Abstract  Description of tables of property constants description of tables of equation coefficients synonyms list key for equation forms general references list of compound names.

Abstract  This study sought to develop an injectable formulation for long-term ocular delivery of fluocinolone acetonide (FA) by dissolving the anti-inflammatory drug and the biodegradable polymer poly(propylene fumarate) (PPF) in the biocompatible, water-miscible, organic solvent N-methyl-2-pyrrolidone (NMP). Upon injection of the solution into an aqueous environment, a FA-loaded PPF matrix is precipitated in situ through the diffusion/extraction of NMP into surrounding aqueous fluids. Fabrication of the matrices and in vitro release studies were performed in phosphate buffered saline at 37 degrees C. Drug loadings up to 5% were achieved. High performance liquid chromatography was employed to determine the released amount of FA. The effects of drug loading, PPF content of the injectable formulation, and additional photo-crosslinking of the matrix surface were investigated. Overall, FA release was sustained in vitro over up to 400 days. After an initial burst release of 22 to 68% of initial FA loading, controlled drug release driven by diffusion and bulk erosion was observed. Drug release rates in a therapeutic range were demonstrated. Release kinetics were found to be dependent on drug loading, formulation PPF content, and extent of surface crosslinking. The results suggest that injectable, in situ formed PPF matrices are promising candidates for the formulation of long-term, controlled delivery devices for intraocular drug delivery.

Abstract  UNLABELLED: Here, we fabricated a highly conductive poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (

PEDOT: PSS) nanofilm via vacuum filtration with enhanced thermoelectric power factor by doping of liquid exfoliated graphene (GE) and hydrazine treatment. The effect of GE exfoliated in dimethylformamide (DMF) and N-methyl-2-pyrrolidone (NMP) on the electrical conductivity and thermopower of

PEDOT: PSS was investigated. Although electrical conductivity decreased with increasing GE, thermoelectric power factors of

PEDOT: PSS nanofilms were improved with 3 wt % GE in DMF (38.6 μW m(-1) K(-2)) and in NMP (28.0 μW m(-1) K(-2)) compared to pure

PEDOT: PSS (11.5 μW m(-1) K(-2)). The mechanism of improvement was proposed to be the removal of PSS and the good interaction between PEDOT and GE. With hydrazine treatment, 3 wt % GE-doped

PEDOT: PSS nanofilm (PG3) showed a further enhanced power factor of 53.3 μW m(-1) K(-2) (∼5 times higher than that of pristine

PEDOT: PSS nanofilm). The effects of hydrazine containing concentration, treatment time, and temperature on the electrical conductivity and Seebeck coefficient of PG3 were investigated systematically. An estimated thermoelectric figure of merit (ZT) is 0.05 with the optimized power factor at room temperature.

Abstract  At room temperature, silver nano-sized particles were one-step prepared by a novel facile method of the reduction of silver nitrate with o-Phenylenediamine (o-PD) in a mixed solution of water and N-Methyl-2-pyrrolidone(NMPD). Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were employed to characterize as-prepared silver nanoparticles. The SEM images show that silver nano-particles are well spherical and possessed of uniform particle size, and the average particle size is about 70 nm. The XRD pattern indicates that the values of d(hkl), a, and unit cell volume (V-3) of Ag crystal are all a little greater than that of Ag standard card, with face-centred cubic structure. UV-visible spectra (UV-Vs) and liquid chromatography-mass spectrometry (LC-MS) was used to identify the product of oxidation of o-PD in solution after reaction. The results of UV-Vs and LC-MS illustrate that the product of oxidation of o-PD in solution is 2,3-diaminophenazine.

Abstract  An anode magnetron enhanced d.c. cathodic plasma treatment of a cold-rolled steel (CRS) plate and cathodic (plasma) polymerization were used to create interface engineered systems of cathodic E-coat/plasma polymer/plasma treated CRS. The adhesion of the E-coat and the corrosion protection characteristics of the systems were compared with the control, E-coat/Zn phosphate-chromate/electro-galvanized steel (EGS). The adhesion of the E-coat to the plasma polymer coated CRS was found to be excellent; the E-coat could not be removed by N-methyl pyrrolidone (60 degrees C) in 5 days, while the same E-coat applied on the control was removed in a few minutes. The plasma polymer of trimethylsilane (TMS) was found to yield excellent corrosion protection as used in the interface engineered systems, of which the corrosion (GM scab) test was found to be better than that for the control. The plasma pretreatment of the CRS surface prior to the cathodic polymerization of TMS was found to be a critically important factor. The corrosion-induced delamination of the first paint layer seems to play a key role in the corrosion of painted steel. Tt was demonstrated that good adhesion and durability of the entire interface system can produce a highly corrosion resistant painted CRS.

