Increase In Polyethylene Glycol Content Research Articles

Cellulose Nanofiber/Polyethylene Glycol Composite Phase Change Thermal Storage Gel Based on Solid-gel Phase Change

In this paper, cellulose nanofiber (CNF)/ polyethylene glycol (PEG) composite aerogel phase change materials (CNPCMs) were prepared utilizing porous carrier support and freeze-drying. The solid-liquid phase change to solid-gel phase change was realized, which solved the problems of PEG flow, leakage, and shape instability. The physical properties and chemical compatibility of CNPCMs were studied, and the results showed that CNPCMs ensured the overall structure stability through internal hydrogen bonding, and they were only a physical bond with each other without chemical reaction. With the increase in PEG content, the thermal conductivity of CNPCMs increased from 0.22 W/m·K to 0.33 W/m·K. The thermal exposure experiment and thermogravimetric analysis (TGA) experiment have shown that CNPCMs have good shape stability at 75 ℃ and good thermal stability below 320 ℃. In summary, the experimental results indicated that the maximum content of PEG in CNPCMs was 78 % with an optimal content of 66.7 %. The sample corresponding to the optimal content was CNPCM2 with an enthalpy of 167.9 J/g for melting and 146.1 J/g for solidification. As a thermal storage material with good thermodynamic performance, CNPCM2 has enormous potential in the storage of solar collectors.

Preparation and characterization of amphiphilic, biodegradable, waterborne polyurethanes without using organic solvent and catalyst.

Traditionally, waterborne polyurethanes (WPUs) are prepared using toxic organic solvents and catalysts. These WPUs are non-biodegradable and are buried or incinerated after the expiration date. This has adverse effects on the environment and human health, which limits the applications of WPUs. Herein, a special synthetic method was developed for biodegradable waterborne polyurethane (BWPU) by adding hydrophilic prepolymers into WPU prepolymers without using organic solvents and catalysts. Different proportions of polyethylene glycol (PEG) were introduced into polycaprolactone (PCL)-based BWPUs to improve the comprehensive properties. Results showed that as the PEG content was increased from 0 to 16 wt%, the solid content of BWPU increased from 34.8 wt% to 53.1 wt%, while the tensile strength and Young's modulus of BWPU films increased from 21.81 MPa to 56.83 MPa and 8.08 MPa to 19.4 MPa, respectively. However, the elongation at break did not decrease significantly, but still reached 827.17%. With an increase in PEG content, the crystallinity and phase separation decreased, while the hydrophilicity and surface energy increased for BWPU films. In addition, the prepared BWPUs had good biodegradability in PBS/lipase solution. The mass loss of BWPU without PEG reached 6.3 wt% after 4 weeks of degradation, whereas the mass losses of BWPUs with PEG reached 2.3-4.3 wt%. Obviously, the introduction of PEG did not increase biodegradability. Thus, the higher the PCL content, the faster the biodegradation rate. This work would provide an effective method for the preparation of ecofriendly biodegradable BWPU with excellent comprehensive properties.

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.

Flexible and degradable polycaprolactone based phase change composites for thermal energy management

Electrospun fibrous membranes have potential applications in phase change materials(PCMs)for thermal energy storage and temperature regulation. However, challenges remain in the development of eco-friendly PCMs with flexibility and no leakage. Here, two kinds of degradable polymers, polycaprolactone (PCL) and polyethylene glycol (PEG) are selected to fabricate PCL@PEG shell@core phase change fibers composites by coaxial electrospinning technique, where supporting matrix PCL acts as shell layer and phase change ingredient PEG as core layer. An increase in PEG content of PCL@PEG would favor the gradual improvement in latent heat, and the maximum melting enthalpy could reach up to 39.5 kJ/kg. Also, the melting/crystallization temperature of PCL@PEG with various PEG content almost retain unchanged, and the temperature range is about 39 °C–33 °C. Besides, all PCL@PEG composites could be bendable coming from the designed shell@core structure and the desired mechanical properties of PCL. It is noteworthy that the shape-stabilized PCL@PEG composites possess the higher thermal reliability and temperature regulation capacity. The method thus opens an effective way for degradable phase change composites to simultaneously be flexible and leakage-free.

