Influence of polymer additives on turbulent energy cascading in forced homogeneous isotropic turbulence studied by direct numerical simulations

Direct numerical simulations （DNS） were performed for the forced homogeneous isotropic turbulence （FHIT） with/without polymer additives in order to elaborate the characteristics of the turbulent energy cascading influenced by drag-reducing effects. The finite elastic non-linear extensibility-Peterlin model （FENE-P） was used as the conformation tensor equation for the viscoelastic polymer solution. Detailed analyses of DNS data were carried out in this paper for the turbulence scaling law and the topological dynamics of FHIT as well as the important turbulent parameters, including turbulent kinetic energy spectra, enstrophy and strain, velocity structure function, small-scale intermittency, etc. A natural and straightforward definition for the drag reduction rate was also proposed for the drag-reducing FHIT based on the decrease degree of the turbulent kinetic energy. It was found that the turbulent energy cascading in the FHIT was greatly modified by the drag-reducing polymer additives. The enstrophy and the strain fields in the FH1T of the polymer solution were remarkably weakened as compared with their Newtonian counterparts. The small-scale vortices and the small-scale intermittency were all inhibited by the viscoelastic effects in the FHIT of the polymer solution. However, the scaling law in a fashion of extended self-similarity for the FHIT of the polymer solution, within the presently simulated range of Weissenberg numbers, had no distinct differences compared with that of the Newtonian fluid case.

Functional additives for solid polymer electrolytes in flexible and high-energy-density solid-state lithium-ion batteries

Solid polymer electrolytes(SPEs)have become increasingly attractive in solid-state lithium-ion batteries(SSLIBs)in recent years because of their inherent properties of flexibility,processability,and interfacial compatibility.However,the commercialization of SPEs remains challenging for flexible and high-energy-density LIBs.The incorporation of functional additives into SPEs could significantly improve the electrochemical and mechanical properties of SPEs and has created some historical milestones in boosting the development of SPEs.In this study,we review the roles of additives in SPEs,highlighting the working mechanisms and functionalities of the additives.The additives could afford significant advantages in boosting ionic conductivity,increasing ion transference number,improving high-voltage stability,enhancing mechanical strength,inhibiting lithium dendrite,and reducing flammability.Moreover,the application of functional additives in high-voltage cathodes,lithium-sulfur batteries,and flexible lithiumion batteries is summarized.Finally,future research perspectives are proposed to overcome the unresolved technical hurdles and critical issues in additives of SPEs,such as facile fabrication process,interfacial compatibility,investigation of the working mechanism,and special functionalities.

Modified Vegetable Oil Based Additives as a Future Polymeric Material—Review

Polymeric materials from renewable resources have attracted a lot of attention in recent years. The development and utilization of vegetable oils for polymeric materials are currently in the spotlight of the polymer and chemical industry, as they are the largest renewable platform due to their universal wide availability, ingrained biodegradability, low cost, and excellent environmental aspects (i.e., low ecotoxicity and low toxicity toward humans). These excellent natural characteristics are now being taken advantage of in research and development, with vegetable oil derived polymers/polymeric materials/composites being used in numerous applications including paints and coatings, adhesives, and nanocomposites. The aim of this review paper is to give a fundamental description of the various vegetable oil applications in polymer materials and its recent developments. Particular emphasis will be placed on study and main application of triglyceride based additive for polymer and to give the reader an insight into the main developments is discussed.

TRPIV measurement of turbulent coherent structures in a drag-reducing flow by polymers

Fully developed turbulent flow fields with and without polymer solution at the same Reynolds number were measured by time-resolved particle image velocimetry （TRPIV） in a water channel to investigate the mechanism of drag-reducing solution from the view of coherent structures manipulation. The streamwise mean velocity and Reynolds stress profiles in the solution were compared with those in water. After adding the polymer solution, the Reynolds stress in the near-wall area decreases significantly. The result relates tightly to the decease of the coherent structures＇ bursting. The spatial topology of coherent structures during bursts has been extracted by the new mu-level criterion based on locally averaged velocity structure function. The effect of polymers on turbulent coherent structures mainly reflects in the intensity, not in the shape. In the solution, it is by suppressing the coherent structures that the wall friction is reduced.

