High Molecular Weight Polyethylene Oxide Research Articles

In vitro test methods for evaluating high molecular weight polyethylene oxide polymer induced hemolytic and thrombotic potential

To combat opioid abuse, the U.S. Food and Drug Administration (FDA) released a comprehensive action plan to address opioid addiction, abuse, and overdose that included increasing the prevalence of abuse-deterrent formulations (ADFs) in opioid tablets. Polyethylene oxide (PEO) has been widely used as an excipient to deter abuse via nasal insufflation. However, changes in abuse patterns have led to unexpected shifts in abuse from the nasal route to intravenous injection. Case reports identify adverse effects similar to thrombotic thrombocytopenic purpura (TTP) syndrome following the intravenous (IV) abuse of opioids containing PEO excipient. Increased risk of IV opioid ADF abuse compared to clinical benefit of the drug led to the removal of one opioid product from the market in 2017. Because many generic drugs containing PEO are still in development, there is interest in assessing safety consistent with generic drug regulation and unintended uses. Currently, there are no guidelines or in vitro assessment tools to characterize the safety of PEO excipients taken via intravenous injection. To create a more robust excipient safety evaluation tool and to study the mechanistic basis of HMW PEO-induced TMA, a dynamic in vitro test system involving blood flow through a needle model has been developed.

Measurement and control of extensional viscosity in barrier coating dispersions

This study aimed to understand the effect of various rheological additives on the extensional viscosity of barrier coating dispersions, as well as to understand the role extensional viscosity plays in stabilizing a liquid curtain. The apparent extensional viscosity was measured using two devices that create accelerating flows: a capillary viscometer and an orifice rheometer. Additives tested include several polyvinyl alcohols, a high molecular weight polyethylene oxide, and carboxymethylcellulose. Extensional viscosity plays a significant role in stabilizing a liquid curtain, as it slows down hole expansion and prevents impurities and disturbances from causing holes in the first place. Some of the additives could substantially increase the extensional viscosity of the dispersions without increasing the shear viscosity outside the typical range of processability for a curtain coater. Some of the additives exhibited coil-stretch transition, meaning they start increasing extensional viscosity above a certain extension rate. Polymers with low chain lengths exhibited finite extensibility, which indicates the polymer chain has fully extended and cannot provide further extensional viscosity, even though the extending force is increased. Polymeric additives with stiff or branched chains significantly raised shear viscosity without increasing extensional viscosity. Both methods could reliably measure extensional viscosity in curtain coating barrier dispersions.

Crystallization in blend of polycaprolactone and high molecular weight polyethylene oxide

The concentration distribution in blend of polyethylene oxide (PEO)/polycaprolactone (PCL) and subsequent crystallization were investigated with differential scanning calorimetry, in-situ small angle X-ray scattering and wide angle X-ray scattering. By using PEOs with a molecular weight of 1 × 106 g/mol (PEO1M) and 1 × 105 g/mol (PEO100k), respectively, it is revealed that in initial blend the concentration of PEO1M in PEO-rich region is higher than that determined by miscibility. This non-equilibrium distribution induced by crystallization is maintained after melting, since slow relaxation of PEO1M hinders the redistribution process. Crystallization behavior of blend with 25 % of PEO1M at different melting temperatures was further investigated. The crystallinity shows no dependence on melting temperature, while the long period of PEO1M decreases continuously when melting temperature exceeds 140 °C. This decrease indicates more PCL chains diffuse into PEO-rich regions with increasing temperature and molten PCL chains reduce the entanglement number of PEO1M as solvent. Moreover, the periodicity of PEO1M lamellae becomes worse when crystallization proceeds faster, which is related to slower exclusion of PCL chains.

Bio-Resorption Control of Magnesium Alloy AZ31 Coated with High and Low Molecular Weight Polyethylene Oxide (PEO) Hydrogels.