Study on structures and properties of isotropic pitches and carbon fibers from co-carbonization of aromatic-rich distillate oil and polyethylene glycol

Obtaining cost-competitive carbon fibers with excellent mechanical properties remains a great challenge. Here we report the co-carbonization of polyethylene glycol (PEG) and an aromatic-rich distillate oil (HCT0-RF) to prepare isotropic pitches that have superior spinnability for the production of carbon fibers. Among all of the carbon fiber productions, H-P10-CFs exhibited the best tensile strength of 1050 MPa and elongation of 2.5 %, respectively, at the breaking point. We reason that the addition of PEG into HCTO-RF can effectively increase the yield of isotropic pitches, accompanied by restricting the appearance of the mesophase spheres. The amount of aliphatic carbon in spinnable pitches were observed to increase with the amount of PEG. Thus, the changes in molecular structure can improve the rheological properties of spinnable pitch and enhance the spinnability. In addition, the increase of aliphatic components can accelerate the oxidative reaction and promote the stabilization efficiency. Unfortunately, excessive aliphatic components would inevitably cause higher oxygen uptake content, which deteriorate the uniformity of the fiber structures during carbonization process. With the increase of PEG content, the tensile strength of these carbon fibers increased first and then decreased. The optimized PEG content should be in the range of 5–10 wt%. The PEG acted as the co-carbonization agent provides new perspective in the field of carbon fiber production.

Design of aluminum trihydroxide and P‐N core‐shell structures and their synergistic effects on halogen‐free flame‐retardant polyethylene composites

AbstractIn order to improve the performance of inorganic/organic composites, aluminum trihydroxide (ATH) core composites with a styrene‐ethylene‐butadiene‐styrene block copolymer grafted with maleic anhydride (MAH‐g‐SEBS) shell phase, and P‐N flame retardant as a synergistic agent, were prepared through an interface design. The effects of polyethylene glycol (PEG) content on the interfacial interaction, flame retardancy, thermal properties, and mechanical properties of high‐density polyethylene (HDPE)/ATH composites were investigated by small angle X‐ray diffraction, rotational rheometer, limiting oxygen index, thermogravimetric analysis (TGA), and tensile testing. The ATH synergistic effects of P‐N flame‐retardant improved the combustion performance of HDPE/ATH/PEG(3%)/MAH‐g‐SEBS/P‐N (abbreviated as HDPE/MH3/M‐g‐S/P‐N) composite by forming more carbon layer, increased the elongation at break from 21% to 558% compared to HDPE/ATH, and increased the interface thickness from 0.447 to 0.891 nm. SEM results support the compatibility of ATH with HDPE increased and the interfacial effect was enhanced. TGA showed the maximum decomposition temperature of the two stages and the yield of the residue at high temperature increased first and then decreased with the increase of PEG content. Rheological behavior showed the storage modulus, complex viscosity, and the relaxation time initially increased and then decreased with the increase of PEG content indicating PEG, M‐g‐S, and ATH powder gradually formed a partial coating, then a full coating, and finally an over‐coated core‐shell structured model.

Investigation of efficiency of a novel, zinc oxide loaded TEMPO-oxidized cellulose nanofiber based hemostat for topical bleeding

Lethal bleeding due to street accidents, natural calamities, orthopedic/dental surgeries, organ transplantation and household injuries, is the leading cause of morbidity and mortality. In the current study, zinc oxide (ZnO) was incorporated in TEMPO-oxidized cellulose nanofiber (TOCN) and polyethylene glycol (PEG) polymer system for hemorrhage control by freeze drying method. SEM and XRD data showed the presence of ZnO in the porous structure. FT-IR analysis showed that, successful conjugation occurs among the TOCN and PEG. The results revealed that, the incorporation of ZnO and higher concentrations of PEG increased the degradability but decreased swelling of the scaffolds. The increase in PEG content and ZnO incorporation significantly decreased the bleeding time in rabbit ear arterial bleeding model. Further, the incorporation of ZnO enhanced the antibacterial property of TOCN-PEG. The results suggested that excellent hemostatic and mechanical properties of the TOCN-5% PEG-ZnO might contribute in controlling bleeding and reducing post traumatic dermal bacterial infection.

Polyethylene glycol: An effective agent for isocyanate-based polyimide foams with enhanced foaming behavior and flexibility

A series of polyimide foam materials were prepared via one-step process, and the effect of polyethylene glycol on the morphology and properties of the foams was investigated. The results showed that the mean cellular diameter increased from 0.49 to 0.57 mm with the increase of polyethylene glycol content. Meanwhile, with the addition of polyethylene glycol, the tensile strength of polyimide foams increased from 18 to 23 kPa. It was proved that the foaming behavior and flexibility of polyimide foams were greatly improved due to the introduction of polyethylene glycol. As a kind of chain extender, polyethylene glycol reacted with isocyanate to form the flexible urethane segment, which improved the flexibility of polyimide molecular chain and promoted foaming behavior. In addition, all the foams exhibited fine thermal stability with temperature at 5% weight loss of about 350°C. The limiting oxygen index values of the prepared polyimide foams decreased with the increase of polyethylene glycol content, while the heat release rate increased, indicating certain decrease of the flame retardant properties. However, the fine cell structure can still be observed under the residual carbon structure after the burning, indicating fine flame retardancy.

