compared to the control membrane.

We have investigated electrical transport properties of the composite of multiwall carbon nanotubes–polypyrrole–polyvinyl alcohol. Samples are prepared in an in situ chemical oxidative method and they are characterized by X-ray diffraction, field emission scanning electron microscope to understand their structure and morphology, respectively. Mechanism of electrical transport is done below room temperature (77–300 K) in presence and absence of magnetic field up to 1 T. Samples are following both one dimensional Mott's variable range hopping and tunneling theory. Forward interference model is used to explain the mechanism of magnetic field dependent conductivity. The real part of AC conductivity follows universal dielectric response σ′ (f) ∞ fS. The universal dielectric response parameter s varies with temperature according to correlated barrier hopping model. The variation of real part of complex impedance with frequency can be described in terms of Maxwell Wagner effect. The positive variation of AC conductivity can be explained in terms of grain and grain boundary contribution of the samples. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers

Integrally skinned asymmetric membranes for the separation of O2 and N2 were fabricated by the phase inversion technique from polysulfone, polyetherimide, and polyimide. Two types of surface modifying macromolecules (SMMs) including hydrophilic SMM (LSMM) and charged SMM (cSMM) were synthesized and blended with the casting solution to modify the membrane surface. The cast film was then immersed in the first coagulant alcohol (methanol, ethanol, or isopropanol) for a predetermined period, before being immersed in the second coagulant (water). The SMMs used in these experiments were laboratory synthesized by the two-step process of polyurethane prepolymer synthesis and end capping, before being characterized by differential scanning calorimetry. Their molecular structure was determined from the molecular weight obtained by gel permeation chromatography. The membranes were characterized by contact angle measurement and O2 and N2 gas permeation performance. Attempts were made to interpret the gas permeation data by delayed demixing affected by solubility parameters of polymer, solvent, and nonsolvent. Furthermore, the permeation performance of cSMM membranes was interpreted by the solvation of the charged sulfonate groups present in cSMM. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

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 (rP,m), permeation rate of helium gas at 1 bar transmembrane pressure difference, membrane poros- ity, 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 statis- tical parameters and are accurate. The model for rP,m pre- dicts that plot of rP,m versus air gap has a minimum point, whereas the plots of rP,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. V C 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123: 2812- 2827, 2012

In this article an attempt was made to fabricate defect-free asymmetric polysulfone (PSf) membranes for the separation of oxygen and nitrogen. The approach is based on the enhanced delayed demixing by blending surface modifying macromolecules (SMMs) in the casting solution and by immersing the cast film in isopropanol for a certain period before it is immersed in water. Different SMMs, including hydrophobic and charged SMMs, were synthesized, characterized, and blended to the host PSf. It was found that the charged SMM could indeed contribute to the removal of defective pores from the skin layer and enhancement of oxygen/nitrogen selectivity. The experimental results were further interpreted based on the shift of the phase boundary line on the polymer/solvent/nonsolvent triangular diagram, which occurred when SMMs were blended to PSf, due to the change in the polymer/nonsolvent interaction. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

The present contribution provides detailed information about the development of antifouling novel thin-film-composite (TFC) membranes for mostly water purification with special emphasis on seawater desalination in particular. The novel membranes were prepared by incorporating in-situ hydrophilic surface modifying macromolecules (iLSMM) into the TFC membranes, rendering the surface of the TFC membranes significantly more hydrophilic. The prepared membranes were then subjected to long term fouling studies using model foulants, including sodium humate (SH), silica particles (SPs), and chloroform (CF) spiked in the feed NaCl solution. The biofouling effect of silver salts was also studied by incorporating some silver salts (silver citrate hydrate, SCH; silver lactate, SL; and silver nitrate, SN) simultaneously with iLSMM into the TFC membranes. Halo test was conducted with Escherichia coli to examine the antibiofouling performance of the silver incorporated TFC membranes. It can be concluded by this work that iLSMM incorporated TFC membranes have performed excellently for the desalination of salty water (3.5 wt% NaCl), especially when the solution was spiked with typical foulants such as SH, SPs, and CF. The flux reduction was reduced significantly when iLSMM was incorporated in the TFC membranes by a newly developed technique. The antimicrobial fouling intensity of the studied membrane was in the order of: SN (ring width 0.55 mm) > SL (0.27 mm) > SCH (0.19 mm).