Large-eddy simulations of a forced homogeneous isotropic turbulence with polymer additives

Large-eddy simulations （LES） based on the temporal approximate deconvolution model were performed for a forced homogeneous isotropic turbulence （FHIT） with polymer additives at moderate Taylor Reynolds number. Finitely extensible nonlinear elastic in the Peterlin approximation model was adopted as the constitutive equation for the filtered conformation tensor of the polymer molecules. The LES results were verified through comparisons with the direct numerical simulation results. Using the LES database of the FHIT in the Newtonian fluid and the polymer solution flows, the polymer effects on some important parameters such as strain, vorticity, drag reduction, and so forth were studied. By extracting the vortex structures and exploring the flatness factor through a high-order correlation function of velocity derivative and wavelet analysis, it can be found that the small-scale vortex structures and small-scale intermittency in the FHIT are all inhibited due to the existence of the polymers. The extended self-similarity scaling law in the polymer solution flow shows no apparent difference from that in the Newtonian fluid flow at the currently simulated ranges of Reynolds and Weissenberg numbers.

Drag reduction of flow boiling with polymer additives

The drag reducing effect of polymer additive aqueous solution was investigated in flow boiling, and the polymer additives were two kinds of polyacrylamide (PAM) with relative molecular mass about 2.56×10 6 and 8.55×10 6. The frictional pressure drop was calculated according to the measured total pressure drop. The results show that the flow drag of flow boiling is reduced by adding a small amount of PAM to water when heat flux is in the range of 15.1 kW·m -2 to 47.0 kW·m -2 , when the mass fraction of PAM is higher than 2.0×10 -5 , the drag reducing effect is obvious. Drag reducing effect of PAM, whose relative molecular mass is 8.55×10 6, is slightly better than that of 2.56×10 6 at the same mass fraction, and the greater the flow rate of the additive solution, the better the effect of the drag reduction.

Screening of Polymer Additives in Drinking Water Stored in PET Bottles by UHPLC-ESI-IT-TOF MS

In this study, Ultra High Performance Electrospray Ionization Ion Trap Time of Flight Mass Spectrometry （UHPLC-ESI-1T-TOF MS） method is used to screen the polymer additives in drinking water that is stored in Polyethylene Terephthalate （PET） bottles. After directly analyzing the commercially available water samples, 3 polymer additives （chimassorb 81, irgafos 168 and oleamide） were detected. However, after exposure to sunshine for 8 days, two additional polymer additives （antioxidant 2246 and Butylated Hydroxytoluene （BHT）） were detected besides the former three additives.

Synthetic polymers:A review of applications in drilling fluids

With the growth of deep drilling and the complexity of the well profile,the requirements for a more complete and efficient exploitation of productive formations increase,which increases the risk of various complications.Currently,reagents based on modified natural polymers(which are naturally occurring compounds)and synthetic polymers(SPs)which are polymeric compounds created industrially,are widely used to prevent emerging complications in the drilling process.However,compared to modified natural polymers,SPs form a family of high-molecular-weight compounds that are fully synthesized by undergoing chemical polymerization reactions.SPs provide substantial flexibility in their design.Moreover,their size and chemical composition can be adjusted to provide properties for nearly all the functional objectives of drilling fluids.They can be classified based on chemical ingredients,type of reaction,and their responses to heating.However,some of SPs,due to their structural characteristics,have a high cost,a poor temperature and salt resistance in drilling fluids,and degradation begins when the temperature reaches 130℃.These drawbacks prevent SP use in some medium and deep wells.Thus,this review addresses the historical development,the characteristics,manufacturing methods,classification,and the applications of SPs in drilling fluids.The contributions of SPs as additives to drilling fluids to enhance rheology,filtrate generation,carrying of cuttings,fluid lubricity,and clay/shale stability are explained in detail.The mechanisms,impacts,and advances achieved when SPs are added to drilling fluids are also described.The typical challenges encountered by SPs when deployed in drilling fluids and their advantages and drawbacks are also discussed.Economic issues also impact the applications of SPs in drilling fluids.Consequently,the cost of the most relevant SPs,and the monomers used in their synthesis,are assessed.Environmental impacts of SPs when deployed in drilling fluids,and their manufacturing processes are identified,together with advances in SP-treatment methods aimed at reducing those impacts.Recommendations for required future research addressing SP property and performance gaps are provided.

