Mixture Of Polyethylene Glycol Research Articles

Dimensional Stability of Waterlogged Scots Pine Wood Treated with PEG and Dried Using an Alternative Approach

Low-intensity drying is widely believed to protect waterlogged archeological wood against the adverse effects of dimensional alteration and cracking. However, slow drying generates substantial costs for the conservation process. This study compares the effects on conservation of highly-degraded sapwood (SW) and slightly-degraded heartwood (HW) from waterlogged archeological Scots pine wood treated with polyethylene glycol either as a mixture of polyethylene glycol (PEG) 400/4000 or PEG 2000 solution and air-dried using different approaches. The reference air-drying approach, using gradually decreasing air relative humidity (RH), i.e., 96, 86, 75, 66, and finally 44% (multi-stage schedule), was compared to an alternative approach, using constant RH of 44% (single-stage schedule). The Fourier-transform infrared spectroscopy (FTIR) analysis confirmed the decomposition of hydrophilic chemical wood components and revealed differences in the degree of degradation of waterlogged SW and HW. The drying time of PEG-treated waterlogged wood air-dried using a one-stage schedule was shorter compared to the drying time using multi-stage drying. Multivariate analysis (ANOVA) revealed that the drying schedule used after impregnation of waterlogged wood with PEG can have a beneficial effect on wood hygroscopicity and dimensional stability. The drying schedule significantly affected the equilibrium moisture content (EMC) of SW and HW and reduced tangential (ST) shrinkage of SW. These results show the positive effect of the single-stage alternative drying approach on the dimensional stability of highly-degraded Scots pine SW impregnated with PEG 2000. In the case of slightly-degraded HW, the drying approach did not affect wood preservation. These results can be useful for the conservation of highly-degraded waterlogged Scots pine wood.

Liquefaction of starch using solid-acid catalysts derived from spent coffee for the production of plasticized poly (vinyl alcohol) films

This paper reports a strategy for preparing polyether polyols from corn starch, with (i) a mixture of polyethylene glycol 400 and glycerin (7:3, w/w) as the liquefying solvent and (ii) a spent-coffee-derived solid-acid catalyst (SC-SAC) (1:10, w/w, SC-SAC/starch) at 433 K for 1.5 h, under which conditions the liquefaction yield exceeded 99 %. The SC-SAC was prepared via hydrothermal carbonization at 453 K for 12 h, followed by sulfonation with H2SO4 at 343 K for 10 h. The liquefied starch product (SLP) was then used to plasticize poly(vinyl alcohol) (PVA) films with various mixing ratios. The optimal 0.4 SLP/PVA blend film exhibited good mechanical properties (tensile strength 38.07 MPa, elongation at break 1199 %), good transparency, and excellent flexibility. The results highlight the possibility of using SLP/PVA films in the development of degradable packaging materials.

Co nanoparticles-embedded N, S-codoped hierarchically porous graphene sheets as efficient bifunctional electrocatalysts for oxygen reduction reaction and hydrogen evolution reaction

To develop efficient and low-cost bifunctional electrocatalysts towards oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) is vital for the progress of fuel cell, Zn-air battery and overall water splitting. Herein, a facial method to prepare Co nanoparticles-embedded N, S-codoped hierarchically micro/meso/macroporous graphene sheets (Co@NSCs) via pyrolysis of the mixture of urea, l-cysteine, polyethylene glycol and cobalt (II) nitrate is reported. By controlling the pyrolysis temperature, Co@NSC-1000 obtained at 1000 °C performs comparable electrochemical activity on ORR and HER, with commercial Pt/C. Additionally, Co@NSC-1000 also exhibits acceptable methanol resistance on ORR and admissible long-term durability on ORR and HER after 5000 potential cycles. Synergistically, hierarchically micro/meso/macroporous nanostructure, non-precious Co nanoparticles, and N, S-codoped graphene are greatly contributed to the high electrocatalytic activity and stability. The pyrolysis temperature is the key factor for tailoring element component, nanostructure and electrochemical activities. The competitive catalytic performances on ORR and HER indicate Co@NSC-1000 is a hopeful substitute for noble benchmark Pt catalysts. Furthermore, Zn-air battery assembled with Co@NSC-1000 shows higher specific capacity, larger energy density and stronger stability than Pt/C, holding great potential in practical applications.