Disinfection byproducts (DBPs), trihalomethanes and haloacetic acids present in water are well known carcinogens and their removal is an important priority. Highly porous nanofibrous membrane filters produced by electro-spinning were carbonized and used for the removal of DBPs from water. In the present investigation, chloroform and monochloroacetic acid (MCAA) was used as model DBPs compounds. The DBPs concentration in the range of 1–100 mg/L was used in well controlled adsorption experiments using the prepared membranes. For chloroform an adsorption capacity of 554 mg/g of carbonized nanofibrous membranes (CNMs) was determined based on the filtration of feed solution (100 mg/L). The adsorption capacity of MCAA was between 287 and 504 mg/g for a feed concentration of 4–18 mg/L based on the static adsorption study. The used membranes were regenerated by chemical/physical treatment and removal efficiencies of the regenerated membranes were determined. The DBPs removal from water was also investigated using multiwalled carbon nanotubes (MWCNTs) incorporated in the CNMs and results were compared. Although the initial removal of MCAA was increased with increasing concentration of the MWCNTs, afterwards, the subsequent removals showed no effect of addition of MWCNTs. The possible mechanism was also discussed to better understand the adsorption phenomenon. These results suggest that the CNMs could be used as DBPs removal filter for drinking water purpose.

Removal of endocrine disrupting compound (viz., bisphenol A, BPA) by laboratory-fabricated hollow fiber polyethersulfone (PES) nanofiltration (NF) membranes have been investigated. The tailor made charged PES hollow fiber NF membranes have been developed by blending negatively charged surface modifying macromolecule (cSMM). It is resulted more than 90% removal of BPA, mainly due to negatively charged properties of the membrane and the negatively charged solute under the influence of higher pH feed water matrix. The PES hollow fiber modified by blending cSMM is associated with sulfonic groups, confirmed by energy dispersive X-ray and Fourier transform infrared analysis. The blending of cSMM has successfully modified PES hollow fiber which is resulted twice better removal of BPA compared to the unmodified PES.

The poly(ether sulfone) (PES) membranes were prepared by blending of two types of surface modifying macromolecules (SMMs)-charged (cSMM) and fluorinated (fSMM). Also, membranes were fabricated in three different conditions: (1) at room temperature (RT) without air-exposure period (the period between film casting and immersion into coagulation bath), (2) at RT with 3 min air-exposure period and (3) at 90 °C with 3 min air-exposure period. The performances and physico-chemical characteristics of the membranes were evaluated. Membrane surface became more hydrophilic when cSMM was blended while more hydrophobic when fSMM was blended. Detailed analysis of the surface free energy demonstrated that the hydrophilic surface was resulted form strong Lewis base (solid)–acid (liquid) interaction while hydrophobic surface was resulted from the weak Lifshitz–van der Waals interaction. Atomic force microscopy (AFM) results could be interpreted by considering the orientation of nodule aggregates at the membrane surface under the casting bar and its relaxation during the air-exposure period between the film casting and immersion to the gelation bath. The pore size of the membranes measured by AFM was much larger than the pore size obtained by filtration experiment.

The separation performances and physico-chemical characteristics of poly(ether sulfone) membranes were evaluated by blending of surface modifying macromolecules (SMMs). Hydrophobic SMMs (bSMM) and charged SMMs (cSMM) were synthesized and characterized. By addition of SMMs, glass transition temperature decreased and membrane pore size increased. The membrane became more hydrophobic by blending of bSMM, and became more hydrophilic after addition of cSMM. It was also demonstrated by the result of surface free energy study that the bSMM blended membrane showed the lowest solid–liquid (water) interaction by low Lifshitz–van der Waals interaction and Lewis acid (liquid)–base (solid) interaction. In contrast, cSMM blended membrane showed the highest Lewis acid–base interaction, which resulted in the highest interaction energy between membrane surface and liquid (water). It was also found from the result of differential scanning calorimeteric measurement that bound water was formed in the cSMM blended membrane.

Polyethersulfone (PES) hollow fiber membranes were fabricated using water and polyvinylpyrrolidone as additives and N-methyl pyrrolidinone as solvent. Asymmetric hollow fiber membranes were spun by the dry-wet phase inversion method. A charged surface modifying macromolecule (cSMM) was synthesized and blended into the PES dope. The modification of PES hollow fiber membranes with cSMM was evaluated via contact angle measurement, field emission scanning electron microscopy (FESEM), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR-ATR) and ionic solute separation performance. Experimental results showed that pure water permeation flux was increased by surface modification with the blended cSMM, which at the same time produced higher ionic solute rejection. From the FESEM, a small increase in the thickness of the hollow fiber outer layer was noticed when the surface was modified by cSMM blending. Nevertheless, there was no significant difference in the overall membrane morphology between the membranes with and without cSMM blending, indicating that the morphology of the base polymer remained practically unchanged. On the other hand, DSC scan and FTIR analysis confirmed the miscibility of cSMM with PES and the presence of cSMM's functional group, respectively.

