Dry Polymer Research Articles

Modeling Experimental Parameters for the Fabrication of Multifunctional Surfaces Composed of Electrospun PCL/ZnO-NPs Nanofibers.

In this work, a one-step electrospinning technique has been implemented for the design and development of functional surfaces with a desired morphology in terms of wettability and corrosion resistance by using polycaprolactone (PCL) and zinc oxide nanoparticles (ZnO NPs). The surface morphology has been characterized by confocal microscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM) and water contact angle (WCA), whereas the corrosion resistance has been evaluated by Tafel polarization curves. Strict control over the input operational parameters (applied voltage, feeding rate, distance tip to collector), PCL solution concentration and amount of ZnO NPs have been analyzed in depth by showing their key role in the final surface properties. With this goal in mind, a design of experiment (DoE) has been performed in order to evaluate the optimal coating morphology in terms of fiber diameter, surface roughness (Ra), water contact angle (WCA) and corrosion rate. It has been demonstrated that the solution concentration has a significant effect on the resultant electrospun structure obtained on the collector with the formation of beaded fibers with a higher WCA value in comparison with uniform bead-free fibers (dry polymer deposition or fiber-merging aspect). In addition, the presence of ZnO NPs distributed within the electrospun fibers also plays a key role in corrosion resistance, although it also leads to a decrease in the WCA. Finally, this is the first time that an exhaustive analysis by using DoE has been evaluated for PCL/ZnO electrospun fibers with the aim to optimize the surface morphology with the better performance in terms of corrosion resistance and wettability.

On Site Improvement of Fines-Rich Unbound Granular Materials with Hydrophobic Polymer and Lime

Many roads that were initially designed for relatively low traffic volumes need re-surfacing or partial replacement of the unbound granular material to satisfy current traffic demand. Significant research efforts based on laboratory studies have been seen in the literature to characterize the suitability of virgin materials, which is relatively expensive and unsustainable. Therefore, the object of this study is the in situ recycling of existing materials in two road sections by improving their properties with a suitable additive. A hydrophobic synthetic polymer was chosen for two trials due to the high plasticity of fines of the in situ materials and a high chance of water intrusion in the low-lying plains in Adelaide. The extensive laboratory characterization shows that hydrophobicity is imparted in capillary rise tests, improved drainage in permeability tests, and greater matric suction at the same moisture content. Furthermore, the unconfined compressive strength was increased. The repeated loading triaxial testing showed higher stiffness and lowered permanent strain to withstand higher traffic volume. In general, in situ recycling is adaptable and considered to be cheaper and sustainable. The estimated current costs and carbon footprints are presented for re-construction and in situ recycling with dry powder polymer, or solely with lime, to help construction planning.

Implementation of nanopolymer systems for reducing production watercut

The paper deals with the industrial experiment works carried out in Kazakhstan on the injection of pseudoplastic polymer nanosystem for reducing production watercut in the oil field with high viscous oil with 80-90 % watercut and low oil recovery rate. The estimation of efficiency justified that during ten months after industrial experiment works conducted, technological effect was more than 100 t of oil for 1 t of injected dry polymer, and the increase of oil recovery rate was 2 % while watercut decreased for 20 %.

A New Recipe for Friction-Reducer Suppliers: Polymer Plus Frac Water, Minus the Cost

