N-methyl Pyrollidone Research Articles

Diaminoethane-crosslinked polyetherimide nanofiltration membrane for textile wastewater dye removal

In this work, diaminoethane (DAE) is applied to improve the properties of polyetherimide (PEI) nanofiltration (NF) membranes via crosslinking process with the core objective of removal of textile dye from wastewater. The membranes were fabricated by phase inversion thin film casting technique, from PEI/acetone/NMP (n-methyl pyrollidone) dope solution, crosslinked with DAE 2.5 % v/v in methanol. The novelty of this study is that DAE has never been utilized to crosslink PEI NF membrane for removal of dye from textile wastewater. In this study, the parameters of composition of polyetherimide dope solution having acetone as non-solvent content are investigated to obtain a potential membrane for clarifying wastewater, which is one of major problems in Indonesia. A model dye was utilized, namely Reactive Red 120 (RR120) as a synthetic wastewater. It is found that the rejection of dye is increased along with the acetone content, and also by the crosslinking duration. The crosslinking between PEI and DAE is analyzed from the physical and chemical aspects, by using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR), respectively. A good performance in nanofiltration of RR120 synthetic dye wastewater is demonstrated with 92-98% dye rejection, which is quite reasonable compared to previous researches. This PEI-DAE NF is therefore promising not just for sustainable waste management, but also for the innovation and development in the ecology and environment of Indonesia.

Ultrasonication-assisted ultrafast solvothermal reduction of graphene oxide

Solvothermal reduction of graphene oxide (GO) is one of the suitable way to prepare a dispersion of reduced graphene oxide (RGO) in organic solvents that is stable at high concentration without surfactants. However, it is a long-term process and often requires elevated pressure. Ultrasonic irradiation of GO dispersion in N-methylpyrollidone (NMP) at high temperature promotes full reduction of GO in ten minutes, which is several decade faster than conventional solvothermal reduction of GO. Synthesized RGO was characterized by XRD, Raman, FTIR and XPS methods.

Enhancement of Polymer Powder Wettability by Using Surface Dielectric Barrier Discharge

The surface of 180- $\mu \text{m}$ polyethylene (PE) and 200-nm polytetrafluoroethylene (PTFE) powders are hydrophilized by using surface dielectric barrier discharge (sDBD) applied to a batch of 20 g for both cases. On the sDBD electrode, charged particles by plasma generation are able to diffuse onto the power surface through small voids. In order to know the level of hydrophilic treatment on the powder, absorption tests by using droplet was carried out. This principle is based on the fact that the inner gap between powders are small enough that a liquid with a certain surface tension is absorbed or formed on powder layer when dropped on the powder surface. The minimum isopropyl alcohol (IPA) concentration absorbed into the powder was measured by an aqueous solution with a mixture of IPA and D.I water. By lowering the IPA concentration, improvements in the hydrophilicity were obtained. The concentration of IPA before treatment of PE powder was 15% and decreased to 3% after treatment. In the case of PTFE, IPA concentration decreased slightly from 39% to 30% after the treatment. Also, the surface treated PE and PTFE displays a significant difference in the degree of dispersion in water and n-methyl pyrollidone solvent. In the field-emission scanning electron microscope analysis, the morphology of the treated surface was clean. From composition of the surface by X-ray photoelectron spectroscopy, when the untreated sample is 100% C–H, the plasma treated PE shows 82.48% C–H, and 17.52% C–O. A partial change in the C–F bond is shown for PTFE.