Modification of sulfonated poly(ether ether ketone) (SPEEK) membrane was attempted by blending three newly developed charged surface modifying macromolecules (cSMMs) having three different polyols. Sulfur content of the cSMMs was analyzed by Fourier transform infra-red spectroscopy and elemental analysis to be in the following order: PEG200-HBS > PEG400-HBS > PPG-HBS, which was also the order for their glass transition temperature (Tg). The control and modified membranes were characterized by contact angle measurement, thermal analysis, X-ray photoelectron spectroscopy, atomic force microscopy and water uptake. The modified SPEEK membrane surfaces were more hydrophilic on the top surfaces than the bottom surfaces as indicated by the water contact angle and by XPS, confirming the stronger migration of cSMM to the top than the bottom surfaces. The cSMM has migrated and formed SO3 dense layer-like on top and bottom surfaces of the modified membrane. The morphology study of the membrane surfaces showed that the nodule size and surface roughness has also influenced the water uptake, apart from the additional SO3 group. The modified membranes were tested for methanol permeability and proton conductivity. Employing PEG200-HBS has resulted in the smallest nodule size, the lowest water uptake and the lowest methanol permeability. On the contrary, employing PPG425-HBS had the largest nodule size, the highest water uptake and the highest proton conductivity. The proton conductivity is more dependent on the capability of the membrane to sorb more water rather than the additional SO3 group introduced by the cSMM.

Two different types of hydrophobic surface modifying macromolecules (SMMs) were synthesized and characterized for fluorine content, average molecular weight and glass transition temperature. The synthesized SMMs were blended into polyetherimide (PEI) hydrophilic host polymer to form porous hydrophobic/hydrophilic composite membranes by the phase inversion method. The prepared membranes were characterized by the contact angle measurements, X-ray photoelectron spectroscopy test, gas permeation test, liquid entry pressure of water and scanning electron microscopy. Finally, these membranes were tested for desalination by direct contact membrane distillation (DCMD). Different parameters affecting the membrane preparation process were studied and their effects on the membrane morphology as well as on the membrane performance in clesalination by DCMD were identified. These parameters include the SMMs type, SMMs concentration, solvent type and solvent evaporation time before gelation. An attempt to link the membrane morphology to its performance in DCMD is presented. This leads to better understanding of the effect of the membrane preparation on its performance. it was found that increasing the solvent evaporation time before gelation decreased the membrane flux since smaller pore sizes were observed. The membranes with higher contact angles and fluorine contents (more hydrophobic) exhibited smaller permeate fluxes. The membranes having sponge-like structures at the hydrophilic layer exhibited higher fluxes than those having finger-like structure at the hydrophilic layer. Moreover, the results were compared to a commercial polytetrafluoroethylene (PTFE) membrane. It was observed that most of the SMMs blended PEI membranes achieved better DCMD fluxes than those of the commercial membrane. A permeate flux 55% higher than that of PTFE was achieved. For both PTFE commercial membrane and all SMMs blended PEI membranes, the NaCl separation factor was found to be higher than 99% except for the PEI membrane prepared without SMMs.

A new concept for the preparation of thin-film-composite (TFC) reverse osmosis (RO) membrane by interfacial polymerization on porous polysulfone (PS) support using novel additives is reported. Hydrophilic surface modifying macromolecules (LSMM) were synthesized both ex situ by conventional method (cLSMM), and in situ within the organic solvent of the TFC system (iLSMM). The effects of these LSMMs on the fouling of the TFC RO membranes used in the desalination processes were studied. FTIR results indicated that both cLSMM and iLSMM were present in the active layer of the TFC membranes. SEM micrographs depicted that heterogeneity of the surface increases for TFC membranes compared to the control PS membrane, and that higher concentrations of LSMM provided smoother surface. AFM characteristic data presented that the surface roughness of the skin surface increases for TFC membranes compared to the control. The RO performance results showed that the addition of the cLSMM significantly decreased the salt rejection of the membrane and slightly reduced the flux, while in the case of the iLSMM, salt rejection was improved but the flux declined at different rates for different iLSMM concentrations. The membrane prepared by the iLSMM exhibited less flux decay over an extended operational period.