Magnesium AZ31 alloy has been chosen as bio-resorbable temporary prosthetic implants to investigate the degradation processes in a simulating body fluid (SBF) of the bare metal and the ones coated with low and high-molecular-weight PEO hydrogels. Hydrogel coatings are proposed to control the bioresorption rate of AZ31 alloy. The alloy was preliminary hydrothermally treated to form a magnesium hydroxide layer. 2 mm discs were used in bioresorption tests. Scanning electron microscopy was used to characterize the surface morphology of the hydrothermally treated and PEO-coated magnesium alloy surfaces. The variation of pH and the mass of Mg2+ ions present in the SBF corroding medium have been monitored for 15 days. Corrosion current densities (Icorr) and corrosion potentials (Ecorr) were evaluated from potentiodynamic polarisation tests on the samples exposed to the SBF solution. Kinetics of cumulative Mg ions mass released in the corroding solution have been evaluated regarding cations diffusion and mass transport parameters. The initial corrosion rates for the H- and L-Mw PEO-coated specimens were similar (0.95 ± 0.12 and 1.82 ± 0.52 mg/cm2day, respectively) and almost 4 to 5 times slower than that of the uncoated system (6.08 mg/cm2day). Results showed that the highly swollen PEO hydrogel coatings may extend into the bulk solution, protecting the coated metal and efficiently controlling the degradation rate of magnesium alloys. These findings focus more research effort on investigating such systems as tunable bioresorbable prosthetic materials providing idoneous environments to support cells and bone tissue repair.

Continuous Monitoring of the Hydration Behavior of Hydrophilic Matrix Tablets Using Time-Domain NMR.

Time-domain NMR (TD-NMR) was used for continuous monitoring of the hydration behavior of hydrophilic matrix tablets. The model matrix tablets comprised high molecular weight polyethylene oxide (PEO), hydroxypropyl methylcellulose (HPMC), and polyethylene glycol (PEG). The model tablets were immersed in water. Their T2 relaxation curves were acquired by TD-NMR with solid-echo sequence. A curve-fitting analysis was conducted on the acquired T2 relaxation curves to identify the NMR signals corresponding to the nongelated core remaining in the samples. The amount of nongelated core was estimated from the NMR signal intensity. The estimated values were consistent with the experiment measurement values. Next, the model tablets immersed in water were monitored continuously using TD-NMR. The difference in hydration behaviors of the HPMC and PEO matrix tablets was then characterized fully. The nongelated core of the HPMC matrix tablets disappeared more slowly than that of the PEO matrix tablets. The behavior of HPMC was significantly affected by the PEG content in the tablets. It is suggested that the TD-NMR method has potential to be utilized to evaluate the gel layer properties, upon replacement of the immersion medium: purified (nondeuterated) water is replaced with heavy (deuterated) water. Finally, drug-containing matrix tablets were tested. Diltiazem hydrochloride (a highly water-soluble drug) was employed for this experiment. Reasonable in vitro drug dissolution profiles, which were in accordance with the results from TD-NMR experiments, were observed. We concluded that TD-NMR is a powerful tool to evaluate the hydration properties of hydrophilic matrix tablets.

Crystallization and phase separation in PEDOT:PSS/PEO blend thin films: Influence on mechanical and electrical properties at the nanoscale

Thin films of polymeric blends composed of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) and polyethylene oxide (PEO) were investigated by varying the concentration of the two components over the entire range of compositions and the molecular weight of PEO. Phase separation and crystallization have been studied at different length scales by combining Atomic Force Microscopy (AFM) and Grazing Incidence Wide Angle X-ray Scattering (GIWAXS) using synchrotron light. Several different arrangements in the thin films of the two polymers constituting the blend were observed and discussed in detail, providing information about their reciprocal influence at the micro- and nano-scale. In addition to that, we were able to estimate quantitative nanomechanical and nanoelectrical properties via AFM and finally revealing the dependence of the thin films' physical properties on their composition and structure. By varying the blend composition, we achieved different coating capability, mechanical properties, and electrical conductivity. Furthermore, depending on the PEO molecular weight, the electrical response of the resulting blends’ thin films shows some differences. In the low range concentration, the blend thin films with high molecular weight PEO present coarser conducting paths than in those with the low molecular weight counterparts. For intermediate concentrations, a more effective phase segregation of PEDOT:PSS and PEO is achieved for high molecular weight PEO. These differences are also translated to different electrical conductivity.

