Effect Of Polyethylene Glycol Concentration Research Articles

Fabrication and Photothermal Phase Change Properties of Polyethylene Glycol/Melamine Sponge/Polyurethane/Zirconium Carbide Composites

ABSTRACT Solar energy is a green, sustainable, and abundant renewable resource. Adding photothermal conversion materials to phase change materials can increase the photothermal conversion efficiency and heat storage capacity of phase change materials. In this work, polyethylene glycol (PEG) was used as phase change material, zirconium carbide was used as photothermal conversion material, melamine sponge was used as the carrier, and polyurethane was used as coating to prepare phase change photothermal composites. The effects of PEG concentration and zirconium carbide concentration on the thermal properties of composite phase change materials were discussed. The results showed that when the PEG concentration was 80% and the zirconium carbide concentration was 5%, the composites showed better comprehensive properties with less leakage and high enthalpy (186.5J/g). Surface temperature of the composites could rise to 54°C in 300 s under infrared light, and the enthalpy value of phase change and the photothermal conversion capacity could maintain 97% after 50 cycles of testing. The composites could be used in various fields such as car seats, cushions, and mattresses.

The Effect of polyethylene glycol concentration on some varieties of kenaf (Hibiscus cannabinus L.) in enhancing the germination viability

The purpose of this study was to see the interaction between the concentration of Polyethylene Glycol and various varieties of kenaf (Hibiscus cannabinus L.) On plant germination. This study used a completely randomized factorial design with 3 replications. The factors used for the study were varieties of kenaf (Karang Proso 6, Karang Proso 9 and Karang Proso 15) and the concentration of Polyethylene Glycol (0, 3, 5, and 7 ppm). Data were analyzed using analysis of variance (F test) using least significant difference (LSD) test of 5%. There was an interaction between the concentration of Polyethylene Glycol and kenaf varieties on germination power. Karang Proso 9 variety was consistent with several concentrations of Polyethylene Glycol which had higher germination compared to other varieties. Polyethylene Glycol concentration did not affect hypocotyl length, seed germination uniformity, dry weight of the varieties of Karang Proso 6, Karang Proso 9 and Karang Proso 15.

Development of cellulose acetate/metal-organic framework derived porous carbon adsorptive membrane for dye removal applications

In this work, metal-organic framework derived porous carbon (MOFDPC) nanoparticles (NPs) were synthesized and incorporated into cellulose acetate (CA) polymeric matrix to prepare biodegradable CA/MOFDPC adsorptive membranes via phase inversion method. Polyethylene glycol (PEG) was used as pore former agent. Performance of the prepared membranes was evaluated in methylene blue (MB) removal from aqueous solution via continuous adsorption experiments. The physicochemical properties of the fabricated membranes were characterized by contact angle measurement, SEM, FTIR, AFM, TGA and tensile strength analysis. At first, the effects of PEG concentration and MOFDPC NPs loading were investigated. It was found that the best performance is obtained for the prepared membrane containing 15 wt% PEG and 2 wt% of MOFDPC NPs as the optimal adsorptive membrane. Then, the effects of solution pH, initial MB concentration and operating pressure on the MB removal capability of the prepared optimal adsorptive membrane were investigated. Reusability of the optimal adsorptive membrane was studied via subsequent adsorption/desorption cycles. Its long-term behavior was also studied. The obtained results showed that the prepared biodegradable CA/MOFDPC adsorptive membrane with MB removal percentage of 98.2% and permeate flux of 76.03 LMH and excellent reusability and long-term behavior can be potentially utilized for wastewater treatment applications especially MB removal.

Effect of Polyethylene Glycol Concentration on the Formation of Aluminium-Doped Zinc Oxide Nanorods

Aluminium (Al) - doped zinc oxide (ZnO) nanorods with different weight percent (wt%) of polyethylene glycol (PEG) has been deposited on glass substrate. The concentrations of PEG have been varied from 0 wt %, 15 wt % and 30 wt %. The percentage weight of the PEG is the ratio between PEG mass to the hexamethyltetramine (HMT) and zinc nitrate hexahydrate (Zn (NO3).6H2O) mass. The structural properties of the samples have been characterized using field emission scanning electron microscopy (FESEM) and x-ray diffraction (XRD) and electrical properties has been characterized using current voltage (I-V) measurement. The analyses showed that PEG addition have reduced the crystallinity and conductivity of the samples.

Statistical analysis of the effects of polyethylene glycol concentration and molecular weight on the sedimentation and resuspendability behavior of model aqueous dispersions

This work investigates the flocculation effect of polyethylene glycol (PEG) on typical aqueous dispersions, such as O/W emulsions and solid/liquid suspensions. Hereby, sunflower oil and flubendazole were selected as model ingredients, whereas microfluidization at variable driving air pressure was used to enable particle size distribution variations for both systems. The molecular weight of PEG varied from 2000 to 12,000g/mol while its concentration ranged from 50 to 100mg/ml. Statistical analysis revealed that both PEG concentration and molecular weight showed a flocculation enhancing effect. Hereby the inhibiting effect of particle size toward the formation of voluminous and easily resuspendable sediment could at least partially be overcome by selecting appropriate PEG characteristics.