The argument for making friction reducer on site is simple: only one truck is required to deliver dry polymer vs. three loads required for the same amount of liquid additive. For Downhole Chemical Solutions (DCS), reducing the number of trips and the amount of chemicals needed to create a stable liquid by mixing it as needed on site reduces the average cost of a gallon of friction reducer by around 30%, said Mark Van Domelen, vice president of technology for DCS. “The business is very cutthroat and competitive on the pricing of polyacrylamide. We can reduce the cost further on friction reducer,” using dry polymer, he said. Polyacrylamide is generally described as the key component in friction reducers. Suppliers also add some ingredients to create a stable liquid and others that are supposed to improve performance. When DCS delivers dry polymer to a well pad to mix it on-site, the only other ingredient is water provided by the customer. It has been a winning strategy change for the private company; it has grown rapidly, even during last year’s slump. DCS increased the number of mixing units from one to 16, and dry polymer sales have grown from 10% to 90%, Van Domelen said. One of the company’s customers is John Blevins, the chief operating officer for Houston-based Hibernia Resources III and an early adopter who was a lead author of a paper on making friction reducer on site while fracturing (SPE 204176). Blevin, who uses the words “friction reducer” and “polymer” interchangeably, is the rare C-level executive who likes to manage operations from a frac van at a company that normally completes one pad at a time. The polymer is polyacrylamide. When Blevin works with DCS on a well, he purchases it directly from one of the few chemical companies that will produce the polymer based on his specifications. The price on the DCS invoice will be a price per pound that covers the cost of the polymer and the service. At Hibernia, a small private-equity and employee-owned company, there is a powerful incentive to pay close attention to the details. “When we spend a nickel, that nickel is divided among us at some point in time. If we are efficiently frugal, we are going to be better off in the long run,” Blevins said. The paper, which was presented at the Unconventional Resources Technology Conference (URTeC), included a chart showing stage-by-stage costs, with the average cost for dry stages ranging from 27% to 31% lower than similar stages that were fractured using liquids. The simplicity of the mix is a plus for Blevins whose company is especially focused on how chemicals are likely to react downhole. “We did a 6-month study before we pumped anything in the ground to make sure we had the right combination” of fracturing additives, he said. “We do study nearly every well and every landing zone to ensure the chemicals used are compatible.”

Dry Polymer Electrolyte Concepts for Solid‐State Batteries

AbstractDry polymer electrolytes are a promising class of materials for future safer high‐energy‐density battery technologies. This review deals with the relevant physico‐chemical properties of the dry polymer electrolytes, ionic transport mechanism, molecular structure, and interfacial issues in a widely investigated model system (poly(ethylene oxide) with lithium bis(trifluoromethanesulfonyl)imide). At the end of the review, latest macromolecular approaches for high‐performance lithium battery applications are discussed.

Theoretically Self-Consistent Nonequilibrium Thermodynamics of Glassy Polymer Theory for the Solubility of Vapors and Liquids in Glassy Polymers

The nonequilibrium thermodynamics of glassy polymer (NETGP) theory provides a formalism to calculate solubilities of volatile species in glassy polymers using equilibrium free energies. The classic NETGP approach of Sarti and Doghieri assumes that the glassy polymer density of a solvent swollen polymer is known a priori. In the modified approach developed in this work, this density is calculated self-consistently. The self-consistent calculation of the swollen polymer density has profound implications on both the theoretical and practical aspects of the theory. This is accomplished by means of a new class of perturbation theory, which assumes that the sorption of volatile species in a glassy polymer can be treated as a perturbation to a dry polymer reference state. The new approach is then validated against sorption data in several glassy polymers.

Boric acid removal with polyol-functionalized polyether membranes

Poor selectivity of conventional desalination membranes for boron often necessitates multi-stage treatment trains to achieve desired boron removal for end uses such as irrigation. One approach to membrane design for improved single-pass boric acid removal is via incorporation of chelating ligands that selectively sorb boron. In this study, membranes based on epoxy-amine cross-linked poly(glycidyl glycidyl ether) (PGGE) were synthesized and functionalized with N-methyl-d-glucamine (NMDG), a polyol known to interact selectively with boron. PGGE and PGGE-NMDG membranes exhibited boron sorption isotherms that were well-described by dual mode isotherms. PGGE-NMDG sorbed 2.5 mmol B/g dry polymer from a neutral aqueous solution containing 100 mmol B/L, which was almost three times the adsorption density of a commercial boron selective resin, Amberlite IRA743. The membranes were regenerated in acid without a significant loss of boron sorption capacity over four cycles. Interactions between boron and NMDG and PGGE sites (e.g., epoxides) impacted boron diffusion in both membranes. The use of ligand functionalized membranes to capture target solutes such as boron requires high loading of interacting sites to maximize uptake capacity. Establishing fundamental structure/property rules for boron selectivity could lead to new material designs with improved boron separation properties for water purification.