Clouding phenomena and thermodynamics of TX-100 + polyethylene glycol mixture: influence of several electrolytes

Herein, the solution properties of Triton X-100 (TX-100) and polyethylene glycol (PEG) mixtures in H2O and salt (potassium, sodium, and ammonium) solutions have been observed through the cloud point (CP) detection technique. The present observation reveals that the values of CP of the TX-100 + PEG mixed solution, in the presence of different salts, undergo a decrease compared to the values found in H2O medium. The anion of common salts, such as sodium, potassium, and ammonium, was found to reduce the values of CP in the sample mixtures in the order: SO42− > Cl− > PO43−. The $$\Delta G_{{\text{c}}}^{0}$$ value was calculated as positive in all experimental cases, and this observation manifests a non-spontaneous nature of clouding system. The non-spontaneity of TX-100 + PEG clouding process was gradually declined with the enhancement of salt concentrations. The $$\Delta H_{{\text{c}}}^{0}$$ and $$\Delta S_{{\text{c}}}^{0}$$ values were found negative, which experience a decrease with the addition of more concentrated salt solutions in almost all of the cases studied. The negative values of $$\Delta H_{{\text{c}}}^{0}$$ and $$\Delta S_{{\text{c}}}^{0}$$ indicate the existence of exothermic interactions (hydrogen bonding and weak dipole–dipole forces) operating between TX-100 and PEG. A linear relationship was established between $$\Delta H_{{\text{c}}}^{0}$$ and $$\Delta S_{{\text{c}}}^{0}$$ with R2 values in the range of 0.9997–1.00.

Investigation of guanidinium acetylacetonate and polyethylene glycol mixture as a new reversible and efficient SO2 absorbent

ABSTRACT Weak basic guanidinium acetylacetonate ([TMG][acac]) was synthesized and blended with PEG200 to construct hybrid absorbent for SO2. The composition was optimized on the basis of viscosity and SO2 absorption performance. For the preferred 20% [TMG][acac]-PEG200 mixture, the effect of various parameters were systematically investigated. Results showed that the maximum mass ratio of SO2 to [TMG][acac] was 0.838 and 0.331 at 30°C for pure and 10% SO2, respectively. The mixture was easily recycled five times. The present SO2 capture process using [TMG][acac]-PEG200 mixtures was a promising method for SO2 removal with both good reversibility and high absorption capacity.

Prediction of Thermal Properties and Reliability Testing of Binary Eutectic Mixture of Polyethylene Glycol 2000 and 10000 as Phase Change Materials

AbstractThis experimental investigation presents the two major aspects of thermal energy storage materials. One is development of eutectic mixtures of polyethylene glycols (PEGs) and another is thermal reliability of them. The commercial grade PEGs with molecular mass 2000 and 10000 were mixed in different mass fractions via facile incorporation method for preparing the eutectic mixtures. The thermal energy storage capacity was measured by using differential scanning calorimeter (DSC) and Fourier transform and infrared spectroscopy (FT‐IR) was adopted to analyse the variation in chemical compositions of eutectics. The eutectics were prepared in the step of 10% mass fraction and characterization show that the mixture of 20% PEG 2000 and 80% PEG 10000 possess the maximum latent heat of fusion, which is 185 kJ/kg. The prepared eutectic mixture was also tested for its durability by in‐house designed thermal cycling tester. The results revealed that this eutectic is able to retain its thermal and chemical properties even after 1500 melting and freezing cycles. The findings of this study show that the prepared binary eutectics are able to be used as potential candidates for passive solar thermal management purposes.

Obtaining and Characterization of a Polydisperse System Used as a Transmembrane Carrier for Isosorbide Derivatives.