A potential for overestimating the absolute magnitudes of second virial coefficients by small-angle X-ray scattering

Theoretical consideration is given to the effect of cosolutes (including buffer and electrolyte components) on the determination of second virial coefficients for proteins by small-angle X-ray scattering (SAXS)—a factor overlooked in current analyses in terms of expressions for a two-component system. A potential deficiency of existing practices is illustrated by reassessment of published results on the effect of polyethylene glycol concentration on the second virial coefficient for urate oxidase. This error reflects the substitution of I(0,c3,0), the scattering intensity in the limit of zero scattering angle and solute concentration, for I(0,0,0), the corresponding parameter in the limit of zero cosolute concentration (c3) as well. Published static light scattering results on the dependence of the apparent molecular weight of ovalbumin on buffer concentration are extrapolated to zero concentration to obtain the true value (M2) and thereby establish the feasibility of obtaining the analogous SAXS parameter, I(0,0,0), experimentally.

Role of additives in electroless copper plating using hypophosphite as reducing agent

In electroless copper plating baths using hypophosphite as the reducing agent, nickel ions was used to catalyze hypophosphite oxidation. However, the color of the copper deposits was dark or brown and the electrical resistivity was much higher than that obtained from formaldehyde baths. Polyethylene glycol (PEG) and K4Fe(CN)6 were used to improve the microstructure and properties of copper deposits obtained from electroless copper plating bath using hypophosphite as the reducing agent. The effects of PEG concentration on the deposition rate, the microstructure, morphology and electrical resistivity of the copper deposits, and the electrochemical reactions of hypophosphite (oxidation) and cupric ion (reduction) were investigated. The traces of hydrogen escaping from the deposits surface disappeared and the color of the copper deposits changed from dark-brown to dark red when the PEG concentration was 1.67×10−5M or more. The deposition rate increased and the electrical resistivity of the copper deposits decreased slightly with the addition of PEG to the plating solution. The electrical resistivity of copper deposits decreased to 2.85μΩ cm with 1.67×10−5M PEG and 4.70×10−6M K4Fe(CN)6 in the bath. Larger grain size and higher (220) plane orientation were obtained with the increase of PEG concentration in the bath. The electrochemical current–voltage results showed that PEG accelerated the catalytic oxidation of hypophosphite at active nickel sites and had little effect on the reduction reaction of cupric ions on the deposit surface by adsorption on the electrode.

Characteristics of polycarbonate membranes with polyethylene glycol prepared via dry/wet-phase inversion methods

The preparation and development of mem-branes for gas separation processes was per-formed during the last decade. It is important thatthe modifications in the physical and chemicalstructures of polymeric membranes have beenmade to achieve better separation characteristics.Membrane material is a key factor for the success-ful separation of mixture. The chemical nature,molecular structure, physical and mechanicalproperties and morphology of polymers andcopolymers affect the performance and selectivityof resulting membrane. Identifying new mem-brane materials and morphologies for industrialseparations has become an important researchobjective [1]. The membrane structure may deter-mine the separation mechanism and hence theapplication; thus, membra ne morphology is one ofthe most important parameters that affects themembrane performance. Polymer materials usedfor the membrane are polycarbonate (PC) [2],polypropylene (PP) [3], polyamide [4], polysul-fone (PSF) [5], block copolymers [6,7], and so onand preparation methods such as dry and wetinversion [8,9], plasma treatment [10], inversionin supercritical fluids [11], etc., were selected forthe porous membrane. In the work, PC membranes with polyethyleneglycol (PEG) that have the different molecularweights could be prepared via dry-phase and wet-phase inversion methods. These methods wereused for casting films from solutions with varyingconcentrations. Chloroform and methylene chlo-ride were used to determine the effect of the cast-ing solvent. The casting solutions were obtainedby dissolving PC and PEG in different composi-tions (3–15 w/v%). PEG concentration wasranged from 0 to 20 wt.% to investigate the effectof PEG concentration on membrane porosity.Effects of PEG concentration and molecularweight, membrane thickness and temperature onthe membranes were investigated. Permeationmeasurements are done with pure gases such asN

Extended release of a novel antidepressant, venlafaxine, based on anionic polyamidoamine dendrimers and poly(ethylene glycol)‐containing semi‐interpenetrating networks

The multiple daily administration of venlafaxine, a novel third-generation antidepressant, was reduced based on polyamidoamine and polyethylene glycol (PEG)-containing semi-interpenetrating network (IPN), respectively. Venlafaxine was covalently linked to water-soluble G2.5 anionic polyamidoamine dendrimer via a hydrolyzable ester bond. Semi-IPN hydrogels were prepared by crosslinking acrylamide in the presence of PEG, and venlafaxine with predetermined amounts was loaded in situ. Dendrimer-venlafaxine conjugate and semi-IPNs were characterized by proton nuclear magnetic resonance and Fourier transform infrared, respectively. The effect of PEG concentration and molecular weight was studied and discussed for an optimal controlled release.