Evaporation-controlled dripping-onto-substrate (DoS) extensional rheology of viscoelastic polymer solutions

Extensional flow properties of polymer solutions in volatile solvents govern many industrially-relevant coating processes, but existing instrumentation lacks the environment necessary to control evaporation. To mitigate evaporation during dripping-onto-substrate (DoS) extensional rheology measurements, we developed a chamber to enclose the sample in an environment saturated with solvent vapor. We validated the evaporation-controlled DoS device by measuring a model high molecular weight polyethylene oxide (PEO) in various organic solvents both inside and outside of the chamber. Evaporation substantially increased the extensional relaxation time lambda _{E} for PEO in volatile solvents like dichloromethane and chloroform. PEO/chloroform solutions displayed an over 20-fold increase in lambda _{E} due to the formation of an evaporation-induced surface film; evaporation studies confirmed surface features and skin formation reminiscent of buckling instabilities commonly observed in drying polymer solutions. Finally, the relaxation times of semi-dilute PEO/chloroform solutions were measured with environmental control, where lambda _{E} scaled with concentration by the exponent m=0.62. These measurements validate the evaporation-controlled DoS environment, and confirm that chloroform is a good solvent for PEO, with a Flory exponent of nu =0.54. Our results are the first to control evaporation during DoS extensional rheology, and provide guidelines establishing when environmental control is necessary to obtain accurate rheological parameters.

Experimental Investigation of Polyethylene Oxide Polymer Solutions for Enhanced Oil Recovery in Low-Permeability Carbonate Rocks

SummaryNew experiments using polyethylene oxide (PEO) polymer were performed to evaluate its potential for enhanced oil recovery (EOR) applications in low-permeability reservoirs. This is the first time that high molecular weight PEO solutions have been shown to have favorable transport in low-permeability (~20 md) carbonate cores and the first time PEO has been shown to improve oil recovery in a fractured carbonate core. Rheology measurements in synthetic seawater show the higher viscosity of PEO solutions compares favorably to the viscosity of acrylamide–sodium acrylate (AM-AA) copolymers of similar molecular weight because PEO is less sensitive to hardness and high salinity. Filtration experiments using 0.45 μm cellulose filters show very favorable filtration ratios of PEO with a molecular weight of 4 million g/mol, which is consistent with its favorable transport in low-permeability cores. Four coreflood experiments in Texas Cream Limestone (TC Limestone) cores demonstrate the viability of PEO for EOR in low-permeability carbonate rocks. Single-phase experiments show 4 million g/mol PEO solutions transported through 18 and 28 md TC Limestone cores. Oil recovery experiments show 4 million g/mol PEO solutions transported and was more efficient than waterflooding in aged TC Limestone with favorable retention of 40 µg/g rock. An oil recovery experiment in an artificially fractured TC Limestone core improved oil recovery by a remarkable 15% considering the very large fracture-matrix permeability contrast (>7,000). These experimental results as well as other favorable properties of PEO reported in the literature indicate PEO should be considered for some EOR applications, especially in low-permeability reservoirs.

Addressing Manufacturability and Processability in Polymer Gel Electrolytes for Li/Na Batteries

Gel electrolytes are prepared with Ultra High Molecular Weight (UHMW) polyethylene oxide (PEO) in a concentration ranging from 5 to 30 wt.% and Li- and Na-doped 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (PYR14-TFSI) by a simple procedure consisting of dissolving PEO by melting it directly in the liquid electrolyte while stirring the blend. This procedure is fast, reproducible and needs no auxiliary solvents, which makes it sustainable and potentially easy to scale up for mass production. The viability of the up-scaling by extrusion has been studied. Extrusion has been chosen because it is a processing method commonly employed in the plastics industry. The structure and morphology of the gel electrolytes prepared by both methods have been studied by DSC and FTIR, showing small differences among the two methods. Composite gels incorporation high concentrations of surface modified sepiolite fibers have been successfully prepared by extrusion. The rheological behavior and ionic conductivity of the gels have been characterized, and very similar performance of the extruded and manually mixed gels is detected. Ionic conductivity of all the gels, including the composites, are at or over 0.4 mS cm−1 at 25 °C, being at the same time thermoreversible and self-healing gels, tough, sticky, transparent and stretchable. This combination of properties, together with the viability of their industrial up-scaling, makes these gel electrolyte families very attractive for their application in energy storage devices.

