SOLUBILITY OF LAMOTRIGINE IN BINARY AND TERNARY MIXTURES OF PEGS 200, 400, AND 600 WITH ETHANOL,PG, AND WATER AT 298.2 K

Experimental solubilities of 6-(2,3-dichlorophenyl)-1,2,4-triazine-3,5-diamine (lamotrigine) in binary and ternary solvents of polyethylene glycols (PEGs) 200, 400, and 600 with ethanol and water, and PEGs 200, 400, and 600 with propylene glycol (PG) and water at T = 298.2 K are reported. The Jouyban-Acree model was used to fit solubility data of lamotrigine in the binary and ternary solvent mixtures (145 data points) in which the overall mean relative deviation (OMRD %) was 11.5%. The density of the solute-free solvent mixtures was measured and employed to calculate the constants of the Jouyban-Acree model and then the density of the saturated solutions is predicted.     

Preferential Solvation of Indomethacin in Some Aqueous Co-Solvent Mixtures

The preferential solvation parameters for indomethacin (IMC) in ethanol (EtOH) + water and propylene glycol (PG) + water binary mixtures were obtained from their thermodynamic properties by means of the inverse Kirkwood–Buff integrals (IKBI) and the quasi-lattice quasi-chemical (QLQC) methods. According to IKBI method, the preferential solvation parameter by co-solvents, (δx_1,3), is negative in the water-rich mixtures of both binary systems but positive in the other compositions at temperatures of 293.15, 303.15, and 313.15 K. It is conjecturable that in water-rich mixtures the hydrophobic hydration around the aromatic rings and methyl groups of the drug plays a relevant role in the solvation. The higher drug solvation by co-solvent in mixtures of similar solvent proportion and in co-solvent-rich mixtures could be due mainly to polarity effects. Here IMC would be acting as a Lewis acid with the EtOH or PG molecules because these co-solvents are more basic than water.     

MOLECULAR WEIGHT EFFECTS OF THE SOFT SEGMENT ON THE ULTIMATE PROPERTIES OF LIGNIN-DERIVED POLYURETHANES

Polyurethane (PU) films were prepared by solution casting using a three-component system, namely a novel semi-rigid solvolytic lignin, soft segment and a co-monomer. In the present study, the effects of varying the chain length of polyethylene glycol (as the soft segment) were investigated to produce lignin-based polyurethanes with variable thermal and mechanical properties. An important objective was to incorporate as much lignin as possible. The polyethylene glycol (PEG) studied included 5 different molecular weights (200, 400, 1000, 1500 and 2000 g/mol). The polyurethane films, prepared by solvent casting, were evaluated for crosslink density, and ultimate mechanical and thermal properties. Results showed that the films derived from the PEG 200 were either too weak or brittle to be tested. It was found that the PEG (400, 1000, and 1500) are better choices for producing polyurethanes from the solvolysis lignin studied. Crosslink densities of PU films using the 400, 1000 and 1500 were determined to be in the range of 0.8–2.6 mmol/cm³, which is a lower range than those of films from PEG 2000, namely 2.4–2.8 mmol/cm³. Also, the ultimate tensile strength decreased from about 50 MPa at high lignin content for PEG 400, 1000 and 1500 to about 18 MPa for PEG 2000 at low content of lignin. Ultimate strain also decreased from the 30.9–62.7% range for the PEG 400 to 1500 series at low lignin content down to about 4% for PEG 2000 at high lignin content. Young's Modulus varied from a high of 2 GPa (PEG 400, lignin content = 30 wt%) down to 0.6 GPa (PEG 2000, lignin content = 20 wt%). The glass transition temperature was found to decrease from 108°C to about 45°C with increasing molecular weight of PEG for a lignin content of 30 wt% and an NCO/OH of 1.2. The data are consistent with the percolation theory approach to network formation, as well as the notion that the network itself consists of relatively large and stiff islands, each comprising many branch points, held together by a soft and pliable matrix.     

KINEMATIC VISCOSITIES OF POLYETHYLENE GLYCOL DEXTRAN WATER SOLUTIONS

The kinematic viscosities of aqueous polyethylene glycol and dextran and polyethylene glycol + dextran + water were measured at temperatures of 30, 50, and 70°C. Polyethylene glycol with relative molecular masses of 200 and 1000 and dextran samples with nominal molecular masses of 37 500 and 2 000 000 were used. A one-parameter Grunberg-like equation proposed earlier by one of the present authors was used for estimating the values of viscosity of polyethylene glycol + dextran + water. A disposable parameter for the temperature range was calculated as 0.96 and 1.05 for PEG 200 + dextran 37 500 + water and PEG 1000 + dextran 37 500 + water, respectively, and as 2.74 and 2.80 for PEG 200 + dextran 2 000 000 + water, and PEG 1000 + dextran 2 000 000 + water, respectively. In view of our results, the proposed model works well for systems containing polyethylene glycol and dextran with different molecular masses.     