Modification of sulfonated poly(ether ether ketone) (SPEEK) membrane was attempted by blending charged surface modifying macromolecule (cSMM). The modified membrane was tested for direct methanol fuel cell (DMFC) application; i.e. a SPEEK/cSMM blend membrane was compared to a SPEEK membrane and a Nafion 112 membrane for the thermal and mechanical stability, methanol permeability, and proton conductivity. Thermal and mechanical stability of the blended membrane were slightly reduced from the SPEEK membrane but still higher than the Nafion 112 membrane. The blend membrane was found to be promising for DMFC applications because of its lower methanol diffusivity (2.75 × 10 −7 cm 2 s −1 ) and higher proton conductivity (6.4 × 10 −3 S cm −1 ), than the SPEEK membrane. A plausible explanation was given for the favorable effect of cSMM blending.

This work focuses on utilizing the dual role of sulfonated polyphenyl sulfone (SPPSU) as both an anchoring agent and an interlayer modifying agent in the preparation of nano MgO/SPPSU/PPSU membranes for oil removal from water. These asymmetric membranes were prepared using the phase inversion technique. The dispersed nano MgO was observed in the membrane matrix as seen by scanning electron microscope and energy dispersive X-ray analysis. The reduction in contact angle value establishes the increases in hydrophilicity. An increase in SPPSU (wt %) loosens the nano MgO/SPPSU/PPSU membrane packing as exhibited by the increase of d-spacing by X-ray diffraction analysis. The antifouling properties were tested using humic acid, as a model foulant. Further, in castor oil/water emulsion separation, it was found that the membrane with 25 wt % anchored moiety SPPSU/nano MgO produced a greater flux recovery ratio of 94.9% (±0.3) without compromising the oil rejection of 99% (±0.4) and better oleophobic surfaces for oil. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 132, 42848.

Membrane distillation (MD) is a promising separation technique capable of being used in the desalination of marine and brackish water. Poly(vinylidene fluoride) (PVDF) flat sheet nano-composite membranes were surface modified by coating with electro-spun PVDF nano-fibres to increase the surface hydrophobicity. For this purpose, the nano-composite membrane containing 7 wt.% superhydrophobic SiO2 nano-particles, which showed the highest flux in our previous work, was first subjected to pore size augmentation by increasing the concentration of the pore forming agent (Di-ionized water). Then, the prepared flat sheet membranes were subjected to nanofibres coating by electro-spinning. The uncoated and coated composite fabricated membranes were characterized using contact angle, liquid entry pressure of water, and scanning electron microscopy. The membranes were further tested for 6 h desalination by direct contact membrane distillation (DCMD) and vacuum membrane distillation (VMD), with a 3.5 wt.% synthetic NaClaq as the feed. In DCMD the feed liquid and permeate side temperature were maintained at 27.5 °C and 15 °C, respectively. For VMD, the feed liquid temperature was 27 °C and a vacuum of 94.8 kPa was applied on the permeate side. The maximum permeate flux achieved was 3.2 kg/m(2).h for VMD and 6.5 kg/m(2).h for DCMD. The salt rejection obtained was higher than 99.98%. The coated membranes showed a more stable flux than the uncoated membranes indicating that the double layered membranes have great potential in solving the pore wetting problem in MD.

A facile one-pot approach for rapid synthesis of silver and gold nanoparticles (Ag NPs and Au NPs) with narrow size distribution and good stability was described by reducing silver nitrate and chloroauric acid with polysaccharide dextrin. Here, dextrin was used as both a reducing and stabilizing agent for synthesis of NPs. The as-synthesized Ag NPs and Au NPs were characterized by UV–visible absorption spectroscopy, transmission electron microscopy (TEM) and X-ray diffraction (XRD). The Ag NPs and Au NPs exhibited an absorption maxima at 404 and 547 nm respectively. TEM images showed NPs in the range of 8–28 nm. The crystallinity of the NPs was measured by XRD analysis. Furthermore, the as-prepared Ag NPs revealed colorimetric sensor property for detection of Cu2+ ions based on changes in absorbance resulting from metal ion-induced aggregation of NPs or direct deposition of metal ions onto NPs. The as-prepared Au NPs exhibited a notable catalytic activity toward the reduction of 4-nitrophenol to 4-aminophenol in the presence of NaBH4.