Synthesis of Higher Alcohols via Syngas on Cu/Zn/Si Catalysts. Effect of Polyethylene Glycol Content

Cu/Zn/Si catalysts with different polyethylene glycol (PEG) content were prepared by a complete liquid-phase method, and characterized by XRD, H2-TPR, N2-adsorption, and XPS. The influence of PEG content on the higher alcohols synthesis from syngas was investigated. The results showed that addition of PEG can influence the texture and surface properties of the catalysts, and therefore affect their activity and product distribution. With an increase in PEG content, BET surface area, Cu crystallite size and surface active ingredient content of the catalysts first increased and then decreased, the CO conversion had similar variation tendency. However, the pore volume and pore diameter of the catalyst increased, and the binding energy of the active component and the content of Cu2O decreased, which resulted in higher catalyst selectivity towards higher alcohols. The highest C2+OH selectivity in total alcohols was 60.6 wt %.

INVESTIGATION ON THE EFFECT OF THE POLYETHYLENE GLYCOL ON THE ELECTROPHORTIC DEPOSITION OF ALUMINA AND ZIRCONIA

This work is a study of the effect of polyethylene glycol (PEG) on electrophoretic deposition) EPD) of alumina and zirconia particles. The effect of polyethylene glycol as a binder material and the toluene as a dielectric liquid, on the pH of suspension, the final thickness and green density of the deposed parts were studied. There was a difference in the behavior of polyethylene glycol when added for the alumina suspension and the zirconia suspension. The increase in polyethylene glycol was useful to deposit the zirconia more than alumina. The pH for both alumina and zirconia suspension increases with the increase of polyethylene glycol content and with the addition of toluene due to increase of the OH– concentration in the suspension. This increase of pH enhances the particle surface charge and enhances the deposition rate, which led to the increase of density of the deposit

Effect of Polyethylene Glycol on Bis(2‐hydroxyethyl) terephthalate‐Based Polyurethane/Alginate pH‐Sensitive Blend for Oral Protein Delivery

ABSTRACTPolyurethanes (PUs) are synthesized by reacting two polyols, namely bis(2‐hydroxyethyl) terephthalate (BHET) and polyethylene glycol (PEG), taken in four different ratios and hexamethylene diisocyanate, where the polyol content is slightly higher than the stoichiometrically required amount. BHET is obtained by the glycolysis of polyethylene terephthalate waste. The synthesized PUs are blended with sodium alginate in the ratio of 7:3 and then cross‐linked by calcium chloride to get a pH‐sensitive protein (bovine serum albumin, BSA) carrier. X‐ray diffraction patterns of different PU compositions indicate the presence of amorphous phase. The hydroxyl value of OH‐terminated PUs is found to be increasing with increasing amount of PEG in the composition. PEGylated PU shows higher water uptake and protection against hemolysis with a rising amount of PEG in the PU. Fourier transform infrared spectroscopy of the blend shows characteristic peaks for both PU and alginate distinctly, indicating good dispersion of both the polymers. pH responsive swelling behavior in different pH media corresponding to the gastrointestinal tract (pH 1.2 and 7.4) is investigated for all the prepared blends. The minimum degree of swelling is observed for PU with the maximum amount PEG at pH 1.2, whereas the degree of swelling of the same PU significantly increased at pH 7.4. BSA encapsulation efficiency of the blends increases with an increase in PEG content in the PU and varies within the range of 88–99%. The release profile of BSA at pH 7.4 is found to be similar as observed in the swelling study.

Delivery of kinesin spindle protein targeting siRNA in solid lipid nanoparticles to cellular models of tumor vasculature

