Ratio Of Polyethylene Glycol Research Articles

페길화에 의한 재조합 산화환원 조절단백-1의 환원력 유지 최적화

PEGylation of recombinant proteins enhances their bioavailability by improving stability, solubility, and biological activity. This study aimed to optimize conditions for PEGylating apurinic/apyrimidinic endonuclease 1/redox effector factor-1 (APE1/Ref-1) to preserve its reducing activity and ensure it remains non-immunogenic in vivo. The PEGylation reaction of recombinant APE1/Ref-1 showed a progressive pattern dependent on the molar ratio with methoxy polyethylene glycol (PEG)-succinimidyl-glutarate. Optimal PEGylation was achieved with a 30 molar ratio of PEG, modifying 29 lysine residues of recombinant APE1/Ref-1. Activity analysis demonstrated that PEGylated APE1/Ref-1 retained reducing activity for over 4 weeks under refrigerated conditions, comparable to its pre-preservation state. To evaluate the immunogenicity of PEGylated APE1/Ref-1 for in vivo applications, an enzyme linked immunosorbent assay confirmed that PEGylation did not alter its antigenicity. PEGylation is a critical strategy for developing biopharmaceuticals and is expected to be highly beneficial for in vivo applications.

Thermal energy storage performance of liquid polyethylene glycol in core–shell polycarbonate and reduced graphene oxide fibers

Thermal energy storage is a promising, sustainable solution for challenging energy management issues. We deploy the fabrication of the reduced graphene oxide (rGO)–polycarbonate (PC) as shell and polyethylene glycol (PEG) as core to obtain hydrophobic phase change electrospun core–shell fiber system for low-temperature thermal management application. The encapsulation ratio of PEG is controlled by controlling the core flow rate, and ~ 93% heat energy storage efficacy is apparent for 1.5 mlh−1 of core flow rate. Moreover, the prepared fiber possesses maximum latent melting and freezing enthalpy of 30.1 ± 3.7 and 25.6 ± 4.0 Jg−1, respectively. The transient dynamic temperature vs. time curve of the rGO-loaded phase change fiber demonstrates the delay of fiber surface temperature change compared to pristine fiber. We indeed show that the tunable heat transfer and thermal energy storage efficacy of phase change fiber is achieved via controlled liquid PEG delivery and the addition of rGO in shell architecture. Notably, the effectiveness of unique phase change material (PCM)–based core–shell fibers is concluded from advanced scanning thermal microscopy (SThM) and self-thermoregulation tests.

Nanostructure and interfacial mechanical properties of PEG/cellulose nanocomposites studied with molecular dynamics

Our starting hypothesis is that Polyethylene glycol (PEG) can be utilized to mix with the biopolymers for consolidating fiber-reinforced composites without deteriorating their hygro-mechanical properties. The effect of PEG on the shear strength during pull-out of crystalline cellulose (CC) fiber out of an amorphous cellulose matrix is simulated with molecular dynamics. The interfacial shear stress shows a stick-slip behavior and is weakened with increasing moisture content. Shear strength increases at low moisture content, manifesting a slight strengthening of interfacial mechanical property due to cohesive forces exerted by the water molecules. At higher moisture content, shear strength is reduced due to breakage of the hydrogen bonds between CC and matrix by water molecules. When adding PEG, amorphous cellulose around the crystalline fiber is replaced by PEG, forming a mixture with amorphous cellulose. It is found that PEG-treated CC-AC composite maintains its shear strength and the presence of PEG does not deteriorate the dependence of the shear strength on moisture content. A shear strength model based on the number of hydrogen bonds between the fiber and the matrix is developed, which validates our initial hypothesis by unraveling the fundamental mechanisms at play. The model reveals that, although the shear strength per hydrogen bond between the fiber and PEG is lower than the shear strength per hydrogen bond between the fiber and amorphous cellulose, the final shear strength is partly compensated by an increase in the total number of hydrogen bonds with increasing PEG ratio. Since PEG reduces the moisture content in the composite at low relative humidity, PEG treated wood in museum conditions will show enhanced shear strength. The framework is a basis for further investigation of realistic archaeological wood with PEG-treatment.