Neutron investigation of interaction between anionic surfactant micelles and poly (ethylene glycol) polymer brush system

A polymer brush system of a neutral polymer poly (ethylene glycol) with a molecular weight of Mw = 20 kDa on silicon substrates in an aqueous medium was studied by the specular neutron reflectometry. Structural changes in the density profile of a polymer brush caused by the interaction of polymer chains with micelles of the anionic surfactant dodecylbenzenesulfonate acid were observed. The effect is shown to be related to the formation of molecular polymer-micelle associates in the bulk of the solution, which was previously studied by small-angle neutron scattering in a wide range of surfactant concentrations at various molecular weights of the polymer. The density of the dry polymer layer on the silicon substrate was additionally characterized by X-ray reflectometry and scanning atomic force microscopy.

Electrochemical Assessment of Indigo Carmine Dye in Lithium Metal Polymer Technology.

Lithium metal batteries are inspiring renewed interest in the battery community because the most advanced designs of Li-ion batteries could be on the verge of reaching their theoretical specific energy density values. Among the investigated alternative technologies for electrochemical storage, the all-solid-state Li battery concept based on the implementation of dry solid polymer electrolytes appears as a mature technology not only to power full electric vehicles but also to provide solutions for stationary storage applications. With an effective marketing started in 2011, BlueSolutions keeps developing further the so-called lithium metal polymer batteries based on this technology. The present study reports the electrochemical performance of such Li metal batteries involving indigo carmine, a cheap and renewable electroactive non-soluble organic salt, at the positive electrode. Our results demonstrate that this active material was able to reversibly insert two Li at an average potential of ≈2.4 V vs. Li+/Li with however, a relatively poor stability upon cycling. Post-mortem analyses revealed the poisoning of the Li electrode by Na upon ion exchange reaction between the Na countercations of indigo carmine and the conducting salt. The use of thinner positive electrodes led to much better capacity retention while enabling the identification of two successive one-electron plateaus.

A New Approach for Thermal Resistance Prediction of Different Composition Plain Socks in Wet State (Part 2)

Abstract Socks’ comfort has vast implications in our everyday living. This importance increased when we have undergone an effort of low or high activity. It causes the perspiration of our bodies at different rates. In this study, plain socks with different fiber composition were wetted to a saturated level. Then after successive intervals of conditioning, these socks are characterized by thermal resistance in wet state at different moisture levels. Theoretical thermal resistance is predicted using combined filling coefficients and thermal conductivity of wet polymers instead of dry polymer (fiber) in different models. By this modification, these mathematical models can predict thermal resistance at different moisture levels. Furthermore, predicted thermal resistance has reason able correlation with experimental results in both dry (laboratory conditions moisture) and wet states.

Multiscale Friction Simulation of Dry Polymer Contacts: Reaching Experimental Length Scales by Coupling Molecular Dynamics and Contact Mechanics

This work elucidates friction in Poly-Ether-Ether-Ketone (PEEK) sliding contacts through multiscale simulations. At the nanoscale, non-reactive classical molecular dynamics (MD) simulations of dry and water-lubricated amorphous PEEK–PEEK interfaces are performed. During a short running-in phase, we observe structural transformations at the sliding interface that result in flattening of the initial nanotopographies accompanied by strong polymer chain alignment in the shearing direction. The MD simulations also reveal a linear pressure – shear stress dependence and large adhesive friction in dry conditions. This dependence, summarized in a nanoscale friction law, is of central importance for our multiscale approach, since it forms a link between MD and elastoplastic contact mechanics calculations. An integration of the nanoscale friction law over the real area of contact yields a macroscopic friction coefficient that allows for a meaningful comparison with measurements from macroscopic tribometer experiments. Severe normal loading conditions result in significant wear and high experimental friction coefficients µ≈0.5–0.7, which are in good agreement with the calculated values from the multiscale approach in dry conditions. For milder experimental loads, our multiscale model suggests that lower friction states with µ≈0.2 originate in the presence of physisorbed molecules (e.g., water), which significantly reduce interfacial adhesion.

Machine Learning Solvation Environments in Conductive Polymers: Application to ProDOT-2Hex with Solvent Swelling

Automated identification and classification of ion solvation sites in diverse chemical systems will improve the understanding and design of polymer electrolytes for battery applications. We introduce a machine learning approach to classify and characterize ion solvation environments based on feature vectors extracted from all-atom simulations. This approach is demonstrated in poly(3,4-propylenedioxythiophene), which is a promising candidate polymer binder for Li-ion batteries. In the dry polymer, four distinct Li⁺ solvation environments are identified close to the backbone of the polymer. Upon swelling of the polymer with propylene carbonate solvent, the nature of Li⁺ solvation changes dramatically, featuring a rapid diversification of solvation environments. This application of machine learning can be generalized to other polymer condensed-phase systems to elucidate the molecular mechanisms underlying ion solvation.