Observation of liquid-liquid phase separation for eye lens gammaS-crystallin.

gammaS-crystallin (gammaS) is an important human and bovine eye lens protein involved in maintaining the transparency of the eye. By adding small amounts of polyethylene glycol (PEG) to the binary aqueous bovine gammaS solutions, we have observed liquid-liquid phase separation (LLPS) at -8 degrees C and revealed that, in the binary gammaS-water system, this phase transition would occur at -28 degrees C. We have measured both the effect of PEG concentration on the LLPS temperature and proteinPEG partitioning between the two liquid coexisting phases. We use our measurements of proteinPEG partitioning to determine the nature and the magnitude of the gammaS-PEG interactions and to quantitatively assess the effectiveness of PEG as a crystallizing agent for gammaS. We use our measurements of LLPS temperature as a function of protein and PEG concentration to successfully determine the location of the critical point for the binary gammaS-water system. This phase transition cannot be observed in the absence of PEG because it is inaccessible due to the freezing of the system. Our findings indicate that the effective interactions between gammaS molecules in the binary gammaS-water system are attractive. We compare the magnitude of the attraction found for gammaS with the results obtained for the other gamma-crystallins for which the critical temperature is located above the freezing point of the system. This work suggests that PEG can be used to reveal the existence of LLPS for a much wider range of binary protein-water systems than known previously.

Plasmid transformation of Mycoplasma mycoides subspecies mycoides is promoted by high concentrations of polyethylene glycol

The recent isolation and characterization of two plasmids from Mycoplasma mycoides subspecies mycoides has opened up new possibilities for studying mycoplasmal genetics. In order to facilitate the development of a genetic system in M. mycoides subsp. mycoides, parameters of polyethylene glycol (PEG)-mediated transformation were examined, as existing protocols prove very inefficient in this organism. The effects of PEG concentration, DNA concentration, presence of Ca 2+ ions, and choice of buffers on the transformation of the Tn 916-containing plasmid pAM120 into M. mycoides subsp. mycoides were examined. The stability of Tn 916 in the M. mycoides subsp. mycoides chromosome was also evaluated. The optimal PEG concentration (53–62% ( w v )) in the transformation mixture was substantially higher than the PEG concentration reported to be optimal for transformation of other mycoplasmas (36% ( w v )). The PEG concentrations used here were also higher than the concentration used to promote transformation or fusion of gram-positive bacterial protoplasts. A necessity for the presence of Ca 2+ ions for optimal transformation was shown, as was the possible involvement of cell culture growth stage. Our results demonstrate the need for expanding current transformation techniques for mycoplasmas. Studies also indicate that once Tn 916 inserts into the M. mycoides subsp. mycoides chromosome, it can transpose to other sites at a relatively high frequency.

Polyvinyl alcohol and polyethylene glycol as protectants against fluid-mechanical injury of freely-suspended animal cells (CRL 8018)

Two identical bioreactors run in parallel were used to examine the phenomenological characteristics of two additives, polyethylene glycol (PEG) and polyvinyl alcohol (PVA), used as protectants against fluid-mechanical cell damage. Cell-protecting ability was evaluated by comparing apparent cell growth rates of freely suspended CRL-8018 hybridoma cells cultured in serum-free medium under surface aerated conditions whereby cell damage is due to bubble entrainment and breakup. PEG of various molecular weights was used to determine whether the size of the polymer has significant effects on PEG's cell-protecting capabilities. All the PEG's with molecular weights larger than 1400 showed similar protective effects. The effect of PEG concentration was then evaluated and results showed that concentrations greater than 0.05% w/v did not significantly improve the cell-protecting properties. Direct comparisons made between the PVA, PEG, and pluronic F68 as cell protectants showed that PEG protected cells better than F68 and that PVA provided even better protection than PEG. The mechanism of protection, fluid-mechanical or biological in nature, was examined by growing the cells in additive from the beginning of the experiment (long-term exposure), or adding the additive after the cells had been agitated at rates detrimental to the cells (short-term exposure). In agreement with results reported previously on PEG and F68, fast-acting protection was seen. This implies a fluid-mechanical rather than a biological protection mechanism. In an attempt to correlate interfacial properties of the resulting media with shear protection, interfacial tension and viscosity measurements of all the media were made. On the basis of these measurements, we find no definitive correlations for evaluating these additives' cell-protecting capabilities.