Polyetherimide thin film composite (PEI-TFC) membranes for nanofiltration treatment of dyes wastewater

In our previous work, a series of polyetherimide (PEI) nanofiltration membranes has been developed for removal of textile dyes from wastewater. Based on that previous study, another class of PEI-based membrane was developed for sustainable eco-engineering development in Indonesia, namely polyetherimide thin film composite (PEI-TFC) membranes. These PEI-TFC membranes were fabricated from dope solution consists of PEI dissolved in N-methyl pyrollidone (NMP) solvent and acetone as a non-solvent. The dope solutions were then continued to the membrane casting process, followed by solvent exchange process to remove the residual NMP in the pores of the membranes. The cast membranes were then immersed in 1.5% w/w m-phenylenediamine (MPD) in deionized water, followed by immersion in (0.05% w/w trimesoyl chloride in hexane). Those chemicals act as precursor to form a polymeric thin film in a process called interfacial polymerization to attach TFC layer on top of the PEI-TFC membranes. The fabricated PEI-TFC membranes were employed to treat synthetic wastewater containing Reactive Red 120 dye (RR120), with good rejection of 90%. The membranes could be further explored for the improvement of environmental sustainability of Indonesia, especially for the water ecology system.

Design of experiments to optimize the extraction parameters of a power grade Indian coal

Low grade high ash coals with difficult physical washability characteristics require chemical cleaning techniques such as solvent extraction to obtain super clean coal with lower ash contents. Kedla, an Indian low grade coal has ash content around 44%–50% and there is a need to maximize its solvent extraction yield so as to make this power grade coal industrially useful. This paper highlights the use of definitive screening design and response surface methodology to extract the maximum organic matter from Kedla coal using ethylenediammine (EDA) and N-methyl pyrollidone (NMP) as solvents under mild atmospheric pressure conditions. The coal was pre-treated with acetic acid before extractions were carried out. The parameters such as the acid pre-treatment time, acid concentration, particle size, the co-solvent concentration and the solvent concentration were optimized in this paper. With this design of experiments technique about 40% of the organic matter with minimal ash (less than 2%) content was rendered extractable unlike the already postulated designer solvent system—e, N system (i.e. NMP containing small amount of EDA) that uses coal to solvent ratio as 1:17 (wt/vol) and coal to co-solvent ratio as 1:1(wt/vol) thus only giving 19% extraction yield. Therefore, the present design of experiments technique helps in conserving the number of experiments for process intensification.

In situ growth of multilayered crystals in amorphous matrix: Thermal, dynamic mechanical, and morphological analysis of nylon‐6/epoxy composites

ABSTRACTA new procedure for processing of epoxy/polyamide blend was explored via solution polymerization of ε‐caprolactam in N‐methylpyrollidone (NMP), which resulted in a suspension of nylon‐6 in solvent at room temperature. The suspension was blended with water based epoxy resin using mechanical stirring at room temperature. Several films were prepared from blend by varying the amount of nylon‐6 without curing agent. All films were fully characterized for thermal and dynamic mechanical properties using differential scanning calorimetry and dynamic mechanical analysis. The addition of nylon‐6 had a plasticizing effect on epoxy evident by decrease in glass transition temperature (Tg). The reaction between nylon‐6 and epoxy was studied using Fourier transform infrared spectroscopy by following the characteristic epoxy peak (914 cm−1). The growth of nylon‐6 crystals in epoxy matrix lead to spherulitic multiphase morphology, which was observed under scanning electron microscope. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3319–3327, 2013

Retraction: Facile Palladium‐Catalyzed Arylation of Heterocycles and Nonactivated Arenes with Aryl Chlorides

Retraction: Facile Palladium‐Catalyzed Arylation of Heterocycles and Nonactivated Arenes with Aryl Chlorides

Novel Impact of Wet Dosages of NMP in Extraction for Production of High BMCI Carbon Black Feedstocks