The Emerging Role of Polyethylene Glycol-Water (PEG-H2O) as the Benign Mixed Solvent System in Organic Synthesis

Abstract: Polyethylene glycol (PEG) has become a popular solvent and green catalyst for a variety of chemical reactions. It is a stable and biodegradable polymeric catalyst used in organic synthesis because it may be recycled numerous times without significantly losing its catalytic activity. Recently, the use of PEG-H2O mixed solvent systems in organic synthesis has gained popularity. This article presents an overview of PEG-H2O solvent system-mediated organic reactions, with a main focus on the importance of the solvent system. The study also focuses on recent developments in the PEG-H2O solvent system-mediated synthesis of a number of heterocy-clic compounds. Important characteristics of these PEG-H2O solvent systems include high atom economies, gentle reaction conditions, faster reaction rates, readily isolated side products and high yields. Results from various reactions showed that the choice of proper ratio of PEG: H2O solvent system plays a key role in product yields.

Echinacea purpurea L. Kallus Kültürlerinde Karbon Kaynağı, Nitrojen ve PEG'in Kafeik Asit Türevlerinin Üretimine Etkisi

This study aimed to determine the effects of polyethylene glycol (PEG) as an abiotic elicitor and nutritional factors (different ammonium/nitrate ratios, carbon source and amount) in the culture medium on the production of Caffeic Acid Derivatives (CADs) in callus cultures of Echinacea purpurea L. Petiole and root explants were cultured on MS medium modified in terms of different types (sucrose and maltose) and amounts (sucrose 15, 45, 60 g l-1, and maltose 15, 30, 45, 60 g l-1) of carbon source, different concentrations (5, 10, 15 g l-1) of PEG and ammonium nitrate ratios (0:35, 5:25, 15:15, 35:0 mM). The amounts of CADs in the callus obtained at the end of the 10-week culture period were analysed. In both explant types, the highest amount of CADs were obtained from the medium containing 15 g l-1 sucrose and 15 or 30 g l-1 maltose applications, while the highest amount of CADs was obtained in the medium containing 0:35 mM ammonium/nitrate in nitrogen applications. While the highest amount of CADs in root explant was obtained from the medium containing 10 g l-1 PEG applications, CADs content could not be obtained in petiole explant. As a result, the highest amounts of caftaric, chlorogenic, caffeic, and chicoric acids (respectively, 9.38, 0.71, 0.29, and 34.77 mg g-1) were determined at callus obtained from root explant cultured on MS medium containing 30 g l-1 sucrose and 0:35 mM ammonium/nitrate. In conclusion, optimization of culture conditions and different elicitor applications were made to increase secondary metabolite content in E. purpurea L. under in vitro conditions and the results obtained were presented comparatively.

Influence of PEGylation on WS2 Nanosheets and Its Application in Photothermal Therapy.

Photothermal therapy (PTT) is an alternative cancer therapy with minimal side effects and higher efficiency and selectivity. In this study, WS2 nanosheets were developed by ultrasonic exfoliation with different ratios of polyethylene glycol (PEG), and their effects on physicochemical properties were studied. The utilization of PEG during sonication significantly influenced the size and thickness of the resulting WS2 nanosheet layers, which was confirmed through scanning electron microscopy, atomic force microscopy, and dynamic light scattering analyses. PEG functionalization also improved the dispersibility of WS2 in aqueous solution by making its surface hydrophilic, which resulted in better biocompatibility. The intrinsic near-infrared absorbance of the nanosheets positions them as valuable agents for PTT. The study further explores the efficacy of these nanosheets as photothermal agents in the ablation of MDAMB-231 breast cancer cells. Although the use of PEG to demonstrate exfoliation and biocompatibility for WS2 has been reported previously, the effect of PEGylation on various physicochemical properties has not been studied in-depth until now. This study paves the way for the use of highly versatile PEG across a range of 2D material systems.

Production of Ultrafine PVDF Nanofiber-/Nanonet-Based Air Filters via the Electroblowing Technique by Employing PEG as a Pore-Forming Agent.