Coating of Laponite on PLA Nanofibrous for Bone Tissue Engineering Application

In this study, electrospun polylactic acid (PLA) nanofibers were coated with osteoinductive Laponite (LAP) nanoplatelets and used as scaffolds for bone tissue engineering. The LAP nanoplatelets were physically crosslinked with high molecular weight polyethylene oxide (PEO) to make a layer of LAP/PEO network around PLA nanofibers with a thickness of 45–175 nm that was controllable through adjusting the concentration of the LAP/PEO solution (0.4, 0.8, and 1.2 wt%). The LAP/PEO layer improved the surface hydrophilicity (water contact angle from 111° to 26°) and thus the cell attachment and proliferation (p ≤ 0.05) by the scaffolds. The LAP nanoplatelets coated on the surface of PLA nanofibers could induce osteodifferentiation on human mesenchymal stem cells (hMSCs) by increasing the ALKALINE PHOSPHATASE (ALP) activity. The expression of specific osteogenic genes (ALP and OSTEONECTIN) at the transcription level (p ≤ 0.001) for the seeded hMSCs proved the osteoinductive effect of coated LAP nanoplatelets for the differentiation of stem cells to osteoblasts without using any external osteogenic inducers. The LAP-coated nanofibers can be used as an excellent scaffold for bone tissue engineering to provide an appropriate environment for direct bone tissue engineering.

A semi-interpenetrating network polymer electrolyte membrane prepared from non-self-polymerized precursors for ambient temperature all-solid-state lithium-ion batteries

Solid polymer electrolytes (SPEs) are currently attracting widespread interest for lithium battery applications due to high safety, low volatility, and the ability to suppress Li dendrites. Herein, a novel all-solid-state polymer electrolyte with semi-interpenetrating network (semi-IPN) structure has been prepared. The semi-IPN SPE is fabricated by thiol-tosylate polycondensation of pentaerythritol terakis (3-mercaptopropionate) (PETMP) with non-self-polymerized precursors, ditosylate poly (ethylene glycol) (DTsPEG) and p-toluenesulfonyl poly (ethylene glycol) methyl ether (TsPEGME), and then blended with a high molecular weight polyethylene oxide (PEO, Mw ​= ​300 ​kg ​mol−1). The resulting self-standing membrane achieves an excellent ionic conductivity (1.3 ​× ​10−4 ​S ​cm−1) at ambient temperature, and exhibits an electrochemical stability window up to 4.3 ​V vs. Li/Li+. The LiFePO4/semi-IPN-SPE/Li battery exhibits a first discharging capacity of 143.1 ​mA ​h ​g−1 ​at 0.2C and the discharge capacity keeps 134 ​mA ​h ​g−1 after 100 charge and discharge cycles.

A Potential Approach to Enhance the Seebeck Coefficient of UHMWPE by Using the Graphene Oxide

Thermoelectric materials have been a competent source for the production of energy in the present decade. The most important and potential parameter required for the material to have better thermoelectric characteristics is the Seebeck coefficient. In this work, ultra high molecular weight polyethylene (UHMWPE) and graphene oxide (GO) nanocomposites were prepared by mechanical mixing by containing 10000ppm, 50000ppm, 70000ppm, 100000ppm, 150000ppm, and 200000ppm loadings of graphene oxide. Due to the intrinsic insulating nature of UHMWPE, the value of Seebeck for pristine UHMWPE and its nanocomposites with 10000ppm & 50000ppm of GO concentration was too low to be detected. However, the Seebeck coefficient for composites with 70000ppm, 100000ppm, 150000ppm, and 200000ppm loadings of GO was found to be 180, 206, 230, and 235 µV/ K, respectively. These higher values of Seebeck coefficients were attributed to the superior thermal insulating nature of UHMWPE and the conductive network induced by the GO within the UHMWPE insulating matrix. Although, the values of the figure of merit and power factor were negligibly small due to the lower concentration of charge carriers in UHMWPE/ GO nanocomposites but still reported, results are extremely hopeful for considering the composite as the potential candidate for thermoelectric applications.