Abstract  Pt skin growth over PdPt alloy nanocrystals has been described using a simple wet chemical method, where a layer-by-layer epitaxial deposition of Pt on PdPt could be understood by the Stranski-Krastanov mechanism. Initial PdPt alloy nanocrystals grown in a simple wet-chemical method, in the presence of a reducing solvent like N-methyl pyrrolidone (NMP) and a stabilizer like polyvinyl pyrrolidone (PVP), have been used as the substrate for secondary growth of a Pt thin layer. Surface changes have been observed during step-by-step growth of polyhedral Pt skin@PdPt nanocrystals originating from nearly octahedral geometries of PdPt. The methanol electrooxidation activities of two different Pt skin@PdPt nanostructures have been compared with PdPt nanocrystals with similar compositions but without skin structures and commercial RuPt catalysts. A gain factor of 8 towards electrooxidation of methanol in acidic media with activities of 1950 mA mg(Pt)(-1) and 3.1 mA cm(Pt)(-2) (with lower onset potential compared to the RuPt commercial catalyst), which is believed to be much higher compared to that of previous reports and state-of-art RuPt/C catalysts, indicating better surface properties and core-alloy formation along with improved intraparticle active interfacial sites. Additionally, exciting results of electrooxidation of ethanol and ethylene glycol with 70% and 58% activity retention respectively, after 5000 cycles are also found, demonstrating a facile C-C breaking in such C2 type alcohols.

Abstract  New polyethers with pendant chloromethyl groups were successfully synthesized by a polyaddition of bisepoxides with 4,4'-dichloro-3,3'-dinitrodiphenyl sulfone (DCNS) using quaternary onium salts or crown ether complexes as catalysts. The polyaddition of DCNS with diglycidyl ether of bisphenol A (DGEBA) was enhanced efficiently by the addition of tetrabutylammonium chloride (TBAC), tetrabutylammonium bromide (TBAB), or tetrabutylphosphonium chloride (TBPC) as catalysts. It was also found that the reaction proceeded smoothly in amide-type polar solvents such as N,N-dimethylacetamide (DMAc) and N-methyl-2-pyrrolidone (NMP) to give a high molecular weight polyether P-1. The polyaddition of DCNS with diglycidyl ether of ethylene glycol (DGEEG) using TBAB in DMAc also proceeded to give the polyether P-2 in good yield. The resulting polyethers contain reactive chloromethyl groups in a side chain, which was introduced during main chain formation.

Abstract  Nylon-6/epoxy resin composite with multiphase morphology has been successfully prepared via polymerization of caprolactam in N-methylpyrrolidone using N-acetyl caprolactam as the initiator. This was followed by reactive blending of appropriate amount of the plastic with epoxy resin. The structure of nylon-6 prepared by solution polymerization is predominantly [200, 020] crystalline form with [002] crystalline form as the minor phase. Subsequently, nylon-6/epoxy composite was prepared at 150 degrees C in a Teflon mold. A remarkable heterogeneous morphology of the fractured surface of the film was observed, consisting of multilayered fiber-like crystals encapsulated in the epoxy resin matrix. Close inspection of the morphology of the composite revealed a preference of nylon-6 to crystallize in the crevices and cracks created in glassy epoxy matrix during processing. The crystals seem to nucleate spontaneously and grow radially into spherulites. POLYM. ENG. SCI., 54:858-866, 2014. (c) 2013 Society of Plastics Engineers

Abstract  The copolymers of N-vinyl-2-pyrrolidone (N-VP) and condensation cardo and/or fluorinated condensation polymers (aromatic polyamide, polyimide and polyarylate) were-synthesized by free radical in situ polymerization. The partial formation (14-61 wt%) of polivnylpyrrolidone (PVP) homopolymer upon the polymerization of N-VP containing dissolved condensation polymer was stated. Synthesized (co)polymers are differed in heat resistance and solubility from neat PVP. Using relevant copolymers solutions in N-methyl-2-pyrrolidone the optical fiber coatings having good adhesion properties were fabricated. Such coatings demonstrate high stability at elevated temperatures. A substantial number of defects on coatings and a slight decrease in bending strength are observed only on exposure at 200 degrees C for 72 h. Simultaneously holding for 1 and 24h at the same temperature leads to hardening of the fibers: bending strength changes from similar to 5 up to 6 GPa. (C) 2016 Elsevier B.V. All rights reserved.