Particles with diameters smaller than 2.5 μm (PM2.5) can penetrate the respiratory system and have negative impacts on human health. Filter media with a porous surface and nanofiber/nanonet structure demonstrate superior filtration performance compared to traditional nano- and microfiber-based filters. In this study, nanostructured filters were produced using the electroblowing method from solutions containing different ratios of poly(vinylidene fluoride) (PVDF) and polyethylene glycol (PEG) polymers for the first time. By increasing the water-soluble PEG ratio in PVDF/PEG blend nanofibers and employing a water bath treatment to the produced mat afterward, a more porous fibrous structure was obtained with a lower average fiber diameter. Notably, the removal of PEG from the PVDF/PEG (3-7) sample, which had the highest PEG content, exhibited clustered nanofiber-/nanonet-like structures with average diameters of 170 and 50 nm at the points where the fibers intersect. Although this process resulted in a slight decrease in the filtration efficiency (-1.3%), the significant reduction observed in pressure drop led to a 3.2% increase in the quality factor (QF). Additionally, by exploiting the polarizability of PVDF under an electric field, the filtration efficiency of the nanostructured PVDF filters enhanced with a ratio of 3.6% after corona discharge treatment leading to a 60% improvement in the QF. As a result, the PVDF/PEG (3-7) sample presented an impressive filtration efficiency of 99.57%, a pressure drop (ΔP) of 158 Pa, and a QF of 0.0345 Pa-1.

Mechanical Properties and Liquid Absorption of Calcium Phosphate Composite Cements.

Calcium phosphate cements present increased biocompatibility due to their chemical composition being similar to that of the hydroxyapatite in the hard tissues of the living body. It has certain limitations due to its poor mechanical properties, such as low tensile strength and increased brittleness. Thus, the optimal way to improve properties is through the design of novel composite cements. The purpose was fulfilled using a 25% hydroxyethyl methacrylate (HEMA) mixed with 3% urethane dimethacrzlate (UDMA) base matrix with various ratios of polyethylene glycol (PEG 400) and polycaprolactone (PCL). Mineral filler is based on tricalcium phosphate (TCP) with different chitosan ratio used as bio-response enhancer additive. Four mixtures were prepared: S0-unfilled polymer matrix; S1 with 50% TCP filler; S2 with 50% chitosan + TCP filler; and S3 with 17.5% chitosan + TCP mixed with 17.5% nano hydroxyapatite (HA). The mechanical properties testing revealed that the best compressive strength was obtained by S2, followed by S3, and the worst value was obtained for the unfilled matrix. The same tendency was observed for tensile and flexural strength. These results show that the novel filler system increases the mechanical resistance of the TCP composite cements. Liquid exposure investigation reveals a relative constant solubility of the used filler systems during 21 days of exposure: the most soluble fillers being S3 and S2 revealing that the additivated TCP is more soluble than without additives ones. Thus, the filler embedding mode into the polymer matrix plays a key role in the liquid absorption. It was observed that additive filler enhances the hydrophobicity of UDMA monomer, with the matrix resulting in the lowest liquid absorption values, while the non-additivated samples are more absorbent due to the prevalence of hydrolytic aliphatic groups within PEG 400. The higher liquid absorption was obtained on the first day of immersion, and it progressively decreased with exposure time due to the relative swelling of the surface microstructural features. The obtained results are confirmed by the microstructural changes monitored by SEM microscopy. S3 and S2 present a very uniform and compact filler distribution, while S1 presents local clustering of the TCP powder at the contact with the polymer matrix. The liquid exposure revealed significant pore formation in S0 and S1 samples, while S3 and S2 proved to be more resistant against superficial erosion, proving the best resistance against liquid penetration.

Heterogenous electro-Fenton degradation of sulfamethoxazole on a polyethylene glycol-coated magnetite nanoparticles catalyst

We report the preparation and application of poly (ethylene) glycol (PEG) coated magnetite nanoparticles (MNPs) catalyst for the heterogeneous electro-Fenton (HEF) degradation of sulfamethoxazole in real wastewater PEG-coated MNPs of four MNP:PEG ratios were synthesised using the co-precipitation method. The synthesised MNP were characterised using FTIR, XRD, EDX, TEM, and CHN elemental analysis. It was observed that the coating of MNP with PEG influences the nanoparticle size, agglomeration tendencies and catalytic efficiency of MNPs properties in the HEF degradation process. A 1:1 optimal MNP:PEG catalyst yielded 91% sulfamethoxazole degradation and 48% total organic carbon removal in 60 min, which is an improvement of 11% over degradation with the uncoated MNP. The PEG-coated MNP showed higher stability in 10 consecutive reaction cycles, reduced leaching, and improved performance at a lower dosage and broader pH range than the uncoated MNPs. These results show that coating MNP with PEG enhances HEF catalytic performance in the degradation of sulfamethoxazole in wastewater.