In separation sciences, “Solvent Extraction” is one of the most important unit operations, a very widely used process, next only to distillation. In the petroleum refining industry, solvent extraction is commonly widely applied to produce a number of specialty products such as BTX, lube base oils, waxes, etc. There are many solvents used in various separation processes, like sulfolane, phenol, furfural, ketones, and N-methyl pyrollidone (NMP). NMP in particular is an environmentally benign, new generation solvent, which can be tailored for specific separations by using it in conjunction with small doses of water. In recent years, researchers are re-looking at the separation processes and their modifications to exploit these for producing high-value industrial products from low-value refinery streams. The present study deals with the production of high-quality carbon black feedstocks (CBFS) from clarified oils. The study shows the beneficial effect of using NMP in combination with different dosages of water as extraction solvent to extract low-value clarified oil, a cracked material from the FCC unit of an operating Indian refinery. In the present study, water ranging from 0.3 wt% to 10 wt% was used with NMP to produce aromatic extract of BMCI (Bureau of Mines Correlation Index) up to 146 through liquid-liquid equilibrium and mass transfer studies on clarified oil (CLO). The effect of solvent-to-feed ratio at constant temperature on solvent extraction was also studied. The addition of water in NMP alters the “selectivity” of solvent, which can be exploited for producing aromatic extracts of a wide range of BMCI for different end-use applications. The major users of such high BMCI extracts are carbon black and electrode pitch manufacturers. Regression analysis was also done to develop correlations between water percentage in NMP and targeted BMCI of aromatic extract. Presently, CLO is blended with fuel oil and sold as a very low value product in refinery. Since the demand of CBFS is increasing continuously and current short-fall in India is met through imports from China, Korea, and Japan, it is desirable that such studies are undertaken and will lead to production of high-value CBFS from low-value refinery streams through separation processes.

Synthesis and properties of fluorinated polyimides. 3. Derived from novel 1,3-bis[3′-trifluoromethyl-4′(4″-amino benzoxy) benzyl] benzene and 4,4-bis[3′-trifluoromethyl-4′(4-amino benzoxy) benzyl] biphenyl

Novel diamine monomers, 1,3-bis[3′-trifluoromethyl-4′(4″-amino benzoxy) benzyl] benzene (IV) and 4,4-bis[3′-trifluoromethyl-4′(4-amino benzoxy) benzyl] biphenyl (V) have been synthesized. These monomers lead to several novel fluorinated polyimides on reaction with different commercially available dianhydrides like pyromellatic dianhydride (PMDA), benzophenone tetracarboxylic acid dianhydride (BTDA) or 2,2-bis(3,4-dicarboxyphenyl) hexafluoropropane (6FDA). The polyimides prepared from above two monomers on reaction with 6FDA are soluble in several organic solvents such as N, N-dimethyl formamide (DMF), N, N-dimethyl acetamide (DMAc) and tetrahydrofuran (THF). The polyimides prepared from PMDA/IV is soluble in DMF and N-methyl pyrollidone (NMP) on heating, whereas V/PMDA is insoluble in all solvents. BTDA/IV polyimide is also soluble in NMP, DMF and DMAc. These polyimide films have low water absorption rate 0.2–0.7% and low dielectric constant 2.74–3.2 at 1 MHz. These polyimides showed very high thermal stability even up to 531 °C for 5% weight loss in synthetic air and glass transition temperature up to 316 °C (by DSC) in nitrogen. All polyimides formed tough transparent films, with tensile strength up to 148 MPa, a modulus of elasticity up to 2.6 GPa and elongation at break up to 31% depending upon the exact repeating unit structure.

Synthesis and properties of fluorinated polyimides, 2

Novel diamine monomers, 2,6-bis(3'-trifluoromethyl-p-aminobiphenyl ether)pyridine (TABP) and 2,5- bis(3'-trifluoromethyl-p-aminobiphenyl ether)thiophene (TABT) have been synthesized, which lead to a number of novel fluorinated polyimides by thermal imidization routes when reacted with different commercially available dianhydrides like pyromellitic dianhydride (PMDA), benzophenone tetracarboxylic acid dianhydride (BTDA) or 2,2-bis(3,4- dicarboxyphenyl) hexafluoropropane (6FDA). The polyimides ABTP/6FDA and ABTT/6FDA are soluble in several organic solvents such as N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc) and tetrahydrofuran (THF). The polyimide ABTP/PMDA is only soluble in N- methylpyrollidone (NMP) whereas ABTT/PMDA is insoluble in all solvents. The polyimides ABTP/6FDA (2c) and ABTT/6FDA (3c) exhibited number-average molecular weight 32 940 (polydispersity index (PDI), 1.97) and 24 760 (PDI, 1.87) respectively. These polyimide films have low water absorption rate 0.3-0.9% and low dielectric constant 2.92-3.29 at 1 MHz. These polyimides showed very high thermal stability even up to 532 °C for 5% weight loss in synthetic air and glass transition temperature up to 287 °C (by DSC) in nitrogen. All polyimides formed tough transparent films, with tensile strength up to 115 MPa, a modulus of elasticity up to 2.91 GPa and elongation at break up to 12% depending upon the exact repeating unit structure.