The Effect of Glycol Type,Glycol Mixture,and Isocyanate/Glycol Ratio on Flexural Properties of Oil Palm Empty Fruit Bunch-Polyurethane Composites

Abstract

Oil palm empty fruit bunch (EFB)-polyurethane (PU) composites were produced. The effects of the isocyanate (NCO)/glycol (OH) ratio, glycol type, and mixtures (polyethylene glycol PEG 400 (M _w 400) and polypropylene glycol PPG 400 (M _w 400)) on the flexural properties were investigated. The NCO/OH ratio had a significant effect on the flexural properties of the EFB-PU composites. Composites made with PEG 200 exhibited higher flexural properties than with PEG 400 and PPG 400. The flexural properties were also found to be influenced by the PPG 400/PEG 400 ratio.     

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

Abstract

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

Solubility and Apparent Specific Volume of Some Pharmaceutical Salts in Propylene Glycol + Water Mixtures at 298.15 K

The equilibrium solubility of three pharmaceutical salts, namely, sodium naproxen (Na.NAP), procaine hydrochloride (PC.HCl), and lysine clonixinate (Lys.Clon), was determined in propylene glycol (PG) + water mixtures at 298.15 K. If the mole fraction concentration scale is considered, the mixtures’ composition-dependence on solubility was different for these drugs. Thus, the solubility of Na.NAP increased nonlinearly from pure water to pure PG. By contrast, the solubility of PC.HCl decreased nonlinearly from pure water to pure PG. In a different way, the solubility of Lys.Clon increased from pure water to the mixture with mass fraction of PG, w₁ = 0.80, and later, it decreased to reach a lower value in pure PG. A good correlation of the solubility data was obtained by using the modified NIBS/R-K model. Otherwise, the apparent specific volumes at saturation of these drugs were also calculated in all the mixtures under study.     

The Effect of PEG on the Water Absorption Capacity and Rate of Superabsorbent Copolymers Based on Acrylic Acid

ABSTRACT

In this study, acrylic acid–based superabsorbent copolymers were synthesized with different comonomers (PEGs) by inverse suspension polymerization technique. The said superabsorbent copolymers were obtained from the aqueous solution of monomers dispersed in a continuous organic phase. The inverse suspension polymerization was accomplished by the use of aqueous solutions of partly neutralized acrylic acid with a predetermined crosslinker agent/monomer ratio in cyclohexane. Sorbitan monostearate was used as a surfactant, ethylene glycol dimethacrylate (EGDM) either as a comonomer or a crosslinking agent, potassium persulfate as the initiator, and polyethylene glycols (PEG 200, PEG 1000, PEG 4000) were used as pore-making agents. The copolymers (SAPs) were characterized by IR spectroscopy and SEM micrographs. Effect of PEGs on the water absorption capacity, rate of absorption to reach equilibrium, and the time needed to release the water absorbed from the gels were investigated. It was observed that the copolymer based on EGDM-Na acrylate + PEG4000 (A3) gave better results than the other copolyemrs.     

Effects of PEG on Morphology and Permeation Properties of Polyethersulfone Membranes

Abstract

Flat sheet asymmetric polyethersulfone (PES) ultrafiltration (UF) membranes were prepared from a homogenous solution of PES via immersion precipitation in a water coagulation bath. The effect of the solvents (N-methyl-2-pyrrolidone (NMP) and N,N-dimethylformamide (DMF)) in preparation of the casting solution was studied. The effects of the molecular weight of polyethylene glycol (PEG) (400, 1500, and 6000 Da) on the morphology and the permeation properties of PES membranes were also investigated. Surface and cross-sectional morphology of the prepared membranes were studied by Scanning electron microscopy (SEM). The permeation performance of the prepared membranes was evaluated in terms of pure water flux (J_w), water content, porosity, hydraulic permeability, protein solution flux, and protein rejection. A solution of human serum albumin (HSA, Mw = 66,000 Da) was used as feed to study the permeation properties of the prepared membranes. Increasing molecular weight of PEG additives from 400 to 6000 Da enhances pure water permeation flux and HSA solution permeation flux while it reduces the protein rejection.     