Efficient transfected liposomes co-loaded with pNrf2 and pirfenidone improves safe delivery for enhanced pulmonary fibrosis reversion

Pulmonary fibrosis (PF) is an interstitial lung disease with complex pathological mechanism, and there is currently a lack of therapeutics that can heal it completely. Using gene therapy with drugs provides promising therapeutic strategies for synergistically reversing PF. However, improving the intracellular accumulation and transfection efficiency of therapeutic nucleic acids is still a critical issue that urgently needs to be addressed. Herein, we developed lipid nanoparticles (PEDPs) with high transfection efficiency coloaded with pDNA of nuclear factor erythroid 2-related factor 2 (pNrf2) and pirfenidone (PFD) for PF therapy. PEDPs can penetrate biological barriers, accumulate at the target, and exert therapeutic effects, eventually alleviating the oxidative stress imbalance in type II alveolar epithelial cells (AECs II) and inhibiting myofibroblast overactivation through the synergistic effects of Nrf2 combined with PFD, thus reversing PF. In addition, we systematically engineered various liposomes (LNPs), demonstrated that reducing the polyethylene glycol (PEG) proportion could significantly improve the uptake and transfection efficiency of the LNPs, and proposed a possible mechanism for this influence. This study clearly reveals that controlling the composition ratio of PEG in PEDPs can efficiently deliver therapeutics into AECs II, improve pNrf2 transfection, and synergize with PFD in a prospective strategy to reverse PF.

Shrinkage Volume, Compressive Strength, and Surface Roughness Y-TTRIA Stabilized Tetragonal Zirconia Polycrystal (Y-TZP) Using Binders Variation PVA:PEG as an Alternative Dental Implants Materials.

Yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) is one of the materials that can be used as an alternative material for dental implants because of its good mechanical, biocompatible, and aesthetic properties. The binder used for ceramic processing to help bond is polyvinyl alcohol (PVA), which can increase the density of the ceramic material, and polyethylene glycol (PEG), which is used as a plasticizer for PVA, so it is pretty soft when pressed. The sample was divided into five groups for volume shrinkage and compressive strength examination consisting of K1 (PVA 100%), K2 (PEG 100%), P1 (PVA:PEG 95:5), P2 (PVA:PEG 90:10), and P3 (PVA:PEG 85:15) and four groups on the surface roughness test, namely, K (PVA:PEG 1%), P1 (PVA:PEG 2%), P2 (PVA:PEG 3%), and P3 (PVA:PEG 4%). PVA:PEG binder with various concentrations was mixed with Y-TZP. The mixture was pressed using a uniaxial pressing method and continued by sintering at 1200°C for 4 hours. Least significant difference (LSD) test result showed that there was a significant difference in the compressive strength value and shrinkage volume between groups K1 and K2 and P3, and groups K2 with P1, P2, and P3. Post hoc LSD surface roughness test showed a significant difference between groups K with P2 and P3 and P1 and P3 (p < 0.05). There were no significant differences (p > 0.05) between K with P1 and P2 with P3. The Y-TZP group with the PVA binder mixture had the highest compressive strength, while the highest volume shrinkage was found in the PEG group. The next highest compressive strength and volume shrinkage values were found in the PVA:PEG group with a ratio of 95:5, 102.44 MPa, and 12.5%. The best PVA:PEG ratio of 95:5 is used to make surface roughness measurement samples. The best results showed that mixing Y-TZP with 4% PVA:PEG binder had the highest surface roughness compared to other PVA:PEG binders, namely 1.3450 μm. From this study, it can be concluded that the best PVA:PEG percentage ratio to produce volume shrinkage and compressive strength is 95:5. The higher the concentration of PVA:PEG (95:5) binder mixed with Y-TZP, the higher the porosity will be.