Novel Bulky Lithium Salts and Their Electrolytes for Safer Solid-State Lithium Metal Battery

In recent years, Lithium metal batteries (LMBs) have gained great interests thanks to their high capacity that can respond to the continuous increasing need for energy storage and device. The design and development of new solid-state electrolytes e.g. polymer based ones (SPEs) then became crucial towards intrinsically safer LMBs. A successful electrolyte candidate needs to fulfill several requirements such as high transference number (tLi +) and a compromise between two antagonist properties: conductivity and mechanical properties. Most researches focused on the synthesis of single-ion conducting electrolytes as a strategy to overcome these difficulties1,2. However, these materials often require complicated and delicate chemistry and their conductivity often remains low (σ < 10-5 S/cm at 60°C). An alternative promising route that received much less attention is the development of bulky Lithium salts with macroanion. The bulky anion reduces ion paring and salts aggregation and present negligible mobility compared to Lithium cation resulting in higher transference number3.In this work, we present a new macroanion based on Polyhedral Oligomeric Silsesquioxane (POSS) grafted with either polyethylene oxide oligomers (PEG) and/or Lithium sulfonyl (trifluoromethanesulfonyl) imide (LiTFSI) denoted as POSS-LiTFSI-PEG or POSS-LiTFSI respectively. Thus, SPE has been prepared with a reference high molecular weight polyethylene oxide at different OE/Li ratio from 10 to 25. This new concept of bulky multi-anion based on TFSI moieties allows a complete salt dissociation, an enhancement of the mechanical properties thanks to the presence of the inorganic POSS multi anions that play the role of nano fillers, and finally, a strong increase of the Li+ transference number (tLi+>0,55), which opens many perspectives. The cycling performance obtained in both Lithium symmetric cells and LMBs prototypes will be also presented.References(1) Bouchet, R.; Maria, S.; Meziane, R.; Aboulaich, A.; Lienafa, L.; Bonnet, J.-P. P.; Phan, T. N. T.; Bertin, D.; Gigmes, D.; Devaux, D.; et al. Single-Ion BAB Triblock Copolymers as Highly Efficient Electrolytes for Lithium-Metal Batteries. Nat. Mater. 2013, 12 (5), 452–457.(2) Zhang, H.; Li, C.; Piszcz, M.; Coya, E.; Rojo, T.; Rodriguez-Martinez, L. M.; Armand, M.; Zhou, Z. Single Lithium-Ion Conducting Solid Polymer Electrolytes: Advances and Perspectives. Chem. Soc. Rev. 2017, 46 (3), 797–815.(3) Chinnam, P. R.; Wunder, S. L. Polyoctahedral Silsesquioxane-Nanoparticle Electrolytes for Lithium Batteries: POSS-Lithium Salts and POSS-PEGs. Chem. Mater. 2011, 23 (23), 5111–5121. Figure 1

Extended release pellets prepared by hot melt extrusion technique for abuse deterrent potential: Category-1 in-vitro evaluation.

The objective of the present study was to develop extended-release (ER) hot-melt extruded (HME) abuse-deterrent pellets of acetaminophen, a model drug, by utilizing high molecular weight polyethylene oxide (PEO) and gelling agents (xanthan gum, guar gum, and gellan gum). The HME pellets were evaluated for their abuse-deterrence (AD) potential by Category-1 laboratory in-vitro evaluation parameters, including particle size reduction (PSR), small volume extraction, dissolution, viscosity, syringeability, and injectability. Further, the pellets were investigated for resistance to physical (crushing) and thermal (oven and microwave) manipulation to evaluate the strength of the AD properties. Physical manipulation studies demonstrated that the pellets were intact, extremely hard, and resistant to PSR and manipulation to bypass ER properties. Dissolution of all intact and physically manipulated pellets led to complete drug release within 8h, and resistance to dose-dumping in 40% ethanol was observed. The drug extraction was <50% in 10mL of ingestible and non-ingestible solvents under static, agitation, and thermal manipulation conditions with an incubation time of 30min. The PEO/xanthan gum-based formulation showed higher viscosity, syringe and injection forces, and lower syringeable volume in all manipulation conditions compared with plain PEO pellets. These findings supported the AD potential of PEO and xanthan gum pellets against intravenous abuse.

Polyethylene Oxide Molecular Size Determines the Severity of Atypical Thrombotic Microangiopathy in a Guinea Pig Model of Acute Intravenous Exposure.