Evaluation of the clenbuterol imprinted monolithic column prepared by reversible addition-fragmentation chain transfer polymerization

To make more homogenous organic monolithic structure, reversible addition-fragmentation chain transfer （RAFT） process was employed in the synthesis of the clenbuterol imprinted polymer. In the synthesis, the influence of synthetic conditions on the polymer structure and separation efficiency was studied. The result demonstrated that the imprinted columns prepared with RAFT process have higher column efficiency and selectivity than the columns prepared with conventional polymerization in the present study, which may result from the higher surface area, smaller pore size and the narrower globule size distribution in their structures. The result indicated that RAFT polymerization provided better conditions for the clenbuterol imprinted monolithic polymer preparation. 2009 Xiang Chao Dong. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

ASSOCIATION OF ETHYLENE VINYL ACETATE COPOLYMER IN DILUTE SOLUTIONS IV. SOLVENT MIXTURE AND ADDITIVE EFFECT ON C_A

Critical association concentration (Ca) of ethylene-vinyl acetate copolymer (EVA) in selective solvent mixtures of 1,2-dichloroethane (DCE) (polar solvent) and cyclohexane (CYH) (non-polar solvent) was investigated. DCE is a good solvent for polyvinyl acetate (PVAc) and a poor solvent for paraffin, whereas CYH is a good solvent for the paraffin and a precipitant for PVAc. Viscosities of EVA in different compositions of the solvent mixture with and without additives were measured. Viscosity results were used to determine the C-A value of the systems. It is shown that C-A was markedly dependent on the composition of the solvent mixture and concentration and structure of the additive. Solvation and competition between hydrogen bonding and micellisation were suggested for qualitative description of the changing of C-A value observed.

Improved Transfer Process for the Fully Additive Manufacturing of a Conductive Layer-Stacked Polymeric Cantilever

This paper reports on an efficient fabrication process for a polymeric cantilever covered with conductive nano silver. The entire structure can be constructed additively using a printing process, without the use of an etching process or a sacrificial layer. The fabricated cantilever exhibits good linearity and forms a submillimeter-ordered air gap between itself and the substrate surface. Fine operation of a capacitive force gauge was obtained using the capacitance between the conductive cantilever and an electrode on the substrate. This process is expected to make possible the efficient manufacturing of various types of sensors that measure mechanical strain in a cantilever structure.

Application of New Polymeric Additive in Detergent for Automatic Dishwasher

This paper described a new type of multifunctional polymer Noverite^(TM) AD810's calcium ion chelating performance, tinted glass soaking test and its application in containing chlorine or enzyme automatic dishwashing detergent gel and powder. Results showed Noverite^(TM) AD810 has good performance in the final formulation on chelation, anti-filming, and anti-spotting, as well as to prevent the growth of scale crystals.