Chlorogenic Acid Containing Bioinspired Polyurethanes: Biodegradable Medical Adhesive Materials

Highly adhesive bioinspired polyurethanes (PUs) based on the chlorogenic acid (CLA) were prepared from 4,4′-methylenebis(cyclohexyl isocyanate) (MCI) and polyethylene glycol 200 (PEG 200). The polyurethanes exhibited the lowest glass transition temperature (T_g), improved thermal stability and good adhesive properties. The highest adhesion strength was found as 373.3 ± 47.5 kPa for 10% CLA containing PUs. The polyurethanes were observed to be biodegradable and were in the range of 19–24% for 8 weeks as depending on chlorogenic acid containing of PUs. As a result, prepared biocompatible-adhesive bioinspired polyurethanes are good candidates for medical applications as a tissue adhesive material.     

Specialty polymeric membranes, 7. Pervaporation separation of benzene/cyclohexane mixtures with nylon 6-graft-poly(oxyethylene) membranes

Novel membrane materials for pervaporation separation of benzene/cyclohexane mixtures were prepared by the introduction of oligo(oxyethylene)s, such as diethylene glycol, poly(ethylene glycol) 200 (PEG200) and poly(ethylene glycol) 400 (PEG400) onto Nylon 6. The polymeric membranes from modified Nylon 6 thus prepared showed permselectivity toward benzene. Some membranes exclusively permeated benzene from benzene/cyclohexane mixture.     

Oil Palm Empty Fruit Bunch‐Polyurethane Composites: The Effect of Isocyanate/Glycol Ratio,Glycol Type,and Glycol Mixture on Impact Strength,Dimensional Stability,and Thermal Properties

Abstract

In this study, polyurethane (PU) composites have been produced with oil palm empty fruit bunch (EFB) and polyethylene glycol (PEG), molecular weight (MW) of 200 (PEG200), 400 (PEG400), and polypropylene glycol (PPG) with MW of 400 (PPG400) used as polyols. The effect of isocyanate (NCO)/hydroxyl (OH) ratio and PPG400/PEG400 ratio on the impact strength, dimensional stability (immersion test), and thermal behavior were investigated. The study revealed that as the NCO/OH ratio was increased, the impact strength increased, and the absorption and swelling of the composites either in water or dimethylformamide (DMF) decreased. The decrease in the onset and peak temperatures, and the increase in the enthalpy as the NCO/OH ratio was increased from 0.8 to 1.1 were attributed to the disruption of crystalline region due to the occurrence of cross‐linking. As for NCO/OH ratio of 1.1 onward, the increase in onset and peak temperatures were due to the increase in the degree of cross‐linking. On the other hand, the decrease in the enthalpy was due to the formation of allophanates. Thermal behavior of the composites made from the glycol mixture was predominantly influenced by the PPG400.     

Microwave dielectric relaxation and molecular dynamics in binary mixtures of poly(propylene glycol) 2000 and poly(ethylene glycol)s of varying molecular weight in dilute solution

Molecular dynamics of binary mixtures of poly(propylene glycol) (PPG) and poly(ethylene glycol)s (PEGs) of varying molecular weight due to molecular interactions, chain coiling and elongation in dilute solution under various conditions, ie varying number of monomer units of PEG, method of mixing of polymers and solvent environment, has been explored using microwave dielectric relaxation times. The average relaxation time τ_o, relaxation time corresponding to segmental motion τ₁ and group rotations τ₂, of a series of binary mixtures of poly(propylene glycol) 2000 and poly(ethylene glycol) of varying molecular weight (ie PPG 2000 + PEG 200, PPG 2000 + PEG 300, PPG 2000 + PEG 400, and PPG 2000 + PEG 600 mixed by equal volume in the pure liquid states, and PPG 2000 + PEG 1500, PPG 2000 + PEG 4000 and PPG 2000 + PEG 6000 mixed equal weights in solvent) have been determined in dilute solution in benzene and carbon tetrachloride at 10.10 GHz and 35 °C. A comparison of the results of these binary systems of highly associating molecules shows that the molecular dynamics corresponding to rotation of a molecule as a whole and segmental motion in dilute solutions are governed by the solvent density when the solutes are mixed in their pure liquid state. Furthermore, the molecular motion is independent of solvent environment when the polymers are added separately in the solvent for the preparation of binary mixtures. It has also been observed that there is a systematic elongation of the dynamic network of the species formed during mixing of pure liquid polymers in lighter environment of solvent with increasing PEG monomer units, while the elongation behaviour of the same species in the heavier environment of carbon tetrachloride solvent is in contrast to the elongation behaviour of the polymeric species formed in pure PEG. The role of rotating methyl side‐groups in the PPG molecular chain has been discussed in term of the breaking and reforming of hydrogen bonds in complex polymeric species for the segmental motion. In all these mixtures, the relaxation time corresponding to group rotations is independent of the solvent environment and constituents of the binary mixtures. The effect of chain flexibility and coiling in these binary mixtures is discussed by comparing the relaxation times of the mixtures with their individual relaxation times in dilute solutions measured earlier in this laboratory. © 2001 Society of Chemical Industry     