Due to their effect of vasodilatation, isosorbide nitrates represent one of the most important and most used solutions for angina pectoris. Unfortunately, these compounds have multiple dose-related adverse drug reactions such as headache, weakness, mild dizziness, and occasionally heart rate changes, nausea, vomiting, and sweating. The main aims of this research were to obtain and to evaluate new polyurethane (PU) structures that can be used as a proper transmembrane carrier with an improved release kinetic. Chitosan-based PU structures were obtained by a polyaddition process between hexamethylene diisocyanate and a mixture of chitosan, butanediol, and polyethylene glycol in the presence of caffeine as a synthesis catalyst. The obtained samples (with and without isosorbide nitrates) were characterized regarding the encapsulation and release rate (UV-Vis spectra), chemical composition (FTIR), thermal stability (thermal analysis), morphology changes (SEM and SANS), and in vivo irritation tests. These methods revealed no significant differences between the two sample structures. Multipopulational structures with sizes between 73 and 310 nm, with an increased tendency to form clusters and a high resistance to heat (up to 280°C), were obtained. This study presents an alternative administration of isosorbide derivatives based on a PU carrier with a high biocompatibility and a prolonged release.

Preparation of polypseudorotaxane composed of linear and cyclic polyethylene oxides and its application to solid polymer electrolyte

AbstractThe mixture of linear polyethylene glycol with molecular weight of 20,000 (l‐PEG20K) and cyclic polyethylene glycol with molecular weight of 1,000 (c‐PEG1K) was ultrasonicated in acetonitrile. After evaporating the solvent, the residue was analyzed by DSC to show a remarkable decrease of crystallization temperature. Such a large crystallization suppression was not observed when linear polyethylene glycol with molecular weight of 1,000 (l‐PEG1K) was added instead of c‐PEG1K. Further, the mixture of cyclic polyethylene glycols (c‐PEG6K and c‐PEG1K) did not exhibit a significant crystallization suppression. These experimental results indicated that formation of polypseudorotaxane through ultrasonication‐assisted ring penetration played an important role in the crystallization suppression. Ionic conductivities of the polypseudorotaxane‐based polymer electrolytes prepared from polyethylene oxide with molecular weight of 600,000 (PEO600K) and c‐PEG1K showed conductivity enhancement especially at low Li salt concentration.

Superlubrication obtained with mixtures of hydrated ions and polyethylene glycol solutions in the mixed and hydrodynamic lubrication regimes

HypothesisSuperlubricity is known to dramatically reduce frictional energy consumption and to improve service life of mechanical devices and biological systems. However, reduction of wear during the running-in period of friction pairs, especially under high contact pressures, still remains an unresolved issue affecting all machines. ExperimentsHere the lubrication, adsorption, and conformational properties of hydrated ions and polyethylene glycol (PEG) mixtures were evaluated at different mass fractions and concentrations of PEG and salts by ball-on-disc tribometer, ζ-potential, quartz crystal microbalance with dissipation (QCM-D), and dynamic light scatting (DLS) analyses. FindingsThese mixtures exhibited superlubricity between Si3N4 and sapphire surfaces in a wide range of concentrations and ions valency. Interestingly, a running-in phase shorter than 1 min and low wear rate of 1.85 μm3/(N·m) were observed at contact pressures up to 555 MPa, significantly higher to earlier findings. PEG chains retain random coils filling the bulk of the interfacial film without strongly adsorbing on the interfaces but significantly increasing the viscosity of lubricating film, thereby favoring hydrodynamic lubrication. Hydrated ions are strongly adsorbed on the negatively charged ceramic surfaces, ensuring a sustained hydration effect maintaining superlubricity. The outstanding lubrication characteristics of the PEG/ions mixtures were attributed to the synergistic action of hydration and hydrodynamic lubrication, which appears as a promising avenue for developing new green lubricants and has implications for industrial and biological applications.

Hot melt extruded zein for controlled delivery of diclofenac sodium: Effect of drug loading and medium composition

This study evaluates the potential use of zein as an excipient in hot-melt extrusion for controlled delivery of diclofenac sodium (DS). Mixtures of zein, polyethylene glycol and drug were hot melt extruded and cut into 2mm extrudates. Extrudates were characterised using differential scanning calorimetry, X-ray powder diffraction and scanning electron microscopy. The drug in the extrudates was found to be in the non-crystalline state, independent of the drug loading. Moreover, the drug release from extrudates was investigated. The release was directly dependent on the drug loading: a controlled and nearly zero-order release was obtained at the lowest drug loading (12.5% w/w), whereas almost immediate release was achieved at higher drug loadings, i.e. 25% and 37.5%. The release was inversely dependent on the ionic strength of the medium. The influence of digestive enzymes on drug release was also studied. Pancreatin, but not pepsin, was found to have a significant influence on the drug release as well as on the microstructure of zein extrudates. These data therefore support the potential use of zein as excipient in hot melt extrusion for controlled release purposes.