Tailoring Slurries Using Cosolvents and Li Salt Targeting Practical All‐Solid‐State Batteries Employing Sulfide Solid Electrolytes

AbstractPolymeric binders that can undergo slurry fabrication and minimize the disruption of interfacial Li+ contact are imperative for sheet‐type electrodes and solid electrolyte films in practical all‐solid‐state Li batteries (ASLBs). Although dry polymer electrolytes (DPEs) are a plausible alternative, their use is complicated by the severe reactivity of sulfide solid electrolytes and the need to dissolve Li salts. In this study, a new scalable fabrication protocol for a Li+‐conductive DPE‐type binder, nitrile‐butadiene rubber (NBR)‐LiTFSI, is reported. The less‐polar dibromomethane and more‐polar hexyl butyrate in cosolvents work synergistically to dissolve NBR and LiTFSI, while preserving Li6PS5Cl0.5Br0.5. It is found that the dispersion of NBR can be controlled by the fraction of the antisolvent (hexyl butyrate), which in turn affects the corresponding performance of the ASLBs. Sheet‐type LiNi0.70Co0.15Mn0.15O2 electrodes tailored using NBR‐LiTFSI outperform those prepared using the conventional insulating binder (NBR) in terms of capacity (163 vs 147 mA h g−1) and initial Coulombic efficiency (78.9 vs 70.4%), which is attributed to the facilitated interfacial Li+ transport, as confirmed by 6Li nuclear magnetic resonance and electrochemical measurements. Moreover, NBR‐LiTFSI is functional at 70 °C and in a graphite anode. Finally, the promising performance of pouch‐type LiNi0.70Co0.15Mn0.15O2/graphite ASLBs is also demonstrated.

Tactical hybrids of Li+-conductive dry polymer electrolytes with sulfide solid electrolytes: Toward practical all-solid-state batteries with wider temperature operability

The chemical vulnerability of sulfide solid electrolyte (SE) materials to organic polar solvents complicates the wet-slurry fabrication of sheet-type electrodes and SE films for practical all-solid-state Li batteries (ASLBs). Moreover, the disruption of interfacial Li+ conduction by binders is problematic. This could be relieved by blending with liquid electrolytes but at the expense of the ASLBs’ thermal stability. In this study, a new tactical approach to hybridize sulfide SEs with thermally stable and slurry-fabricable dry polymer electrolyte (DPE)-type binders is reported. Along with their practicability, ester solvents bearing bulky hydrocarbons, such as benzyl acetate, dissolve both polymers and Li salts (e.g., LiTFSI) while undamaging sulfide SEs. The use of the DPE-type binder, NA-LiTFSI (NA: nitrile butadiene rubber-poly(1,4-butylene adipate)), for LiNi0.70Co0.15Mn0.15O2 (NCM) electrodes significantly improves their electrochemical performance at 30 °C. Moreover, NA-LiTFSI is highly functional at 70 °C (from 180 to 200 mA h g−1 and from 84.2 to 91.8% for initial Coulombic efficiency) and applicable for other electrodes, such as graphite (from 265 to 330 mA h g−1) and Li4Ti5O12, which is in stark contrast to the solvate ionic liquid-type binder Li(G3)TFSI. Finally, pouch-type NCM/graphite ASLBs employing electrodes made of NA-LiTFSI binders were also fabricated.

One‐step preparation of poly(NIPAM‐pyrrole) electroconductive composite hydrogel and its dielectric properties