Abstract  A new polythiophene derivative has been synthesized by both chemical and electrochemical oxidative polymerization of the monomer 3,4-ethylenedithiathiophene (EDTT). Both methods produce a polymer which is completely soluble in 1-methyl-2-pyrrolidinone (NMP) and partly soluble In tetrahydrofuran (THF) and chloroform. The FT-IR spectra of the neutral polymer indicate a regular structure formed via alpha,alpha coupling of thiophene rings. The new polymer shows two absorption bands at 341 nm and 413-419 nn in NMP solution in the UV-vis region. Photoexcitation of the polymer in dilute NMP solution results in a broad band luminescence with peak at ca. 552 nm. The redox behavior of the polymer was studied by cyclic voltammetry in 0.1 M (Bu(4)N)ClO4 acetonitrile solution. The average molecular weights have been determined by gel permeation chromatography (GPC) to be M(n) similar to 3.03 x 10(3) and M(n) similar to 4.75 x 10(3) for the chemically and electrochemically synthesized polymer, respectively. Electron spin resonance data are reported. Thermal gravimetric analysis studies show that the new polymer is stable in nitrogen up to 276 degrees C. The chemically doped (with FeCl4-) polymer and the electrochemically doped (with ClO4-) polymer show electrical conductivity of 0.1 and 0.4 S/cm at room temperature, respectively. These results are compared to some previously characterized polythiophenes.

Abstract  Poly (L-lactic acid) (PLLA) membranes were fabricated through immersion precipitation method. 1, 4-dioxane (DX), N-methyl-2-pyrrolidone (NMP), N, N-dimethylformamide (DMF), N, N-dimethyl-acetamide (DMAc), and DX/NMP, DX/DMF and DX/DMAc were used as solvents severally. With a focus on the PLLA/DX/NMP/H2O system, the effect of solvent mixture on PLLA membrane was investigated by altering the ratio of DX/NMP. Various membrane morphologies were obtained, which were further correlated by mean of solubility parameter and viscosity of casting solution. It was found that the membrane cast with DX/NMP (1/1) exhibited ideal structure and better performance compared with membranes cast with same concentration of PLLA.

Abstract  Single-walled carbon nanotubes (SWNTs) were dispersed in N-methyl-2-pyrrolidone (NMP), N,N-dimethylformamide (DMF), and NN-dimethylacetamide (DMA), respectively. The nonlinear optical properties of SWNT dispersions were studied using the open aperture Z-scan technique at 532 nm. The nonlinear extinction coefficients strongly increase with increasing SWNT concentration. In the three dispersions, the DMF dispersions show the strongest nonlinear extinction effect. In conjunction with this, the optical limiting performance is also superior for the DMF dispersions. Compared with DMF and DMA, NMP has a much better debundling effect for SWNTs; however, the optical limiting properties of the NMP dispersions is inferior. The SWNT dispersions seem to attenuate the intense light more effectively, as is shown by the stronger optical limiting response compared to the zinc plithalocyanine solution, at the same concentration. The static light scattering experiment revealed that the DMF dispersions have the largest average bundle size. The main origin of the optical limiting effect of the SWNT dispersions is due to the solvent and/or carbon vapor bubble-induced nonlinear scattering. Our results show that the average bundle size of SWNTs in combination with the physical properties of the solvent dominate the nonlinear extinction and optical limiting properties of SWNT dispersions.