In 2017, Opana ER was voluntarily removed from the U.S. market based on concerns that its risks outweighed its therapeutic benefits. The data that supported this conclusion were based on postmarketing evaluation that demonstrated increased intravenous abuse associated outbreaks of HIV, hepatitis C, and uniquely, a thrombotic thrombocytopenic purpura (TTP)-like syndrome. In 2017, the cause was mechanistically linked to intravenous exposure of the high-molecular weight polyethylene oxide (PEO), an excipient component of the drug product. However, it was unknown how differing PEO preparations might alter this response in vivo. Knowing the likelihood of a PEO driven atypical thrombotic microangiopathy with hemolytic uremic syndrome (TMA-HUS), this study was specifically designed with the primary objective focused on understanding the impact of PEO molecular weight on TMA-HUS in a guinea pig model of acute repeat PEO (1, 4, and 7 MDa) dosing. Results from this analysis suggest that repeated dosing with PEO 4 and 7 MDa, but not 1 MDa induced a marked intravascular hemolysis with schistocytes, mild anemia, thrombocytopenia, hemoglobinuria, and kidney injury, consistent with observations of a TMA-HUS-like syndrome. Nonetheless, observations of tissue microthrombi, complement or altered von Willebrand factor involvement were not observed, which would be consistent with a definitive TMA. Further, only 7 MDa PEO dosing was associated with marked renal hypoxia. Taken together, this study defines renal injury risk with PEO formulations >1 MDa that is driven by a robust intravascular hemolysis and potentially, tissue hypoxia.

Semiconducting Small Molecules as Active Materials for p‐Type Accumulation Mode Organic Electrochemical Transistors

AbstractA series of semiconducting small molecules with bithiophene or bis‐3,4‐ethylenedioxythiophene cores are designed and synthesized. The molecules display stable reversible oxidation in solution and can be reversibly oxidized in the solid state with aqueous electrolyte when functionalized with polar triethylene glycol side chains. Evidence of promising ion injection properties observed with cyclic voltammetry is complemented by strong electrochromism probed by spectroelectrochemistry. Blending these molecules with high molecular weight polyethylene oxide (PEO) is found to improve both ion injection and thin film stability. The molecules and their corresponding PEO blends are investigated as active layers in organic electrochemical transistors (OECTs). For the most promising molecule:polymer blend (P4E4:PEO), p‐type accumulation mode OECTs with µA drain currents, μS peak transconductances, and a µC* figure‐of‐merit value of 0.81 F V−1 cm−1 s−1 are obtained.

Polyethylene Oxide (PEO) Molecular Weight Effects on Abuse-Deterrent Properties of Matrix Tablets.

While polyethylene oxide (PEO)-based matrix tablets are frequently used as abuse-deterrent dosage forms, there is limited information available regarding how the selection of formulation components and manufacturing processes affect the resulting abuse-deterrent properties. The objective of the current study was to evaluate the effects of formulation and process variables on the abuse-deterrent features of PEO-containing tablets. Directly compressed tablets were prepared using three different PEO molecular weights (100,000; 900,000; and 5,000,000). As anticipated, sintering/thermal treatment above the melting point of PEO was crucial to impart crush-resistant features (tablet hardness > 500N). In addition to the sintering temperature, the weight fraction of PEO in the tablets affected their mechanical strength, and at least 50% w/w PEO was required to impart the desired crush-resistant features. In addition, the formulation and process variables also impacted syringeability and injectability of the PEO gels formed when the tablets were hydrated to simulate attempted drug extraction. High molecular weight PEO (900,000 and 5,000,000) produced gels more resistant to syringeability and injectability compared to low molecular weight PEO (100,000). Sintering above the polymer melting point decreased PEO crystallinity after cooling, and longer sintering times resulted in PEO degradation producing lower viscosity gels with reduced resistance to syringeability and injectability. Although sintering above the melting point of PEO imparts optimal mechanical strength to the tablets, prolonged sintering durations negatively impact polymer stability and alter the resulting abuse-deterrent features of the PEO-based tablet formulations.