The Handbook of Membrane Separations: Chemical, Pharmaceutical, Food, and Biotechnological Applications, Second Edition provides detailed information on membrane separation technologies from an international team of experts. The handbook fills an important gap in the current literature by providing a comprehensive discussion of membrane application

A new type of hydrophilic surface modifying macromolecules (LSMMs) were synthesized by end-capping urethane prepolymer with poly(ethylene glycol)s, PEGs, of average molecular weights 400, 600, and 1000 Da and poly(propylene glycol) of a average molecular weight 425 Da. They were characterized and blended into the casting solutions of poly(ether sulfone), PES, to prepare ultra-filtration (UF) membranes by the phase inversion technique. The membranes, both pure PES and LSMM blended PES, were then characterized by contact angle (CA) measurements and UF studies using PEG and poly(ethylene oxide), PEO, solutes of different molecular weights. LSMM blended PES membranes were more hydrophilic than the PES membranes based on CA data. The molecular weight cut-off (MWCO), mean pore size (μp) with geometric standard deviation, pore size distribution, pore density, and surface porosity of the membranes were determined by using UF solutes (PEG and PEO) transport data. LSMMs created lower MWCO, lower μp, and also narrower pore size distributions of the PES UF membranes. The significant effect of LSMM blending is discussed.

Hydroxyl-terminated polybutadiene (HTPB) was blended into a poly(ether sulfone) (PES) casting solution used to prepare ultra-filtration (UF) membranes via the phase inversion technique. The membranes were then characterized by contact angle (CA) measurements and UF experiments. The CA was increased with the addition of HTPB in the PES membrane and also by lowering the gelation bath temperature. It was observed that the CA was lower for membranes prepared with N-methyl-2-pyrrolidinone (NMP) as the solvent than those using N,N-dimethylacetamide (DMAc) as solvent. The flux values were higher for membranes made using a 4°C gelation bath when compared with the ambient temperature ((25 ± 1)°C) irrespective of the cast solvents, NMP or DMAc. The flux values were much higher and the solute separations were lower for the HTPB-based PES membranes than for the pure PES membrane, when the membranes were cast with DMAc as a solvent. On the other hand, both flux and separation values were much lower for the HTPB-based PES membranes than for the pure PES membrane, when the membranes were cast using NMP. Atomic force microscopy and scanning electron microscopy were used for morphological characterization and the correlation of topography/photography with the performance data was also examined. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2292–2303, 2006

Dense cellulose acetate, CA, and poly(2,6-dimethyl-1,4-phenylene oxide), PPO, membranes were prepared with and without blending a spin probe, TEMPO free radical, and their 13C solid-state cross-polarization magic angle spinning nuclear magnetic resonance, CPMAS NMR, spectra were taken. It was observed that there was no effect of blending TEMPO on the CPMAS NMR spectra of CA and PPO membranes. It was concluded that there was no chemical or physical interaction between the polymeric material and TEMPO. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3062–3069, 2006

A hydrophiLic Surface Modifying Macromolecule (LSMM) was synthesized, characterized, and blended into the casting solution of polyethersulfone (PES) membranes. Ultra-filtration membranes were prepared by the phase inversion technique. The membranes were then characterized by contact angle measurements and a solute transport study using poly(ethylene glycol) (PEG) and poly(ethylene oxide) (PEO) solutes of different molecular weights. Pore size and pore size distribution of the membranes were determined by using PEG and PEO separation data. The Ottawa River water was treated by the membranes. The LSMM blended PES membranes showed higher fouling resistance and long-term stability than the PES membrane without LSMM.

The physicochemical properties of mixed polymeric surfactant systems were studied with different techniques. A binary system consisting of lignosulfonate and petroleum sulfonate and a ternary system consisting of two different lignosulfonates and petroleum sulfonate were studied with respect to phase behavior, interfacial tension, specific conductivity, and pH measurements. In addition, the original lignosulfonates were subjected to ion exchange from sodium to calcium or vice versa, and the effects were investigated. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 860–865, 2003

Polyacrylonitrile (PAN)/acrylamide (AM) precursor fibers prepared using a solvent-free coagulation process were stabilized, carbonized, and physically activated by carbon dioxide (CO2) into activated carbon fibers (ACFs). The activation temperature varied from 800 to 900 °C while the activation time was 60 minutes. Scanning electron microscopy (SEM) micrographs show that the porosity increased after the activation process, resulting from the loss of volatile components. The specific surface area increased markedly after the activation process; it was several hundred times greater than before the process. It was concluded that there is a big potential for PAN/AM-based ACFs prepared using solvent-free coagulation bath as an adsorbent of natural gas.