Review on the applications and developments of drag reducing polymer in turbulent pipe flow

Drag reduction phenomenon in pipelines has received lots of attention during the past decades due to its potential engineering applications, especially in fluid transporting industries. Various methods to enhance drag reduction have been developed throughout the years and divided into two categories;non-additives method and additives method. Both categories have different types of methods, with different formulations and applications which will generally be discussed in this review. Among all the methods discussed, drag reduction using polymer additive is as one of the most enticing and desirable methods. It has been the subject of research in this field and has been studied extensively for quite some time. It is due to its ability to reduce drag up to 80% when added in minute concentrations. Reducing drag in the pipe will require less pumping power thus offering economic relieves to the industries. So, this paper will be focusing more on the use of polymer additives as drag reducing agent, the general formulations of the additives, major issues involving the use of drag reducing polymers, and the potential applications of it. However, despite the extensive works of drag reduction polymer, there are still no models that accurately explain the mechanism of drag reduction. More studies needed to be done to have a better understanding of the phenomenon. Therefore, future research areas and potential approaches are proposed for future work.

Compound Rejuvenation of Polymer Modified Asphalt Binder

The objective of this research was to show a way to conduct rejuvenation of aged polymer modified asphalt binder（PMB） successfully.To fully evaluate and understand the rejuvenation of aged PMB,the Penetration grade tests including penetration,soften point,ductility and elastic recovery and SuperpaveTM PG grade tests including DSR,BBR and DDT were conducted.The rejuvenation effect of aged PMB by utilizing a fluid recycling agent in common use for binder rejuvenation was evaluated.And then the compound rejuvenation effect of aged PMB by utilizing the recycling agent with a new modifying additive for binder modification was evaluated.The experimental results indicated that the recycling agent in common use currently does not apply to polymer modified asphalt binder rejuvenation.But the recycling agent together with the modifying additive can restore the characteristics of aged polymer modified binder very well.Therefore,compound rejuvenation of polymer modified asphalt binder is recommended.

Advances in selective laser sintering of polymers

Polymers are widely used materials in aerospace,automotive,construction,medical devices and pharmaceuticals.Polymers are being promoted rapidly due to their ease of manufacturing and improved material properties.Research on polymer processing technology should be paid more attention to due to the increasing demand for polymer applications.Selective laser sintering(SLS)uses a laser to sinter powdered materials(typical polyamide),and it is one of the critical additive manufacturing(AM)techniques of polymer.It irradiates the laser beam on the defined areas by a computer-aided design three-dimensional(3D)model to bind the material together to create a designed 3D solid structure.SLS has many advantages,such as no support structures and excellent mechanical properties resembling injection moulded parts compared with other AM methods.However,the ability of SLS to process polymers is still affected by some defects,such as the porous structure and limited available types of SLS polymers.Therefore,this article reviews the current state-of-the-art SLS of polymers,including the fundamental principles in this technique,the SLS developments of typical polymers,and the essential process parameters in SLS.Furthermore,the applications of SLS are focused,and the conclusions and perspectives are discussed.

Polymerization of Norbornene via an Iron-Based Complex/MAO Catalytic System

Polynorbornenes were synthesized in the presence of an iron based catalyst, 2,6-bis[1-(2,6-diisopropyl-phenylimino)ethyl]pyridine iron(Ⅱ) dichloride. The FTIR, 1H NMR and 13C NMR analysis results revealed that the structure of the obtained polynorbornenes consisted of vinyl addition polymer substructures without any ring-opening structures. The polymers were amorphous with a short-range order, displayed in the WAXD(wide angle X-ray diffraction) diagrams. The glass transition temperatures ranged from 200 to 400 ℃. The effects of the polymerization reaction conditions, such as Al/Fe molar ratio and toluene/CH_2Cl_2 volume ratio, on the activity, intrinsic viscosity and T_g were also studied.