Semi‐Interpenetrating Network‐Structured Single‐Ion Conduction Polymer Electrolyte for Lithium‐Ion Batteries

AbstractA novel quasi solid single‐ion polymer electrolyte with semi‐interpenetrating network (semi‐IPN) structure has been prepared. The lithium‐ion conduction membrane is composed of both the cross‐linked lithiated poly‐2‐acrylamido‐2‐methylpropane sulfonic acid (PAMPS‐Li) as a polyanionic single‐ion lithium salt source and the high molecular weight polyethylene oxide (PEO) as a polymer matrix, in which the two components show great compatibility due to the special semi‐IPN structure. For such quasi‐solid electrolyte system, we have particularly studied the crystallinity variety and ionic conductivity change with a series of polymer salt concentration. The results show that the electrolyte has an appropriate mechanical stability, minimal crystallinity, and acceptable ionic conductivity of 1.34×10−5 S/cm at 60 °C. Furthermore, the lithium‐ion conduction membrane shows the lithium‐ion dominating conductive property and high transport number of 0.77. Moreover, the LiFePO4/Li batteries’ cycle results show a high discharge capacity of 140.0 mAh/g and a retention of 90.4 % after 100 cycles at the rate of 0.2 C.

THE IMPROVEMENT OF THE TECHNOLOGICAL SCHEME OF PRODUCTION OF STABILIZED AND PROCESSED CATALYST OF THE MEDIUM-TEMPERATURE CONVERSION OF OXIDE CARBON

The article deals with the possibility of reducing the environmental burden on the environment, for example, by introducing changes in the technological scheme for the production of a stabilized and reformed catalyst for the average temperature conversion of carbon monoxide by steam (STC) from the waste of titanium (IV) oxide production with a low mass fraction of sulfur. The rational conditions of processes of sedimentation, aging, washing and thermal decomposition are proposed, and it allows to reduce the cost price of the target product by eliminating from the technological process the desulfurization stage. The possibility of stabilizing the STK catalyst with hydroxide has been proved. It was determined that the use of samples with ω [Ca (OH) 2] ~ 0.75 mass. % completely eliminates the stage of their desulphurization, since the maximum concentration of H2S in the gas phase at the exit from the reactor was meager at an industrial scale of 0.04 mg / m3. The activity of the obtained samples of the catalyst STK for the constant of the rate of reaction of CO conversion with water vapor at 350 ° C, which averages 2.15 cm3 / (g ∙ s), corresponds to the current level of activity of existing catalysts STK. It has been established that the use of co-precipitation of all catalyst components differs favorably from the prevailing separation deposition. And with the addition of a flocculant based on [(-CH2CHCONH2-) n] polyacrylamide and a high molecular weight polyethylene oxide [(-OSH2CH2-) n], in comparison with the simple process of settling, the sedimentation rate increases 3 ÷ 6 times depending on the concentration of the flocculant. This solution allows to obtain a catalyst with increased activity and thermal stability. In this case, the use of chromium (III) sulphate instead of chrome (VI) oxide can facilitate and improve the efficiency of co-precipitation of catalyst components STK. It was established that the introduction of changes in the technological scheme of production, contributes to reducing energy costs and improving the state of environmental safety.

Micro-machining with abrasive slurry-jets: effects of dissolved polymer concentration and nozzle design

The resolution of features machined with abrasive slurry jets is dependent on the diameter of the erosion footprint on the workpiece and on the stability of the jet. Previous work has shown that the footprint size decreases, but the jet oscillation increases, with increasing polymer concentration. The present study investigated the effect of nozzle design on jet stability in abrasive slurry-jet micro-machining of glass using slurries with dissolved polymers. A variety of transparent acrylic nozzles were made with different geometries and a 180-μm sapphire orifice to study the oscillation of jets of water mixed with high molecular-weight polyethylene oxide. Fluorescent streak photography of the flows within the nozzles confirmed the presence of unstable vortices that can lead to jet oscillation. However, the dependence of these vortices on nozzle geometry and PEO concentration was unclear. Jet oscillation was then measured photographically and found to increase nonlinearly with polymer concentration for all nozzle geometries. These results were used to design and manufacture a new steel nozzle with a 30° tapered entrance region which reduced jet oscillation. Micro-channels were then machined in glass plates using a range of polymer slurries containing aluminium oxide particles. The polymer concentration that produced the best combination of a relatively small footprint while simultaneously minimizing the jet oscillation amplitude resulted in channels that were 11% narrower than reference channels machined with a pure water slurry and a standard nozzle.