Carbon nanotubes as a nitric oxide nano-reservoir improved the controlled release profile in 3D printed biodegradable vascular grafts

Small diameter vascular grafts (SDVGs) are associated with a high failure rate due to poor endothelialization. The incorporation of a nitric oxide (NO) releasing system improves biocompatibility by using the NO effect to promote endothelial cell (EC) migration and proliferation while preventing bacterial infection. To circumvent the instability of NO donors and to prolong NO releasing, S-nitroso-N-acetyl-d-penicillamine (SNAP) as a NO donor was loaded in multi-walled carbon nanotubes (MWCNTs). Successful loading was confirmed with a maximum SNAP amount of ~ 5% (w/w) by TEM, CHNS analysis and FTIR spectra. SDVGs were 3D printed from polycaprolactone (PCL) and coated with a 1:1 ratio of polyethylene glycol and PCL dopped with different concentrations of SNAP-loaded matrix and combinations of MWCNTs-OH. Coating with 10% (w/w) SNAP-matrix-10% (w/w) SNAP-MWCNT-OH showed a diminished burst release and 18 days of NO release in the range of 0.5–4 × 10–10 mol cm−2 min−1 similar to the NO release from healthy endothelium. NO-releasing SDVGs were cytocompatible, significantly enhanced EC proliferation and migration and diminished bacterial viability. The newly developed SNAP-loaded MWCNT-OH has a great potential to develop NO releasing biomaterials with a prolonged, controlled NO release promoting in-situ endothelialization and tissue integration in vivo, even as an approach towards personalized medicine.

Preparation of Lateral Flow PVDF Membrane via Combined Vapor- and Non-Solvent-Induced Phase Separation (V-NIPS).

A large pore size Poly(vinylidene fluoride) (PVDF) membrane was prepared by the V-NIPS method using PVDF/N, N-dimethylacetamide (DMAc)/Polyvinyl pyrrolidone (PVP)/Polyethylene glycol (PEG) system. Firstly, the effect of different additive ratios on the membrane morphology and pore size was studied, and it was found that when the PVP:PEG ratio was 8:2, PVDF membranes with a relatively large pore size tend to be formed; the pore size is about 7.5 µm. Then, the effects of different exposure time on the membrane morphology and pore size were investigated, and it was found that as the vapor temperature increased, the pores on the surface of the membrane first became slightly smaller and then increased. Finally, the effects of different vapor temperatures on the membrane properties were discussed. The results showed that the as-prepared membrane exhibited suitable capillary flow rate and similar performance compared with a commercially available membrane in colloidal gold tests. The likely cause is that the amount of negative charge is less and the capillary migration rate is too fast. This paper provides a reference for the preparation of PVDF colloidal gold detection membrane.

Study on Mechanical Properties of Polyurethane Cross-Linked P(E-co-T)/PEG Blended Polyether Elastomer.

To improve the mechanical properties of polyurethane cross-linked poly (ethylene oxide-co-tetrahydrofuran) (P(E-co-T)) elastomers at room temperature, using poly (ethylene oxide-co-tetrahydrofuran) and high-molecular-weight polyethylene glycol (PEG) as raw materials and polyisocyanate N100 as curing agent, a series of polyurethane cross-linked blended polyether elastomers were prepared by changing the elastomer-curing parameter R value (n(-NCO)/n(-OH)) and P(E-co-T)/PEG ratio. Equilibrium swelling measurements showed that the chemical cross-linkage of the elastomers tended to decrease with the decreasing R value, the average molecular weight (Mc) of the network chain increased, and the density of the network chain (N0) decreased. Wide-angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC) tests showed that PEG chain segments within the elastomers crystallized at room temperature, while the crystallinity increased with decreasing R value and increasing PEG content. The mechanical property tests showed that the elongation at break tended to decrease with increasing R value; the tensile strength first increased and then decreased. At R value 0.9, the elastomer presented good comprehensive mechanical properties. In addition, the mechanical properties of polyurethane cross-linked P(E-co-T)/PEG blended polyether elastomer showed an increasing trend with the increase in PEG content when the curing parameter of 0.9 remained unchanged.