Electrochemical properties of polymer gel electrolytes based on poly(vinylidene fluoride) copolymer and homopolymer

Polymer gel electrolytes were prepared by soaking poly(vinylidene fluoride) (PVdF) membranes, obtained by casting solutions of PVdF copolymer or homopolymers in a solvent such as acetone, tetrahydrofuran (THF), methyl ethyl ketone (MEK) and N-methylpyrollidone (NMP), into an electrolyte solution of 1 M LiBF 4 in propylene carbonate (PC). During the casting process, phase separation occurred leading to non- or low-porous membranes when the phase separation remained in its early stage or to highly porous membranes when it was mostly achieved. The phase separation was enhanced with the increase in the polymer crystallinity and was more significant in the case of the homopolymers. The membranes cast from NMP solutions were non- or low-porous and showed very low uptakes of the electrolyte solution and low conductivity. In this case, the copolymer showed higher uptakes of the electrolyte solution than the homopolymers. It was also found that even for an equivalent uptake of the electrolyte solution the conductivity was higher for the copolymer than the homopolymer, attributable to the lowest crystallinity of the copolymer. On the contrary, the membranes obtained from MEK solutions with slow evaporation rates were highly porous for the homopolymers and absorb much more electrolyte solution than non- or low-porous membranes. The polymer electrolytes from the porous membranes exhibited conductivity of 10 −3 S/cm at 30°C. The phase separation process was very important since it allowed a higher uptake of the electrolyte solution and thus a higher conductivity. Nevertheless, increasing porosity affected the mechanical properties of the membranes when it exceeded 50% of the total volume. The principal limitation of the uptake of electrolyte was caused by the loss of mechanical strength. Concerning the potential window and the evolution of the interfacial resistance at the Li/polymer electrolyte interface, no significant difference could be pointed out between the copolymer and the homopolymers.

Lyotropic behaviour of liquid crystalline poly(ester amide) containing diamide links

The lyotropic behaviour of a poly(ester amide) (PEA), poly[bis (terephthalate butyramide) hexane] (PBTBH) containing aliphatic diamide links prepared through the amido diol route was studied by isothermal viscosity measurements at different shear rates and cross polarized light microscopic measurements in m-cresol, N-methyl pyrollidone (NMP) and concentrated sulphuric acid. The effects of polarity of solvent, shear rate and polydispersity on the threshold concentration were investigated. The viscosity values of the liquid crystalline (l.c.) PEA were found to increase with increase in concentration, reach a maximum and then decrease sharply. The critical concentration at which the viscosity–concentration curve shows a maximum and the threshold concentration where maximum anisotropy was observed did not coincide. The threshold concentrations in the viscosity-concentration curve obtained for the PEA are 56, 54 and 50 wt%, respectively, in m-cresol, NMP and concentrated sulphuric acid. The present experiments show that the threshold concentration depends on the polarity of the solvent, shear rate and polydispersity of the polymer. A narrow molecular weight distribution gives a sharper peak with a lower threshold concentration. PBTBH exhibited the typical shear thinning region under low shear rate peculiar to l.c. polymer solutions. The Newtonian plateau and the second shear thinning region under higher shear rate were also observed. Region I behaviour was confirmed by a number of observations, namely (a) the lack of scaling of transient viscosities during startup with strain and (b) the strong dependence of D 0 on concentration. In Region I, the viscosity showed a mild dependence on shear rate. This corresponds to a decrease of texture size with shear rate approximately as D −1/2, as in the Wissbrun model. The formation of the l.c. phase was confirmed by polarized light microscopy. Appearance of anisotropic inclusions in an isotropic phase started appearing prior to the occurrence of the critical concentration. As the concentration of anisotropic phase increased, the well known ‘phase inversion’ took place and isotropic inclusions in anisotropic phase started appearing as the system approached the threshold concentration. A fully anisotropic phase above the threshold concentration gave the typical nematic threaded texture under the polarized light microscope. A polydomain microstructure was observed in the shear thinning region under low shear rate, which tumbled down to a monodomain structure on application of higher stress.