DISSOLUTION ENHANCEMENT AND FORMULATION OF FILM COATED TABLETS OF LORNOXICAM BY PHASE TRANSITION METHOD: IN VITRO AND IN VIVO EVALUATION

Objective: This study aimed to enhance the oral solubility and dissolution of poorly soluble lornoxicam by anti-solvent precipitation, and the manufacture of oral tablets by the phase transition method. 
 Methods: The solvent was mixture of polyethylene glycol 400 and absolute ethanol. Three stabilizers Inutec SP1, Pluronic F127, Sucrose ester S1670 at two concentrations and two matrix formers Mannitol, and Avicel PH102 were used to obtain 12 formulae. The formulae were characterized regarding their infrared spectroscopy (IR), differential scanning calorimetry (DSC), particle size (PS) measurement, drug content and dissolution. Further characterizations were done for the optimum formula by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Four tablet formulae were manufactured by phase transition method. The optimum tablets (T3) were evaluated through hardness, drug content, disintegration, dissolution, IR, and stability studies. Finally, (T3) was compared to conventional tablets in New Zealand rabbits using crossover design.
 Results: The dissolution rate for the prepared formulae was enhanced, from 3.44 to 5.96 folds. Statistical significance was obtained using one and two way ANOVA among formulae. The optimum tablet formula (T3) had hardness 5.637±1.57 kg, drug content 90.424±1.19%, disintegration time 341.5±9.62 s and the drug dissolved 72.107±0.0025%. Stability, after one month storage of the selected tablets at (25 °c/60% relative humidity), was satisfactory. The absorption extent of lornoxicam from (T3) compared to the conventional tablets was higher.
 Conclusion: Taken together, the obtained results confirmed successfully the potential of the promising formula (T3), over the conventional tablets of lornoxicam.

Liquid discharge plasma for fast biomass liquefaction at mild conditions: The effects of homogeneous catalysts

Non-thermal plasma exhibits unique advantages in biomass conversion for the sustainable production of higher-value energy carriers. Different homogeneous catalysts are usually required for plasma-enabled biomass liquefaction to achieve time-and energy-efficient conversions. However, the effects of such catalysts on the plasma-assisted liquefaction process and of the plasma on those catalysts have not been thoroughly studied. In this study, an electrical discharge plasma is employed to promote the direct liquefaction of sawdust in a mixture of polyethylene glycol 200 and glycerol. Three commonly used chemicals, sulfuric acid, nitric acid and sodium p-toluene sulfate, were selected as catalysts. The effects of the type of catalyst and concentration on the liquefaction yield were examined; further, the roles of the catalysts in the plasma liquefaction process have been discussed. The results showed that the liquefaction yield attains a value of 90% within 5 min when 1% sulfuric acid was employed as the catalyst. Compared with the other catalysts, sulfuric acid presents the highest efficiency for the liquefaction of sawdust. It was observed that hydrogen ions from the catalyst were primarily responsible for the significant thermal effects on the liquefaction system and the generation of large quantities of active species; these effects directly contributed to a higher efficacy of the plasma-enabled liquefaction process.

Preparation of Sn–58Bi solder powder by shearing liquids into complex particles

In the present work, Sn–58Bi solder powder that had a core–shell structure with particle diameter between 1.0 and 30.0 μm was prepared by shearing liquids into complex particles (SLICE). Molten Sn–58Bi alloys were dispersed into spherical microstructure coated with organic matter using high-speed mechanical agitation and dispersant, which was a mixture of paraffin and polyethylene glycol (PEG). Microstructural evolution of particles was investigated under variations in stirring rate (5000 rpm, 10,000 rpm, or 15,000 rpm) and cooling methods (air cooling, water cooling, or ice water cooling). The optimal Sn–58Bi solder powder that had a diameter ranging from 1.9 to 27.6 μm was obtained in a stirring time of 5 min, a stirring rate of 15,000 rpm, and a cooling method of ice water cooling. Such microparticles with favorable size are promisingly used in electronic industrial applications.