The ideal siRNA delivery system should selectively deliver the construct to the target cell, avoid enzymatic degradation, and evade uptake by phagocytes. In the present study, we evaluated the importance of polyethylene glycol (PEG) on lipid-based carrier systems for encapsulating, and delivering, siRNA to tumor vessels using cellular models. Lipid nanoparticles containing different percentage of PEG were evaluated based on their physical chemical properties, density compared to water, siRNA encapsulation, toxicity, targeting efficiency and gene silencing in vitro. siRNA can be efficiently loaded into lipid nanoparticles (LNPs) when DOTAP is included in the formulation mixture. However, the total amount encapsulated decreased with increase in PEG content. In the presence of siRNA, the final formulations contained a mixed population of particles based on density. The major population which contains the majority of siRNA exhibited a density of 4% glucose, and the minor fraction associated with a decreased amount of siRNA had a density less than PBS. The inclusion of 10mol% PEG resulted in a greater amount of siRNA associated with the minor fraction. Finally, when kinesin spindle protein (KSP) siRNA was encapsulated in lipid nanoparticles containing a modest amount of PEG, the proliferation of endothelial cells was inhibited due to the efficient knock down of KSP mRNA. The presence of siRNA resulted in the formation of solid lipid nanoparticles when prepared using the thin film and hydration method. LNPs with a relatively modest amount of PEG can sufficiently encapsulate siRNA, improve cellular uptake and the efficiency of gene silencing.

多孔質ポリジメチルシロキサン膜を利用した低圧膜ろ過による有機溶媒含有廃液からの溶媒回収

Porous polydimethylsiloxine (PDMS) membranes were prepared using polyethylene glycol (PEG) as pore forming agent. After the PDMS-PEG membranes were prepared, they were immersed in hot water to remove PEG from the membranes to prepare the PDMS porous membranes. A dense PDMS membrane was also prepared. The degree of weight swelling of the membranes in toluene increased with an increase in PEG content, indicating the porosity of the membranes increased with PEG content. The solvent permeation across the membranes was measured by low-pressure (0.2-0.3MPa) driven filtration. Pure toluene and waste organic liquid containing fine solid particle (200 µm) and organic solvent were used as feed solutions. Toluene permeation increased with increasing the PEG content. The solid particle weight concentration in waste organic liquid was 7.2wt%, however, almost pure solvent was obtained by the filtration: the solid particle weight concentration was less than 1wt% in permeate.

Studies on fouling by natural organic matter (NOM) on polysulfone membranes: Effect of polyethylene glycol (PEG)

Polysulfone membranes were prepared via phase inversion technique by using polyethylene glycol with molecular weights of 400, 1500 and 6000Da as pore forming agent in dope formulation. The performance of membrane was characterized using humic acid and water sample taken from Sembrong River, Johor, Malaysia was used as natural organic matter sources. Membrane properties were also characterized in terms of mean pore radius, pure water flux, humic acid rejection and fouling resistance. The results indicated that the pure water flux and mean pore radius of membranes increased with the increase of PEG content. Fourier transform infrared spectroscopy results revealed the presence of hydrophilic component in PSf/PEG blend with the significant appearance of O–H peak at 3418.78cm−1. Scanning electron microscopy analysis revealed the presence of finger-like structure for all membranes and the structure intensified as PEG content was increased. The results obtained from the fouling study indicated that the membrane with the lowest PEG content and molecular weight has an excellent performance in mitigating fouling.

Investigation on the Influence of Different Compatibilizers on Polycarbonate and High Density Polyethylene Blends: Mechanical Properties, Thermal Properties, Morphology, and Chemical Resistance

This investigation focused on a systematic approach of selecting the best possible polycarbonate/high density polyethylene (PC/HDPE) blend ratio and a suitable compatibilizer to improve the notch sensitivity, craze, and cracking tendency of PC. Among five different compatibilizers, polyethylene glycol (PEG) was found to be more effective based on mechanical performance and changes in phase morphology. The phase morphology of dispersed HDPE phase changed from elongated domain to fine spherical domain, and the tensile modulus and heat distortion temperature of PC/HDPE blend increased with increase in PEG content. DSC analysis showed an inward shift in the glass transition temperature (Tg), indicating enhanced compatibility between the PC and HDPE phases. Furthermore, PEG compatibilized PC/HDPE (80/20) blend was found to have very good notch performance and chemical resistance compared to PC. Hence, this blend can be used to design products with intricate shapes with less notch sensitivity and high chemical resistance with the superior mechanical performance of PC.

Poly(oligo(ethylene glycol)acrylamide) Brushes by Surface Initiated Polymerization: Effect of Macromonomer Chain Length on Brush Growth and Protein Adsorption from Blood Plasma