Synthesis of polyamide-imide by blocked-methylene diisocyanates

The synthesis of polyamide-imide (PAI) can be performed by the reaction of p-chlorophenol-(PCP) blocked 4,4′-diphenyl methane diisocyanates (BMDI) with trimellitic anhydride (TMA) using a two-stage heating. At 80°C the polyimide oligomers were first formed and the high molecular weight PAI can not be available until the temperature was increased to 120°C and stayed for 3 h, during which the amide groups were formed and the molecular weight was increased. The molecular weights of the synthesized PAIs on various conditions were analyzed by measuring the intrinsic viscosity, amide/imide ratio from IR spectra, and average chain length from GPC. The best reaction conditions for obtaining a high molecular weight PAI by the solution polymerization are: (a) using N-methyl pyrollidone (NMP) as solvent, (b) adding more BMDI/TMA ratio, and (c) adding tert-n-butyl amine as the catalyst for the dissociation of blocked MDI and controlling the catalyst concentration at 0.162M. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 1711–1717, 1997

Studies in piperazine containing poly(sulphone-amide)s for use in water desalination

Poly(sulphone-amide) polymers were prepared from reactions of 4,4′-diaminodiphenylsulphone (DDS) and piperazine with isophthaloyl chloride (ICl) or terephthaloyl chloride (TCl) in N-methylpyrollidone (NMP) by low temperature polycondensation. Properties such as inherent viscosity, percent moisture regain, percent solubility in different solvents, chlorine absorbance and thermal analysis were studied. Membranes were cast from solutions of these polymers in N, N′-dimethylacetamide (DMAC) containing dissolved lithium chloride/calcium chloride/lithium nitrate as additive salts. The reverse osmosis (RO) membrane performances were evaluated using aqueous sodium chloride feeds with and without chlorine addition at 70 kg·cm −2 operating pressure.

Effect of overcoats on environmental stability of a chemically amplified positive resist against water and organic bases.

The effect of two kinds of overcoats on stabilizing the resist during post-exposure delay is evaluated in the presence of water and organic bases. Organic-soluble poly(α-methylstyrene) is more effective in preventing water penetration than poly(acrylic acid), which is a water- soluble overcoat. On the other hand, poly(acrylic acid) is more effective against organic bases such as aniline and N-methyl pyrollidone (NMP).This is probably because the negative charge of the carboxyl groups in poly(acrylic acid) electrically traps aniline and NMP, preventing their penetration to the resist films.

Transport properties of polyimide/silica composite membranes.

Polyimide/silica composite membranes were prepared by the sol-gel reaction of tetraethoxysilane, methyltriethoxysilane or phenyltriethoxysilane in the solution of polyamic acid prepared by condensation of equimolar amount of pyromellitic dianhydride, 3, 3′, 4, 4′-biphenyltetracarboxylic dianhydride or 2, 2-bis(3, 4-dicarboxyphenyl)hexafluoropropane dianhydride with 4, 4′-oxydianiline in N-methyl pyrollidone. Silica-coated polyimide membranes were also prepared by the sol-gel method. Gas permeation for H2, CO2, CO, O2, N2 and CH4 and water vapor permeation were reported. A slight reduction in gas permeability was observed for the composite membrane. The permeability of water vapor increased in polyimide/silica composite membranes, while silica coating resulted in a reduction of the permeability. Transient sorption and desorption experiments were also investigated at water vapor activity of 0.5. An increase in permeability of water vapor can be attributable to an increase in solubility of water vapor due to the presence of hydroxy species of silica.