AbstractConductive polymers and hydrogels are two of the hot prospect polymer types that are used for new stimuli responsive materials. In this study, one‐step preparation of electroconductive composite hydrogels containing polypyrrole (PPy) and N‐isopropylacrylamide (NIPAM) using free radical polymerization technique was achieved with N,N‐methylenebisacrylamide as a crosslinker and ammonium peroxy disulphate (APS) as initiator, in mixture of water/isopropyl alcohol. The equilibrium swelling degree of the poly(NIPAM)‐pyrrole) electroconductive composite hydrogel was 9.88 g of H2O/g dry polymer. According to TGA results, the thermal stability of the prepared composite poly(NIPAM‐PPy) conductive hydrogel (700°C) hydrogel is higher than that of pure poly(NIPAM) hydrogel (600°C). Furthermore, prepared samples were characterized by FTIR, and SEM analyzes. Later, the samples were pressured into pellets so that electrical impedance spectroscopy (EIS) measurements were taken between 10 and 10 MHz at room temperature. The dielectric constant value of composite poly(NIPAM‐PPy) hydrogel at 10 Hz is almost 10 times higher than that of poly(NIPAM) hydrogel. Both samples' real and imaginary parts of dielectric constant decreased with increased frequency. Samples exhibited non‐Debye relaxation since experimental data fit into dielectric model of Havriliak‐Negami. Moreover, low frequency data yielded d.c. conductivity of the pure and composite samples as 3.74 × 10−11 and 1.02 × 10−8 S/cm, respectively. Real part of impedance at low frequencies also points out ~103 times lower resistance values at 10 Hz for composite poly(NIPAM‐PPy) hydrogel. Therefore, EIS results support that electroconductive composite hydrogel fabrication was achieved using free radical polymerization technique.

Removal of Oil from Oil-in-Water Emulsion by Poly (Sulfur/Soya Bean Oil) Composite Adsorbent: An Equilibrium Study

This work describes synthesis of poly (sulfur/soya bean oil) composite material by co-polymerization of elemental sulfur and soya bean oil at 180 °C. The poly (sulfur/soya bean oil) (PSSBO) composite material was characterized by FTIR, XRD and SEM, BET, and TGA analysis. The surface area was found to be 4.063 m2 per g. The XRD analysis revealed that sulfur also existed as S8 in the polymer matrix also and therefore all the peaks of native elemental S8 were also found in the sample PSSBO (1:1). The SEM analysis indicated multilayered even surface. The PSSBO (1:1) composite was employed in batch mode experiments for the removal of oil from O/W emulsions, prepared in the range of 50 to 400 mg L−1 from Soya bean oil and distilled water. The adsorption data, obtained at 298 K, were interpreted in terms of various isotherm models. Based on the regression values, the order of fitness of these models was Langmuir > Freundlich > Temkin. The maximum oil sorption capacity was found to be 14285.71 mg per g dry polymer. The adsorbent was re-generated by washing with minimum quantity of ethanol and employed in five successive cycles for de-emulsification of water. A hydrophobic–hydrophobic interactions based mechanism was proposed to explain oil uptake by adsorbent PSSBO (1:1) composite. Considering zinc-based zeolitic imidazolate framework (ZIF-8) as a model adsorbent, it was found that Qo value of PSSBO (1:1) was almost three times greater than ZIF-8 and production cost of PSSBO (1:1) was almost 450 times less than ZIF-8.

Numerical investigations of polymer sheet breakup and secondary phase change processes in steam contactors

Polymer devolatilization or steam stripping involves removing any unwanted substances, such as volatiles and solvents, from the polymer mixture. This is achieved via mixing with superheated steam and breakup into smaller droplets followed by phase change, resulting in dry polymer crumb. The objective of the current study is embodied in two steps. The first step involves the development of a computational fluid dynamics (CFD)-based multiphase model that solves for the initial breakup of the liquid polymer mixture by steam. As part of this effort, detailed parametric studies are conducted to determine the effects of different contactor geometries on the initial sheet breakup, and the potential impact on the final polymer product quality. The second step then uses the resulting diameter distribution to model the multiphase heat and mass transfer of the polymer mixture including evaporation of the solvent. Specifically, 3D CFD calculations are carried out using a Eulerian-Lagrangian approach, where the superheated steam is modelled as the continuous phase and tracked in a Eulerian frame, while the cement droplets are treated using a Lagrangian tracking method, thereby providing distributions of particle sizes, temperatures, and solvent content in the contactor. Results can help optimize the devolatilization process in terms of steam savings and volatile content in the final polymer.