Preparation of high-performance chitosan adsorbent by cross-linking for adsorption of Reactive Red 2 (RR2) dye wastewater

In this study, high-performance adsorbents were developed by modifying chitosan (CS) with polyethylene glycol (PEG) and formaldehyde. The prepared chitosan beads were tested for adsorption in Reactive Red 2 (RR2) dye wastewater. All the prepared samples were characterized by FI-IR, DSC, XRD, and SEM. The effects of different pH, temperature, PEG molecular weight, and PEG content on the adsorption performance of RR2 were investigated. The results showed that the adsorption equilibrium of RR2 dye was consistent with the Langmuir model and the pseudo-second-order kinetic model. The negative values of (∆G 0 ) suggested that this adsorption process was spontaneous. At 30 ℃, when the ratio of CS and PEG (MPEG=4000) was 1:1, the maximum adsorption capacity of PEGylated chitosan beads (CS/4000P-1) was 2334.8 mg·g -1 . This high adsorption performance is mainly attributed to the protonation of NH 3 + groups on the surface of CS/4000P-1 which enhances its electropositivity. In addition, the CS/4000-1 pore structure is enriched to further improve the adsorption performance. For the regeneration investigation, HCl regent was found to have a fine regeneration effect, and the beads showed the pH-dependent swelling behavior. • High amino PEGylated chitosan beads (CS/4000P-1) have excellent adsorption capacity for RR2 dyes. • The maximum adsorption capacity of CS/4000P-1 is 2334.77 mg·g -1 . • The regeneration capacities of the material are also high.

A semi-transparent polyurethane/porous wood composite gel polymer electrolyte for solid-state supercapacitor with high energy density and cycling stability

In recent years, more and more people have realized the importance of green and sustainable development. Wood as the most abundant natural biodegradable material on the earth, the preparation of high strength transparent wood (TW) by filling the delignified wood (DW) with resin is a hot research topic at present. Taking this as inspiration, here gel polymer electrolytes (GPEs) with high ionic conductivity were prepared by using DW as substrate, polyurethane (PU) with different ratios of polyethylene glycol (PEG) to 2,2-bis(hydroxymethyl)propionic acid (DMPA) as filling polymer matrix and lithium perchlorate (LiClO4) as electrolyte through vacuum perfusion method, and applied in solid-state supercapacitors (SCs) with activated carbon as working electrodes. The cell cavity retained in DW provided a controllable ion transport channel, which further improved the efficiency of ion transport and storage. The synthesized DW-PU1.00-GPE possessed a splendid ionic conductivity of 2.90 × 10−2 S cm−1 at room temperature (RT). The solid-state SCs assembled with the DW-PU1.00-GPE also displayed the highest specific capacitance of 157.7 F g−1 at 0.3 A g−1, the outstanding Ecell of 11.49 W h kg−1 and a long cycling life of 4000 cycles with 95 % capacitance retention and nearly 100 % coulomb efficiency. The DW-PU-GPEs achieve efficient Li+ transport with the help of rich internal cavities, especially showing excellent ion conductivity which possess a great development prospect in the application of SCs and broaden the application of wood in the field of electrochemistry.

Preparation and structure-properties of crosslinking organic montmorillonite/polyurethane as solid-solid phase change materials for thermal energy storage

In order to solve the leakage problem of commonly used polyethylene glycol (PEG) phase change material (PCM), PEG reacted with 4′ 4-diphenylmethane diisocyanate (MDI) to prepare the polyurethane-based solid-solid phase change material (PU-SSPCM) by the two-step solvent method, and the influence of organic montmorillonite (OMMT) on the phase transition property and crystallization capacity of PU-SSPCM was first studied. The solid-solid phase change polyurethane materials were successfully prepared when the molar ratio of PEG to MDI was 0.75, and the organic montmorillonite acted as a crosslinking heterogeneous nucleating agent to improve the temperature control capacity, the crystallization ability and the thermal stability of the solid-solid phase change polyurethane material. When the addition of OMMT was 0.5 wt%, the phase change enthalpy of PU-SSPCM increased to 106.8J/g from 95.46J/g, a constant temperature platform appeared for about 300 s during both the heating and cooling process, thus demonstrating excellent temperature control ability. The relative crystallinity increased to 74.8% from 66.5% and the initial thermal weight loss temperature was increased from 348 °C to 368 °C. • Organic montmorillonite acted as a crosslinking heterogeneous nucleating agent. • Organic montmorillonite enhanced the temperature control capacity the system. • The composites possessed excellent crystallization ability and thermal stability.