The stabilisation and characterisation by infrared spectroscopy of the different bonding modes of copper(I) thiocyanate adsorbed on high surface area solids

High surface area solids such as alumina, silica or charcoal, have been used to stabilise the various bonding modes of copper(I) thiocyanate. Infrared spectroscopy was used to characterise the different species, for example on alumina sulfur bonded, nitrogen bonded and bridged thiocyanate species were observed. The effect of the high surface area solid was in some cases dramatic and the bonding modes stabilised were found to be dependent upon the concentration of the impregnating solution, relative to the amount of high surface area solid present. The most striking differences were between charcoal and the other two solids, in the former case high loadings of copper(I) thiocyanate resulted in stabilisation of a bridged species, whereas only low loadings of copper(I) thiocyanate on alumina or silica resulted in stabilisation of a bridged thiocyanate species. Both nitrogen and sulfur bonded thiocyanate species were evident on all the supports. The N-bonded species were generated in dimethyl sulfoxide solvent before impregnation onto the solids, whereas the S-bonded species were generated in either N-methyl pyrollidone or aqueous KSCN prior to impregnation. The effect of the high surface area solid manifests itself in the reaction chemistry of copper(I) thiocyanate with 1-iodo-2-nitrobenzene (an ipso substitution reaction) by altering the proportion of aryl isothiocyanate to aryl thiocyanate to aryl nitrile products.

Polysulfone Modified Thermoplastic Polyimide Segmented Copolymer Matrix Resin Systems

Several methods have been investigated which improve the processability of polyimide homo- or copolymer systems. In particular, the utilization of a solution imidiza tion technique in converting the poly(amic acid) intermediate to the fully cyclized polyimide has been successfully exploited. The solution imidization was conducted in N- methylpyrollidone (NMP) and an azeotroping agent, such as cyclohexylpyrollidone (CHP), at approximately 160°C for 24 hours. This technique has been shown to yield more soluble products than the corresponding bulk thermal imidization which is con ducted at higher temperatures of ∼300°C. Another important method of improving melt as well as solution processability involves the incorporation of a monofunctional reagent to obtain nonreactive end groups and controlled molecular weights. Structural modifica tion by copolymerization with more flexible oligomers such as poly(arylene ether)s may also enhance processability and possibly provide improved impact strength. In this paper, the effects of incorporating varying concentrations of poly(arylene ether) sulfone and ketone oligomers into the polyimide backbone are reported. The overall copolymer molecular weight was consistently controlled to —25,000 g/mole, with the use of small molar quantities of the monofunctional reagent phthalic anhydride. Very tough, trans parent films were obtained in all cases by compression molding copolymers at 340°C. Thermal analysis indicated that microphase separation is achievable in some cases as judged by the presence of two glass transition temperatures.

The study of the kinetics of formation of poly(amido) acids for carding

The kinetics of formation of poly (amino)acids based on carding diamine-9,9-bis-4′-aminophenylfluorene and 3,3′,4,4′-tetracarboxydiphenylsulphonic acid dianhydride (I), the dianhydrides of 3,3′,4,4′-tetracarboxybenzophenone (II), pyromellitic acid (III), 2,3,7,8-tetracarboxy-10,10-dimethylphenoxasilene, 3′,3″,4′,4″-tetracarboxydiphenyloxide, 3,3′,4,4′-tetracarboxydiphenyldimethylsilane, or 1,4-bis-(3,4-dicarboxy-α-cumyl)benzene, in N-methyl pyrollidone (MP) were studied by UV spectroscopy as changes of the amino group concentrations. The reaction rate has been found to increase on changing from the less polar solvent (dioxane) to the more polar MP, and also when water and carboxylic acids were added. The use of the more reactive anhydrides I, II or III was found to increase the rate of the main as well as of the secondary reactions, for example those with MP.