Abstract  Nonlinear optical and optical limiting properties of a range of single-walled carbon nanotube dispersions prepared in N-methyl-2-pyrrolidinone (NMP) were studied using the open aperture Z-scan technique at 532 nm. As the appropriate thermodynamic properties of the solvents are much more important than the bundle size of nanotubes for improving the optical limiting performance, the solvent parameters were controlled by either changing the temperature of the dispersions or blending a secondary solvent. While the optical limiting performance can be varied freely by increasing or decreasing the temperature from room temperature to 100 degrees C, the reduction of temperature below the freezing point of NMP and then down as far as -80 degrees C has little influence on the limiting. performance. As a result of adding a small amount of organic solvent into the NMP dispersions, the nonlinear optical responses were enhanced significantly clue to the reduction of surface tension and other parameters. By contrast, the addition of water leads to a decrease in the optical limiting response. Nanotube dispersions in water/surfactant exhibit a similar limiting performance to the nanotubes in NMP. Our results reveal that the optical limiting performance of the nanotube dispersions can be engineered by adjusting the solvent properties. Because the carbon nanotube dispersions are typical of the thermally induced light scattering dominated optical limiting materials, we believe the conclusions tit not only the nanotubes but also other nanomaterials with the similar limiting mechanism.

Abstract  The effects of dope flow rate and flow angle within a spinneret during spinning hollow fiber membranes on the morphology, water permeability and separation performance of poly(ethersulfone) ultrafiltration hollow fiber membranes were investigated. For this purpose, two spinnerets with different flow angles were designed and used. The dope solution, containing polyethersulphone (PES)/N-methyl-2-pyrrolidone (NMP)/diethylene glycol (DG) with a weight ratio of 23/41/36, which was very close to its cloud point (binodal line), was used in order to speed up the coagulation of nascent fibers so that the relaxation effect on molecular orientation was reduced. The wet-spinning process was purposely chosen to fabricate the hollow fibers without extra drawing. Therefore, the effects of gravity and elongation stress on fiber formation could be significantly reduced and the orientation induced by shear stress within the spinneret could be frozen into the wet-spun fibers. Experimental results suggest that higher dope flow rates (shear rates) in the spinneret produce UF hollow fiber membranes with smaller pore sizes and denser skin layers due to the enhanced molecular orientation. Hence, the pore size and the water permeability decrease, but the solute separation increases. Hollow fibers spun from a conical spinneret have smaller mean pore sizes with larger geometric standard deviations, thus exhibiting lower water flux and greater solute separation than hollow fibers spun from a traditional straight spinneret. In addition. SEM studies indicate macrovoids response differently for the 90degrees straight and 60degrees conical spinnerets when increasing the dope flow rate. Macrovoids can be significantly suppressed and almost disappear in the 90degrees spinneret at high dope flow rates. This phenomenon cannot be observed for the 60degrees conic spinneret. (C) 2004 Elsevier B.V. All rights reserved.

Abstract  This paper demonstrates a methodology for preparing patterned graphene films through the destabilization of dispersed graphene in N-methyl-pyrrolidone (NMP) by addition of water, which causes the graphene to be trapped at the interface of NMP/hexane. The trapped graphene film is transferred onto the patterned wetting/nonwetting surface through dip-coating process. The quality of graphene film is studied by scanning electron microscopy and atomic force microscopy. The sheet resistance of graphene film is 1.49 x 10(2) k Omega/square with surface coverage of 70% measured by the four-probe method. Field effect transistor based on such patterned graphene film is then fabricated. The current on/off ratio of devices is 1.24 with field-effect hole mobility of 159 cm(2)/Vs.

Abstract  La0.6Sr0.4Co0.2Fe0.8O3-alpha (LSCF) perovskite powders having a submicrometer size were synthesized by a sol-gel autocombustion method. From these powders, the gastight LSCF hollow-fiber membranes with a highly asymmetric structure comprising a dense layer of thickness ca. 88 mu m integrated with a porous substrate were fabricated in a single step through a phase inversion/sintering technique with a mixture of N-methyl-2-pyrrolidone (NMP) and water as internal coagulant. Oxygen permeation fluxes through the obtained hollow-fiber membranes were measured under air/He gradients at different temperatures. The results indicate that the highly asymmetric hollow-fiber membranes possess an oxygen permeation flux of 0.11-2.19 mL cm(-2) min(-1) in the temperature range of 650-1000 degrees C, which is 2.6-10.5 times higher than that of the sandwich-structured hollow-fiber membranes. Oxygen permeation in the hollow-fiber membranes is limited primarily by the surface exchange reactions at lower temperatures, but ionic bulk diffusion will have a rate-limiting effect at temperatures higher than 900 degrees C.