Self‐Assembly Behaviors of Anionic–Cationic Binary Surfactant Systems in Poly(ethylene glycol) 200

The self‐assembly behaviors of mixtures of sodium bis(2‐ethylhexyl) sulfosuccinate (AOT) and didodecyl dimethylammonium bromide (DDAB) in polyethylene glycol 200 (PEG 200) and in water were investigated by surface tension, conductivity, steady‐state fluorescence and dynamic light scattering (DLS) methods. The results show that the oppositely charged binary surfactant system can form micelles in PEG 200; the critical micellization concentration (CMC) decreases for the binary system versus those of either surfactant alone. Although there is no charge screening in the PEG 200 system, the CMC values significantly increase and the system does not precipitate or show turbidity at any proportion of AOT to DDAB, while a multiphase composition gap exists in water due to the strong electrostatic attraction. It is speculated that the weak polarity of PEG 200, the decreased solvophobic interaction between the alkyl chain and PEG 200, and the loose structure of the resulting micelles might explain the experimental phenomena. Observed from the values of the interaction parameter, it is found that there are a strong attractive interaction and a synergistic effect between AOT and DDAB in aqueous solution, in comparison, the synergy between them in PEG 200 is very weak.     

SOLUBILITY OF ACETAMINOPHEN AND IBUPROFEN IN BINARY AND TERNARY MIXTURES OF POLYETHYLENE GLYCOLS 200 AND 400, PROPYLENE GLYCOL,AND WATER AT 25°C

The solubilities of acetaminophen and ibuprofen in the mixtures of propylene glycol-water, polyethylene glycols 200- and 400-propylene glycol, and polyethylene glycols 200- and 400-propylene glycol-water (122 data points) at 25°C were determined and mathematically represented by the Jouyban-Acree model. The solubilities were measured using the shake flask method, and the model was used to fit the solubility data of each drug in the solvent mixtures. The density of the solute-free solvent mixtures was measured and the density of the drug-saturated solutions was predicted. The obtained overall mean relative deviations (OMRDs) for fitting the solubility data of acetaminophen and ibuprofen in binary mixtures are 1.5% and 11.7%, respectively. The OMRDs for fitting the solubilities in ternary solvent mixtures for acetaminophen and ibuprofen are 16.3% and 42.0%, respectively, and the OMRD values for predicting all solubilities of acetaminophen and ibuprofen by these trained versions of the Jouyban-Acree model were 5.7% and 20.4%, respectively. The prediction OMRD for the density of saturated solutions was 2.5%.     

Effect of Polyethylene Glycol (PEG) Powder on Compressibility and Microstructural Properties of Sintered α-Alumina

This study examines the effect of various contents of polyethylene glycol (PEG) powders on density, compressibility, and microstructural properties of sintered α-alumina samples. Moreover, the effect of compaction pressure on the green density of the compacts is studied by applying different pressures ranging from 400 to 550 MPa. Samples were prepared by mechanical blending of alumina and various amounts of PEG powders in a Turbula mixer. The binder contents vary from 1 wt.% to 4 wt.%. The as-prepared mixture was compacted in a universal machine at room temperature under the pressure of 6 MPa to produce disk-shaped samples in a pre-compaction step. Experimental results revealed that adding various amounts of PEG powders has a detrimental effect on the green density of alumina pellets and decreases the green density from 1.95 to 1.87 g/cm³. The results also show that sintered density of samples increased by increasing the compaction pressure to pressures higher than 400 MPa. It is observed that a sudden increase in green density has been observed between 450 and 550 MPa.     