In the present study, the self-synthesized thin film nanocomposite (TFN) membrane incorporated with hydrophilic functionalized titanate nanotubes (TNTs) has been fabricated and tested for forward osmosis (FO) desalination. The ATR-FTIR results showed that NH 2 -TNT S were successfully modified by AATPS and while TEM and XRD revealed the tubular morphology and crystal structure of NH 2 -TNTs nanotubes, respectively. The presence of the chemical bondings between NH 2 -TNTs and polyamide (PA) selective top layer of TFN is corroborated with the FTIR results. The existence of NH 2 -TNTs in PA top layer was further confirmed by XPS analysis on the control and TFN membranes. The effect of NH 2 -TNTs on the PA layer was investigated and discussed in terms of surface morphology and separation performance. The morphology of the PA layer was investigated through FESEM and AFM micrographs and the outgrowth of the “leaf-like” structure was observed following the increase in NH 2 -TNTs content. Compared to the thin film composite (TFC) control membrane, the TFN membrane embedded with 0.05 wt% NH 2 -TNTs (designated as TFN0.05) exhibited two times improvement in water flux without sacrificing salt rejection.

The association between lignosulfonate (LS) and an anionic surfactant, sodium dodecyl sulfate (SDS) has been investigated by surface tension measurement. Three different LS samples were used in this study. In every case, the critical micelle concentration (CMC) value was close to about 4 mmol/l for mixed systems whereas the CMC value for SDS alone is about 8 mmol/l. Surface tension measurements at different concentrations of LS indicated that LS alone behaves as a polymeric surfactant. In the mixed LS/SDS surfactant system however, it appears that LS behaves primarily as a polyelectrolyte.

Polymeric nanocomposites embedded with nontoxic antimicrobial agents have recently gained potential industrial significance, mainly for their applicability to preserve food quality and ensure safety. In this study, a poly(butylene adipate-co-terephthalate) (PBAT)/organoclay (CMMT) based nanocomposite film doped with sodium benzoate (SB) as antimicrobial agent was prepared by a solution mixing process. A homogenous dispersion of organoclay (cetyltrimethylammonium-modified montmorillonite [CMMT]) in PBAT matrix was observed by X-ray diffraction and transmission electron microscopy. PBAT/CMMT nanocomposite film showed higher barrier properties against water and methanol vapor compared to the PBAT film. The release of SB from PBAT and its nanocomposite film was measured and the relevant data were fitted to the Weibull model. The higher values of Weibull's shape factor and scale parameter as corroborated by experimental findings indicated faster rate of SB release from PBAT/CMMT/SB nanocomposite film, when compared to the pristine PBAT film. Bacterial inhibition studies were accomplished against 2 food pathogenic bacteria, Bacillus subtilis and Staphylococcus aureus, by determining the zone of inhibition and corresponding growth profiles. Both bacterial inhibition studies and growth profiles established that PBAT/CMMT/SB demonstrated better antimicrobial activity than PBAT/SB film. Therefore, PBAT/CMMT/SB nanocomposite film can be used for food packaging application as it showed good barrier properties and antimicrobial activity against food pathogenic bacteria.

The effect of weight average molecular weight (Mw) of methyl cellulose (MC) on the gelation behavior of Poloxamer 407 (PM) and in vitro release of Ketorolac Tromethamine (KT) from different ophthalmic formulations based on PM is examined. A drop of gelation temperature of PM is observed using MC of various M(w) by test tube tilting method, UV-vis spectroscopy, viscometry and rheometry. It is also observed that the viscosity and gel strength of all the formulations are increased with the increase in Mw of MC. PM with highest Mw of MC provides best drug release property among all the formulations. It is evident from this investigation that there is a distinct effect of M(w) of MC on the gelation behavior of PM as well as on the drug release profile of KT from PM-MC based ophthalmic formulations.

The innovative design and synthesis of nanofiber based hydro-philic/phobic membranes with a thin hydro-phobic nanofiber layer on the top and a thin hydrophilic nanofiber layer on the bottom of the conventional casted micro-porous layer which opens up a solution for membrane pore wetting and improves the pure water flux in membrane distillation.