Differential adsorption of analyte and deuterated analogue onto the rotor seal of the injector in high-performance liquid chromatography/electrospray ionisation mass spectrometry.

Samples were injected onto the HPLC system via either a Valco C14W.1 internal sample injector or a Rheodyne 7125 injector, both with dissimilar Vespel rotor seals, and linked to a quadrupole time-of-flight (QTOF) mass spectrometer. Alternatively, samples were infused directly into the mass spectrometer via a syringe-driver. Electrospray ionisation in positive mode was used in both cases. Experiments demonstrated significant differential adsorption of the analyte (RAC inhibitor, NSC23766) and its tri-deuterated internal standard onto the Vespel rotor seal, with the latter seeming to be preferentially adsorbed. The deuterated analogue also showed lower electrospray sensitivity, as demonstrated by syringe infusion of a mixture of the compounds, compared with their separate infusion at the same concentration. This study has demonstrated the problem of differential adsorption onto HPLC Vespel rotor seals, and that the use of a stable-isotope-labelled analogue as internal standard does not guarantee the constancy of the analyte/internal response ratio in quantitative methods. The partial solution was to work at much higher concentration where adsorption, whilst still apparent, was relatively insignificant.

Development and characterization of eutectic phase change material for thermal energy storage system

The most efficient way to store thermal energy is the latent heat energy storage method because of its high energy storage density and almost constant freezing/melting temperature. The present study deals with the preparation of eutectic Phase change material (PCM) which is the mixture of myristic acid and Polyethylene glycol (PEG) of molecular weight 10000. The mixture was prepared in different weight fractions via facile incorporation method. The thermal and chemical properties of the eutectic mixture is characterized by DSC and FTIR technique. A mixture of 50% PEG 10000 and 50% myristic acid possess the maximum latent heat of 188.96 kJ/kg among all prepared samples and the final melting temperature achieved is 58.61 °C. The experimental results shows that the developed eutectic mixture possess good thermal energy storage capacity and can be a potential material for the thermal energy system applications.

Effect of polyethylene glycol mixtures as ointment base on the physicochemical properties of Lavsan atraumatic wound dressings

Objectives. Modern atraumatic wound dressings are based on polyethylene terephthalate, or Lavsan, which is shaped to form threads. The aim of the study was to determine the reasons for Lavsan woven nets’ hardening and becoming more trauma-prone during storage, and to find ways of eliminating these effects.Methods. We used differential scanning calorimetry, performed on a NETZSCH DSС 204 F1 Phoenix device, in a dynamic mode with a temperature range from 20 to 300 °C in argon flow to determine phase states, glass transition temperatures, and melting temperatures of Lavsan fibers (including those treated with polyethylene glycol mixtures). We performed rheoviscometry studies on a Brookfield DV2TLV rotational viscometer, with a SC4-16 thermostatic control unit, at the following temperatures: 25, 36.6, 40, 45, 50, and 55 °C, with shear rates ranging from 120 to 200 s–1 to determine dynamic viscosity and investigate the mixing characteristics of polyethylene glycols with different molecular weights.Results. We have established that samples of Lavsan woven nets, stored long-term in laboratory conditions (up to 2, 3, and 16 years), are in the crystalline state with a high degree of crystallinity. Upon heating these nets to 300 °C, it is possible to reduce the degree of crystallinity by 19–32%, but it does not completely eliminate the effect. Polyethylene glycols and their mixtures which exhibit non-Newtonian flow behavior and are used as an ointment base, have a significant effect on Lavsan’s crystallinity. We have determined that the optimal ratio of polyethylene glycols for the modification of Lavsan nets is PEG-400:PEG-1500 = 80:20 wt %. Upon storing Lavsan woven nets in this mixture at room temperature, the Lavsan’s crystallinity is greatly reduced, and upon heating the system, the crystallinity practically disappears.Conclusions. The effect of polyethylene glycol mixtures (the base for therapeutic ointments) with various molecular weights on the phase organization of Lavsan has been evaluated. As a result of this study, we can offer a new approach to reduce the injuring effect of synthetic (Lavsan) bases of atraumatic wound dressings.