Microwave dielectric relaxation in binary mixtures of poly(ethylene glycols) in solution

The average relaxation time τ₀, relaxation times corresponding to segmental motion τ₁ and group rotations τ₂, of a series of binary mixtures of poly(ethylene glycols) (PEG 200+PEG 300, PEG 400+PEG 600, PEG 1500+PEG 4000, PEG 6000+PEG 9000, PEG 200+PEG 1500, PEG 300+PEG 4000, PEG 400+PEG 6000 and PEG 600+PEG 9000) have been carried out in dilute solutions of benzene and carbon tetrachloride at 9·83GHz. The effect on chain flexibility due to inter- and intra-molecular association in these binary mixtures is discussed by comparing relaxation times of these mixtures with their individual relaxation times in solution. It is inferred that the extent of hydrogen bonding in different binary mixtures is not similar and is influenced by solvent environment, but there is correlation between τ₀ and τ₁ values in all these binary mixtures, which may be because of hydrogen bonding. The observed τ₂ values in all these mixtures suggests that the chain-ends remain excluded from the intermolecular association and τ₂ is independent of the polymer constituents of the mixture and solvent. It is also equal to the τ₂ values of the individual polymers. © 1998 SCI.     

Effect of polyethylene glycol molecular weight on cell growth behavior of polyvinyl alcohol/carboxymethyl cellulose/polyethylene glycol hydrogel

Polyvinyl alcohol (PVA)/carboxymethyl cellulose (CMC)/polyethylene glycol (PEG) hydrogel scaffolds are synthesized using cyclic freezing/thawing and subsequent γ-ray irradiation to evaluate the effect of the molecular weights of PEG (200, 400, 1,000, and 2,000) on strength and cell growth behavior of the hydrogels. As the PEG weight increases from 200 to 2,000, the compressive strength and the pore size decreases gradually from 58.0 ± 8.2 kPa to 17.7 ± 6.1 kPa and from 22.7 ± 3.9 μm to 8.5 ± 1.6 μm, respectively. However, the highest swelling rate is obtained for PVA/CMC/PEG400 hydrogels. The irradiated PVA/CMC/PEG400 hydrogels exhibit tailored properties of the swelling rate of 1,148 ± 34.0%, the compressive strength of 42.5 ± 6.6 kPa, the pore size of 14.6 ± 1.9 μm, and cell viability of 184%. In addition, the fastest L-929 cell proliferation and growth with time, verified by the cell proliferation (0–48 hr) and the scratch assay (0–15 hr), was observed for the PVA/CMC/PEG400 hydrogels, indicating that they are highly suitable for potential wound dressings that require fast healing regeneration.     

Removal of nonionic surfactant by systems based on chloromethylated polystyrene–poly(ethylene glycol)

For the purpose of obtaining compounds which can remove nonionic surfactants in water, chloromethylated polystyrene (CMPS) was allowed to react with triethylene glycol monomethyl ether (3EGMME), tetraethylene glycol (4EG), poly(ethylene glycol) (PEG) 200, 400, 600, 1000, and 1500. The amount of PEG groups combined with CMPS decreased with an increase in the molecular weight of PEG. The ability of the product to remove polyethylene glycol mono-p-nonyl phenyl ether (NP, n = 10), a nonionic surfactant, solutes in water was greater in the product with PEG of greater MW than that with PEG of smaller MW, and in the product with more PEG groups (mol/g prod.) than in that with less PEG groups. The removal behavior of the products conformed to Freundlich's adsorption formula. Constants of the formula, the effect of temperature on the constants, the effect of combined PEG groups on the removed amount, and the removal manner were studied.     

Polyethylene glycol-modified poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) counter electrodes for dye-sensitized solar cell

Poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) counter electrodes, doped with polyethylene glycol (PEG) and acetylene black as binding and conductivity promoting agent, were prepared by a simple mixing method for dye-sensitized solar cell. The electrochemical properties of the electrodes were characterized by cyclic voltammetry, electrochemical impedance spectroscopy (EIS), and Tafel polarization curves. Using PEG dopant, the electrocatalytic activity of PEDOT:PSS electrode was much improved, and further improved by adding a small amount of conducting acetylene black (0.2 wt%). The DSSC cells, using the PEDOT:PSS electrode with PEG (5 wt%) dopant and the composite electrode with PEG (5 wt%)/acetylene black, exhibited an energy conversion efficiency of 3.57 and 4.39 %, comparable with 4.50 % of the commonly used Pt electrode under the same experimental conditions. These results demonstrate that PEG-modified PEDOT:PSS counter electrode is promising to replace the expensive Pt for low cost DSSC, especially to meet the large-scale fabrication demands.