The effects of a ready-made surfactant (sodium dodecyl sulfate) on the dynamic interfacial tension between a model acidic oil (linoleic acid dissolved in paraffin oil) and various aqueous alkaline (NaOH) systems have been studied using pendant drop tensiometry at surfactant concentrations both below and above the critical micelle concentration (CMC). Below the CMC the added surfactant contributes significantly to a further reduction of interfacial tension of the reacting acid/alkaline system, whereas above the CMC the added surfactant plays an important role in damping the dynamic trends observed for the reactive system alone. Copyright 2001 Academic Press.

Interactions between a polymer and a surfactant were studied via surface tension measurements. Poly(ethylene glycol) and sodium dodecyl sulfate were used as a polymer and a surfactant, respectively. The addition of polymer affected the CMC value of the surfactant. The interpretations of the data and theoretical plots of polymer-surfactant interactions are discussed using a theoretical model.

The rheology and morphology of four sets of binary blends of polyethylene synthesized with metallocene catalysis (metallocene polyethylene: MCPE) with polyolefins prepared using Ziegler-Natta catalysts have been investigated. The blend systems are MCPE with high density polyethylene (MCPE-HDPE), polypropylene (MCPE-PP), poly(propylene-co-ethylene) (MCPE-CoPP), and poly(propylene-co-ethylene-co-1-butylene) (MCPE-TerPP). Cole-Cole plots [storage melt viscosity (η′) versus loss melt viscosity (η″)], plots of the dynamic storage modulus (G′) versus the dynamic loss modulus (G″), and plots of the log melt viscosity (η*, η′, and η″) versus blend compositions were constructed. The morphology of the blends after microtoming and etching was studied. The phase morphology of MCPE-HDPE appeared homogeneous, whereas the other three blends were heterogeneous. Rheological and morphological investigations indicated that the MCPE-HDPE blend was miscible, but the other three blends were immiscible in the melt as well as in the solid state. These observations can be rationalized in terms of the similarity of the chemical structures of the polyolefins.

The rheological and morphological behaviors of commercially available three binary blends of ethylene 1-octene copolymer (EOC) regarding the melt index (MI), density and comonomer contents, one component made by the Ziegler–Natta and the other by the metallocene catalysts, were investigated to elucidate miscibility and phase behavior. Miscibility of the EOCs blend in a melt state was related to the value of the MI, density, and comonomer content. If the comonomer contents are similar, then the melt viscosity is weight average value, otherwise it is positively or negatively deviated. The microtomed surface prepared by two different cooling processes—one is fast cooling and the other is slow cooling—indicated that all the blends were not homogenous regardless the density, MI, and comonomer content. The Ziegler–Natta catalyzed EOCs exhibited bigger spherulitic diameter and larger ring space than those of the metallocene EOCs prepared by a cooling process. The blends consisting of similar MI showed banded spherulites with different diameter, whereas the blend consisting of different MI and density takes place of explicit phase separation and phase inversion at 1 : 1 blend composition. The melt rheology appeared to influence the mechanical and film properties in the solid state. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1950–1964, 2000

The thermal, viscoelastic, and mechanical behaviors of three binary blends of ethylene 1-octene copolymer (EOC) regarding the melt index and density, one component made by Ziegler–Natta (FA and RF in abbreviation of the commercial name) and the other by metallocene catalysts (FM, EN and PL in abbreviation of the commercial name), have been investigated to understand molecular mechanism of the blends. Thermal studies reveal that the two constituents in the three blends exclude one another during crystallization, implying a phase separation. Viscoelastic properties show a single β or γ transition in all the compositions, suggesting a miscibility in the amorphous region. The tensile modulus, yield stress, maximum strength at break, and elongation at break follow the rule of mixtures if the comonomer content does not differ too much. Otherwise, the modulus and yield stress are negatively deviated, whereas elongation at break is positively deviated from the weight-average value. The tensile properties of film at yield and break in the machine direction is increased with an addition of FM in the FA + FM blend. Although all three blends form separate crystals in the crystalline state, a correlation exists between the mechanical properties and the density of EOCs. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1169–1177, 1999

Migration diffusion coefficients of two surfactants (sorbitan laurate, SPAN-20 and sorbitan palmitate, SPAN-40) in polyethylene blend are calculated in the desorption process by means of Fourier transform infrared (FT-IR) spectroscopy technique at 25°C. They are 2.31 and 2.24 × 10−11 cm2/s, respectively, which show no significant dependency of molecular weights of the surfactants on diffusion. The composition of LLDPE (linear low-density polyethylene) and LDPE (low-density polyethylene) in LLDPE blend is a 7 : 3 ratio, and ethylene acrylic acid (EAA) copolymer is used to verify its role as a migration controller. The key factor affecting the diffusion of the surfactant is suggested to be the segmental mobility by the semicrystalline LLDPE blend. Incorporation of 20 wt% EAA in the LLDPE blend retards the migration rate of the surfactants by reducing the diffusion coefficients to be 9.6 and 7.7 × 10−12 cm2/s and this is believed to be due to the blocking effect of EAA. Although the diffusion coefficient was varied from system to system, the migration kinetics of the surfactants in short times obeys the Fickian behavior if the experimental error is allowed. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 1387–1395, 1999