Gas Transport Properties of the Metal–Organic Framework (MOF)-Assisted Polymer of Intrinsic Microporosity (PIM-1) Thin-Film Composite Membranes

The current study summarizes the findings of single-gas transport performances of mixed matrix thin-film composite membranes consisting of metal–organic frameworks (MOFs) incorporated into a polymer of intrinsic microporosity (PIM-1). Mg-MOF-74, MIL-53, TIFSIX-3, and Zn2(bim)4 were investigated as stand-alone materials and as incorporated into the PIM-1 polymer matrix serving as a selective layer of thin-film composite membranes by various methods: Fourier-transform infrared spectroscopy, solid-state NMR, X-ray diffraction, thermogravimetric analysis, and scanning electron microscopy. The effect of MOF loading and nature on the mixed-matrix membrane morphology and operation were analyzed by varying the MOF content in the polymer matrix from 2 to 10 wt % with respect to the dry polymer weight. The results show that the incorporation of MOFs into the PIM-1 polymer matrix boosts the permeance and selectivity of H2 and O2 over N2, and the prepared PIM-1/TIFSIX_4 mixed matrix membrane shows better separation performance for CO2/CH4 than pure PIM-1. Such membranes can be good candidates for ammonia purge gas, oxygen enrichment, and acid gas treatment applications.

Hydroxypropyl methylcellulose or soy protein isolate‐based edible, water‐soluble, and antioxidant films for safflower oil packaging

Edible, water-soluble, heat-sealable, and antioxidant films were developed from hydroxypropyl methylcellulose (HPMC) or soy protein isolate (SPI) and applied as safflower oil packaging. A 0.1 or 0.2% DL-α-tocopherol acetate (VE) and 0 or 0.25% oleic acid were added into film formulations to provide antioxidant and hydrophobic properties, respectively, using a 23 factorial design. Films were analyzed for appearance, microstructure, water and oil sensitivity, mechanical properties, and antioxidant functionality. Subsequently, a completely randomized design was implemented for incorporating 2, 4, or 6% cellulose nanocrystals (CNCs, w/w dry weight polymer) for improving film mechanical and barrier properties. HPMC-based films achieved full dissolution in water at <55 °Cunder 5min, while SPI-based films disintegrated in water up to 90 °C. Oleic acid significantly increased (P <0.05) heat sealability of SPI film from 78 to 143N/m and elongation at break from 36% to 88%, but decreased tensile strength and heat sealability of HPMC films by 55% and 41%, respectively. As safflower oil packaging, after 60 days of storage at 35 °C, oil contained in SPI-based pouch had the lowest peroxide values, 8.1 ± 0.9mEq/kg. Based on barrier, mechanical, and antioxidant capacity evaluations, HPMC film with 0.1% VE and SPI film with 0.25% oleic acid and 0.1% VE were incorporated with CNC. SPI/CNC films did not show observable trends, but HPMC/2% CNC film exhibited significantly improved mechanical and barrier properties, with oxygen permeability of 5.0mL mm/m2 day kPa. The developed films are a promising packaging alternative to decrease plastic waste, extend shelf life of lipid-based foods, and increase consumer convenience. PRACTICAL APPLICATION: Individually packaged, single-use pouches of sauce or oil are common for seasoning instant and frozen foods, creating unnecessary plastic waste. Edible, water-soluble packaging with antioxidant functionality would reduce plastic waste, extend shelf life by preventing oxidation, and increase consumer convenience. The biopolymeric films and pouches developed in this study have unique properties from water solubility across a wide range of temperatures, resistance to oil, high oxygen barrier, and good heat sealability, providing a variety of potential applications for promoting sustainable food packaging.

Approximate solution techniques for the sorption of a finite amount of swelling solvent in a glassy polymer

This study examines a one-dimensional Stefan problem describing the sorption of a finite amount of swelling solvent in a glassy polymer. The polymer is initially in a dry non-swollen state, where the polymer network is dense. The polymer is then injected with a critical concentration of a swelling solvent, causing polymer chain relaxation to occur. A moving boundary separating the swollen rubbery polymer from the dry glassy polymer is created, whose speed is defined by a kinetic law. The form of the kinetic law is typically assumed to be linear, but this is a nonphysical restriction, and thus we consider the case for a general exponent. We present formal asymptotic expansions, for both small and large times as well as for small and large values of the control parameter, as well as considering the heat balance integral method. These approximations are compared with a numerical scheme, which uses a boundary immobilisation technique and correctly identifies the appropriate starting solution.