Abstract  To investigate the benefits of pretreatment in pyrolysis of heavy fractions, a feedstock in the range of gas oil has undergone aromatic extraction at different temperatures and solvent/oil ratios with n-methyl-2-pyrrolidone as the solvent. The raffinate with least aromatic content in addition to the original feed were subjected to steam cracking at different operating conditions to compare their product distributions with respect to the individual effects of temperature, flow rate, and dilution ratio. The experimental design was carried out with the use of the central composite design methodology. We find that the yields of ethylene, propylene, and butylenes increase by more than 10% upon dearomatization. The liquid products with five or more carbon atoms decrease by 13% on average. From desirable products, only butadiene reduced by about 18% upon extraction. Furthermore, a practical selectivity factor was proposed to support the preference of low residence time cracking and more generally to scrutinize the performance of the steam cracking process. Simulation results suggested a 2-fold increase in furnace run length in possible application of this treatment in a real olefin plant.

Abstract  Generating power from HyperCoal is a high- efficiency process in which the organic portion of coal is extracted with industrial solvents at a temperature around 360 degrees C and fed to a gas turbine directly. This study sought to establish a selection index for identifying subbituminous coals that give high extraction yields. Subbituminous coals were extracted at 360 degrees C with flowing industrial solvents, and we investigated the relationship between the extraction yield and the quantity of oxygen-containing functional groups in the coal. The extraction yield with a polar solvent, crude methylnaphthalene oil ( CMNO), increased with the quantity of carboxylate groups bridged by metal cations, such as Ca2+ and Mg2+ (COOM). The correlation coefficient between the extraction yield and the quantity was 0.82. Acid treatment of coal before extraction released COOM cross-links, increasing the extraction yield. These results suggest that the thermal extraction of lowrank coals strongly depends on the cross-links rather than the hydrogen bonds. Therefore, the thermal extraction yields of low- rank coals can be estimated from the quantity of COOM in the original coals. The intercept of the regression line between the quantity of COOM and the extraction yield with CMNO was 57.8%. This value is the average extraction yield for low- rank coals with free COOM.

Abstract  Infinite dilution activity coefficients y(i)(infinity) have been measured for various solutes (alkanes. alkenes. cycloalkanes, cycloalkenes. aromatics. alcohols, ketones, esters, ethers, and water) in the five ionic liquids 1-methyl-3-methyl-imidazolium methylsulfate [MMIM](+)[CH3SO4](-). 1-methyl-3-methyl-imidazolium methoxyethylsulfate [MMIM](+)[CH3OC2H4SO4](-). 1-methyl-3-methyl-imidazolium dimethylphosphate [MMIM](+)[(CH3)=PO4](-), N-ethylpyridinium bis(trifluoromethylsulfonyl) imide [C5H5NC2H5](+)[(CF3SO2)(2)N](-), and pyridiniumethoxyethylsulfate [C5H5NH](+)[C2H5OC2H4OSO3](-) in the temperature range from 303.15 to 373.15 K. Additionally. densities of the investigated ionic liquids were measured in the temperature range from 293.15 to 353.15 K. Using all available gamma(i)(infinity)-data, the selectivities S-ij(infinity)= gamma(i)(infinity)/gamma(i)(infinity) and the capacities k(i)(infinity) = 1/gamma(i)(infinity) at infinite dilution were determined for different separation problems not only for ionic liquids, but also N-methyl-2-pyrrolidone (NMP) and ethylene glycol. (C) 2004 Elsevier B.V All rights reserved.

Abstract  We used X-ray photoelectron spectroscopy (XPS) to examine structural changes in the chemical form of nitrogen in coal induced by thermal extraction with organic or industrial solvents (HyperCoal (HPC) production). Changes during solvent extraction depended on the chemical form of nitrogen in the coal. HyperCoal nitrogen primarily consisted of pyrrole nitrogen (pyrrole-N), with less pyridine nitrogen (pyridine-N) and no quaternary nitrogen (quaternary-N). The extracted residue contained pyridine-N and quaternary-N as well as pyrrole-N. Quaternary-N decreased during extraction, while the amount of pyridine-N increased, and relatively a little change was observed in pyrrole-N. It is thought that much of the quaternary-N decomposed during thermal extraction and was converted to pyridine-N. (C) 2012 Elsevier B.V. All rights reserved.