Synthesis and performance evaluation of polymeric surfactant from rice husk and polyethylene glycol for the enhanced oil recovery process

A tertiary recovery technique is needed to recover the remained oil in the oil field after primary and secondary recoveries, which can only recover approximately 30–50% of the total oil. This study investigated the synthesized polymeric surfactants from rice husk and polyethylene glycol (PEG) for the enhanced oil recovery (EOR) process as a tertiary recovery technique. The rice husk was used as sodium lignosulfonate (SLS) surfactant production feedstock. SLS-PEG polymer surfactant from rice husk has not been widely studied, especially for the EOR process. This study has comprehensively investigated the effect of PEG concentration on the polymeric surfactant properties. The surfactants were characterized using Fourier transform-Infrared (FT-IR) analysis. Several other tests were also conducted, including surfactant compatibility, viscosity, thermal stability, interfacial tension (IFT), and phase behavior. It was found that the PEG introduction to the SLS surfactant could increase the hydrophilic property of the polymeric surfactant due to the presence of the C−O−C group. In addition, the IFT value decreased with the increase in the PEG concentration due to the increase in the hydrophilic property. However, the IFT value decreased when the PEG concentration was too high. The lowest IFT value was obtained at the SLS to PEG ratio of 1:0.8. It produced the highest increase in the additional recovered oil after brine flooding. The results showed that the rice husk, which is agricultural waste, could be utilized as a feedstock for the surfactant production.

Experimental study on thermophysical parameters of a solar assisted cascaded latent heat thermal energy storage (CLHTES) system

The low thermal conductivity of PCMs limited thermal storage/release properties of latent heat thermal energy storage (LHTES) systems, and the performance enhancement of PCMs thermal conductivity, PCMs stages and operating conditions needed to be investigated simultaneously. This study selected polyethylene glycol (PEG) as PCM and expanded graphite (EG) as matrix to prepare composite PCMs (CPCMs). When the mass ratio of PEG:EG was 9:1 and CPCM density was 954.8 kg/m3, the thermal performance was excellent without leakage. Compared to the single-stage LHTES tank, the heat storage/release time of four-stage cascaded LHTES (CLHTES) tank was 1040/320s longer, the heat storage/release rate was 0.92/1.04 times and the maximum exergy efficiency was 10.6% higher. For the four-stage CLHTES tank, its heat storage/release rate was fast and efficiency was high at the inlet temperature of 75/10 °C and flow rate of 3 L/min. When the four-stage CLHTES tank was used in a solar heating system, a wider range of phase change temperatures (31.4–55.2 °C) and a longer delay time of temperature peak (2290s) were obtained. Therefore, the CLHTES tank with high thermal conductivity CPCMs could play a significant role in improving the storage/release performance of renewable energy sources.

Excellent Lubricity of PVA/PEG/CS Composite on Ceramic Surface and Stainless Steel Friction Pair

At present, polymers such as polyethylene glycol (PEG) and chitosan (CS) are widely studied because of their excellent lubricating properties. Herein, powder combinations of different mass ratios are obtained by changing the mass of CS, and polymer films are obtained by hot pressing on the surface of the aluminum disk after microarc oxidation (MAO). The structure and crystallinity of the polymer composite film are characterized by X‐ray diffraction (XRD), Fourier‐transform infrared (FTIR), and X‐ray photoelectron spectroscopy (XPS), which show that there is no chemical reaction between various substances. The tribological properties of the composite film are evaluated. Experiments show that when the mass ratio of polyvinyl alcohol (PVA), PEG, and CS is 5:5:1.5, the composite film has excellent lubrication performance, and the friction coefficient reaches 0.068 under long‐time running in. This effect meets the social requirements for lubrication performance to a certain extent and is expected to replace some mature solid lubricants.