The thermal and mechanical properties for four binary blends, high-density polyethylene (HDPE)–metallocene polyethylene (MCPE), polypropylene (PP)–MCPE, poly(propylene-co-ethylene) (CoPP)–MCPE, and poly(propylene-co-ethylene-co-1-butene) (TerPP)–MCPE were investigated to compare the compatibility and molecular micromechanism of the blends. We report in this work all the blend systems that are thermodynamically immiscible but mechanically compatible which have been understood by their thermal and mechanical behaviors. A lower content of MCPE (up to 50%) in PP–MCPE, CoPP–MCPE, and TerPP–MCPE blends showed discernibly two β transitions, whereas β relaxation was shifted to a lower temperature with the MCPE content in the HDPE–MCPE system. These results conclude that the degree of compatibility in the HDPE–MCPE blend is the largest among the blend systems that we have studied, which also can be explained in terms of the similar chemical structure of polyolefins. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 2441–2450, 1998

The aim of this work is to examine the effectiveness of mucilage/hydroxypropylmethylcellulose (HPMC) based transdermal patch (matrix type) as a drug delivery device. We have successfully extracted mucilage from Colocasia esculenta (Taro) corms and prepared diltiazem hydrochloride incorporated mucilage/HPMC based transdermal patches using various wt% of mucilage by the solvent evaporation technique. Characterization of both mucilage and transdermal patches has been done by several techniques such as Molisch's test, organoleptic evaluation of mucilage, mechanical, morphological and thermal analysis of transdermal patches. Skin irritation test is studied on hairless Albino rat skin showing that transdermal patches are apparently free of potentially hazardous skin irritation. Fourier transform infrared analysis shows that there is no interaction between drug, mucilage and HPMC while scanning electron microscopy shows the surface morphology of transdermal patches. In vitro drug release time of mucilage-HPMC based transdermal patches is prolonged with increasing mucilage concentration in the formulation.

In this chapter, we review the elastomeric composites with different types of one dimensional nanofillers e.g. nanotubes, nanorods and nanofibers. Various elastomers and nanofillers have been considered along with the preparation methods of the composites. The dispersion level and surface morphologies have been reported having various fillers and how do they vary with the chemical modifications on the filler along with the effect of dispersing agent. The improvement in thermal and mechanical properties including dynamic mechanical properties of elastomers has been discussed in presence of one-dimensional nanofillers. Viscoelasticity has been reviewed for elastomeric systems and, especially, how the non-linearity appears in presence of one-dimensional filler. Rheological properties including curing kinetics, storage and loss modulus, and complex viscosities as a function of frequency of the nanocomposites have been discussed in detail. Dynamic mechanical studies related to various elastomer nanocomposites with various one dimensional fillers have been reported with possible explanations. The influence of the nature of fillers with their chemical modifications of one-dimensional filler on the viscoelasticity has also been assessed.

Poly(butylene adipate-co-terephthalate) (PBAT) nanocomposites films are prepared by a solution intercalation process using natural montmorillonite (MMT) and cetyltrimethylammonium bromide (CTAB)-modified montmorillonite (CMMT). Cation exchange technique has been used for modification of MMT by CTAB and characterized by Fourier transform infrared analysis, thermo-gravimetric analysis, and X-ray diffraction (XRD) studies. CMMT gives better dispersion in the PBAT matrix than MMT and is confirmed by XRD and transmission electron microscopy. Because of better compatibility of CMMT, water vapor transmission rate of PBAT decreases more in the presence of CMMT than MMT. The biodegradability of PBAT and its nanocomposite films are studied in compost and from the morphological analysis it is apparent that the PBAT/CMMT shows a lower biodegradation rate in comparison to the PBAT/MMT. The antimicrobial activity of PBAT and its nanocomposite films is tested by an inhibition zone method. Because of the presence of the quaternary ammonium group of CTAB-modified MMT, PBAT/CMMT nanocomposites show adequate antimicrobial activity. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40079.