Three hydrolytically stable polyethyleneglycol (PEG)-based N-substituted acrylamide macromonomers, methoxypolyethyleneglycol (350) acrylamide (MPEG350Am) methoxypolyethyleneglycol (750) acrylamide(MPEG750Am) and methoxypolyethyleneglycol (2000)acrylamide (MPEG2000Am) with increasing PEG chain length were synthesized. Surface-initiated aqueous atom transfer radical polymerization (ATRP) using CuCl/1,1,4,7,10,10-hexamethyl triethylene tetramine (HMTETA) catalyst was utilized to generate dense polymer brushes from these monomers via an ester linker group on the surface of model polystyrene (PS) particles. The molecular weight, hydrodynamic thickness, and graft densities of the grafted polymer layers were controlled by changing the reaction parameters of monomer concentration, addition of Cu(II)Cl2, and sodium chloride. The graft densities of surface-grafted brushes decreased with increasing PEG macromonomer chain length, 350 > 750 >> 2000, under similar experimental conditions. The molecular weight of grafts increased with increase in monomer concentration, and only selected conditions produced narrow distributed polymer chains. The molecular weight of grafted polymer chains differs significantly to those formed in solution. The hydrodynamic thicknesses of the grafted polymer layers were fitted to the Daoud and Cotton model (DCM) for brush height on spherical surfaces. The results show that the size of the pendent groups on the polymer chains has a profound effect on the hydrodynamic thickness of the brush for a given degree of polymerization. The new PEG-based surfaces show good protection against nonspecific protein adsorption from blood plasma compared to the bare surface. Protein adsorption decreased with increasing surface density of grafted polymer chains. Poly(MPEG750Am) brushes were more effective in preventing protein adsorption than poly(MPEG350Am) even at low graft densities, presumably due to the increase in PEG content in the grafted layer.

Preparation and thermal properties of polyethylene glycol/expanded graphite blends for energy storage

Expanded graphite is a promising heat transfer promoter due to its high conductivity, which improves the thermal conductivity of organic phase change materials. Moreover, it can also serve as supporting materials to keep the shape of the blends stable during the phase transition. After various investigation, the results showed that the maximum weight percentage of polyethylene glycol was as high as 90% in this paper without any leakage during the melting period, with the latent heat of 161.2 J g −1 and the melting point of 61.46 °C. It was found that the value of the latent heat was related to the polyethylene glycol portion, increased with the increase in polyethylene glycol content. Moreover, the measured enthalpy of the composite phase change materials was proportional to the mass ratio of the polyethylene glycol component. The melting temperatures were almost the same with different ratios of composites. The conductivity of blends was improved significantly with the high value of 1.324 W m −1 K −1 compared to the pure polyethylene glycol conductivity of 0.2985 W m −1 K −1.

Biocompatibility and biodegradation of poly(hydroxybutyrate)/poly(ethylene glycol) blend films.

Using chloroform as co-solvent, a series of poly(3-hydroxybutyrate) (PHB) and polyethylene glycol (PEG) blend materials with different ratio ranging from 80 : 20 (wt %) to 20 : 80 (wt %) were prepared by solution blend. The blood-compatibility was evaluated by means of platelet clotting time test and exploring its morphological changes. The results showed that PEG played an important role in resisting platelet adhesion. With the increased addition of PEG, the clotting times became longer and the number of platelet adhesion decreased apparently. All platelets were in discrete state, no pseudopodium had been found and no collective phenomenon had been happened. The cell-compatibility was evaluated via Chinese Hamster Lung (CHL) fibroblast cultivation in vitro. The cells cultured on the matrix spread and proliferated well. With the increase of PEG content in the blend films, the number of live cells became more and more. These results indicated that PHB exhibited satisfying cell-compatibility and the addition of PEG also could improve the cell-compatibility of PHB. The biodegradation experiment indicated that the degradation of PHB/PEG was accelerated by enzyme in vitro and the blending of PEG was favorable to degradation.

Solute diffusion through degradable semicrystalline polyethylene glycol/poly(l-lactide) copolymers

The diffusion of C.I. direct orange 34(MW=299) and benzoic acid(MW=122) through degraded semicrystalline polyethylene glycol(PEG)/poly(L-lactide)(PLLA) block copolymers with various PEG contents and PEG segment lengths at 37°C was studied by UV-visible spectroscopy, differential scanning calorimetry(DSC), wide angle X-ray diffractometer (WAXS) and scanning electron microscopy(SEM). The influences of the PEG contents, PEG segment lengths and hydrolytic degradation of PEG/PLLA copolymers on the solute diffusion coefficient and mode for transport were investigated. It is concluded that the diffusion rate increases with the increase of PEG contents and PEG segment lengths in PEG/PLLA copolymers. This is understandable that the increase of PEG content and PEG segment length both make the degree of crystallinity decrease. The steady state of mass flux could not be reached at the diffusion times up to 1000 h, because the copolymers underwent hydrolysis reaction during this period. Furthermore, it is understood that the characteristic time of diffusion as defined by the square of film thickness at an instant of time over the diffusion coefficient of solute through polymer decreases with the increasing diffusion time.