Effect of sodium citrate/polyethylene glycol on plasticization and retrogradation of maize starch

Maize starch was plasticized by mixtures of sodium citrate and polyethylene glycol 200 (PEG200) at varied weight ratios (citric acid/PEG200, 25/0, 20/5, 15/10, 10/15, 5/20 and 0/25). The structure and pasting, aging, moisture absorption and thermal properties of the plasticized starches were studied by means of Fourier transformed infrared, X-ray diffraction, rapid viscosity analysis, tension test and thermogravimetric analysis. Comparing with single plasticizer, co-plasticizers with appropriate proportions are more effective in hindering the retrogradation of starch paste and film. The results also showed that the mechanical property and humidity sensitivity of the starch film worsen after the introduction of PEG200 compared with sodium citrate plasticized starch, but the thermal stability and anti-aging property increase. This is consistent with the association ability of plasticizers with starch observed from FTIR. In addition to the simple additive effect of components on some properties, special formulations also show some synergistic effects, such as the co-plasticizer of 20% citric acid and 5% PEG200 has a better comprehensive property for plasticizing the maize starch bulk than sodium citrate or PEG200 alone. The mixture of sodium citrate and PEG200 can be used as a candidate plasticizer for preparing thermoplastic starch for food and packaging industries.

The effect of citric acid and sodium bicarbonate concentration on the quality of effervescent of red ginger extract

The effervescent product of red ginger extract was made from a mixture of red ginger extract, citric acid, sodium bicarbonate, dextrose, mannitol, sucralose and polyethylene glycol. This study used a single factor randomized complete design method with the ratio of different concentrations of citric acid and sodium bicarbonate (50:50, 51:49, 52:48, 53:47, 55:45) in three replication. Analysis of Variance (ANOVA) was used to see the effect of each treatment, if there was an effect of each treatment then continued with DMRT (Duncan Multiple Range Test) to see which levels produced differences in quality. The results showed that the addition of different concentrations of citric acid and sodium bicarbonate had significant effect (sig <α=0.01) on the value of soluble and effervescent pH of red ginger extract and significantly affected the level of color preference, taste and effervescent solubility of red ginger extract. The best effervescent product of red ginger extract was selected based on the hedonic test with the ratio of citric acid and sodium bicarbonate 52:48 with the following quality test results: 0.00% ethanol residue; levels of active red ginger 0.65%; and the level of effervescent red ginger extract 0.52%.

Evaluation of Lipophilic Properties of Thermoplastic Granule in Formulation of Sustained Release Matrix in Solid Dosage Forms

This study was aimed at developing a new, technically simple method for the preparation of a once-daily sustained release matrix formulations, which would enable reproducible release of the active ingredient. Thermoplastic granulation is a new technique in pharmaceutical formulation. Coated particles of an active pharmaceutical ingredient (API) in sustained release matrix are prepared by thermoplastic granulation technique via heating (50 – 75°C) in fluid-bed dryer (FBD) granulator. The FBD creates ideal conditions for the most intense heat and mass transfer by spraying melted liquids onto the granular API. A variety of innovative processes such as granulation, agglomeration, coating and microencapsulation can be realized. Melted mixture of cetyl alcohol, glyceryl monostearate, and polyethylene glycol 4000 (PEG 4000) was used for fluid-bed coating. The present article deals with assessing the influence of rheological properties and hydrophile-lipophile balance (HLB) parameter of thermoplastic granules on the mechanism of drug delivery from sustained release matrix in solid dosage forms. The drug release kinetics model is affected by rheology, HLB of cetyl alcohol, and physicochemical properties of API granules.

Physicochemical investigations of polyethylene glycols with N, N dimethylacetamide

The densitiesρ and ultrasonic speeds u for the binary mixture of polyethylene glycol (PEG 200) and poly ethylene glycol 400 (PEG 400) with N, N dimethylacetamide (DMA) are measured over the entire mole fraction range and at temperatures 303.15, 313.15, and 323.15 K. From the experimental data, and excess molar volume, VmE, excess ultrasonic speed uE, excess isentropic compressibility κsE, Excess intermolecular free length LfE, excess acoustic impedance ZE and excess molar isentropic compressibility Ks,mE are evaluated. The partial molar properties and their excess properties are also determined. The solute-solvent interactions are also analyzed using FTIR spectra, recorded at the room temperature.