Stimulus-responsive mechanism of salt-responsive polymer and its application in saturated saltwater drilling fluid

AM-AMPS-TAC polymers with different charge distribution are synthesized using acrylamide(AM),2-acrylamido-2-methylpropanesulfonate(AMPS)and 3-acrylamidopropyl trimethylammonium(TAC)at different feed ratios by polymerization in solution.The salt-responsive behavior,reasons leading to salt-responsiveness,and effects of polymers molecular structure on salt-responsiveness are studied by laboratory experiments to find out the adaptability of the polymers.Rheology test under stepwise shear mode shows that the AM-AMPS-TAC polymers have salt responsiveness,and the closer the feeds of AMPS and ATC,the more significant the salt responsiveness will be.Conformation change of polymers molecular chain under salt stimulus is studied by turbidity test and micro-morphology analysis,and the responsive mechanism is further investigated by intrinsic viscosity test and copolymer composition analysis.Results indicate that the salt-responsive behavior of AM-AMPS-TAC polymers derives from the"curled to expanded"transition of chain conformation under salt stimulus,and this transition is led by the screening effect of salt which weakens polymers intramolecular ionic bond.Application in saturated saltwater drilling fluid shows that the AM90-AMPS5-TAC5 polymer has the best salt-tolerance and temperature-tolerance when used together with fluid loss controller PAC-Lv.The drilling fluid saturated with NaCl can maintain stable viscosity,good dispersion and low fluid loss for long time under 150℃.

Developments of Multifunctional Additives for High Quality Lube Oil

In most lubrication systems, the oil is mixed with air, in contact with air, in contact with metals and at high temperature. This is mean cause of premature lubricant, deterioration which can result in oxidation products, which are mainly acid. Hydrocarbon oxidation in the liquid phase proceeds by a radical chain reaction. In the present paper polyalkylphenol formaldehyde sulphonate and its ethoxylate were synthesized and evaluated as pour point depressant, viscosity improver and antioxidant. The efficiency of these additives depends on their chemical structure and degree of mixing (mole fraction). Values of surface tension of these additives were measured in oil phase and consequently CMC was determined for all additives and their mixtures. A novel method of inhibiting oxidation was proposed. The author suggests the mechanism of inhibiting oxidation according to surface activity of additive in oil phase. More confirmations for suggested mechanism were investigated by measuring the area occupied per molecule of additive at oil phase. The results indicate that the compatibility of sulphonate with ethoxylate group and forming stable micelle which acts as wax dispersant and improver viscosity.

Novel nanofiltration membranes with tunable permselectivity by polymer mediated phase separation in polyamide selective layer

Microstructure in selective layer has played a decisive role in permselectivity of nanofiltration(NF) membranes,and nanomaterials were well-known additives that had been applied to mediate the microstructure and permeability of polyamide NF membranes. However, nanoadditives generally displayed a poor dispersion in membranes or in fabrication process. To solve this problem, we showed an interesting concept that novel NF membranes with hybrid selective layer consisting of flexible polyisobutylene(PIB) and rigid polyamide could be fabricated from well-defined interfacial polymerization. The hydrophobic polymer mediated phase separation and microdomains formation in polyamide layer were found. The immiscibility between the rigid polyamide and flexible PIB as well as the resultant interface effect was interpreted as the reason for the polymer enhanced permselectivity, which was similar with the well-known thin film nanocomposite(TFN) membranes that nanoparticles incorporated contributed significantly to membrane permeability and rejection performance.Our results have demonstrated that novel NF membranes with enhanced performance can be prepared from immiscible polymers, which is a new area that has not been extensively studied before.

Synthesis of core-shell structured polymers with inserted thioether from a multi-functional scaffold

The synthesis of a thioether inserted, core-shell structured polymer from the scaffold of hyperbranched polyglycerol (PG) was described. PG was first allyl functionalized, and in the presence of AlBN, the allyl groups further underwent radical addition to thiol compounds, thus thiol functional polyethylene oxide monomether (MPEO) were grafted onto PG. Similarly, 2-mercaptoethylammonium chloride was introduced onto PG via thiol addition, and the residual amino groups were further quaternized with decyl bromide, leading to an amphiphilic core-shell structure polymer. (c) 2007 De Cheng Wan. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.