Synthesis of aminimides derived from oleic acid: a new family of drag-reducing surfactants

Large-scale syntheses of aminimide surfactants that serve as low temperature drag-reducing agents in ethylene glycol-water mixtures are described. Preliminary drag reduction results are presented and the susceptibility of the surfactants to methanolysis is discussed.     

Mass transfer between solid surfaces and drag-reducing fluids

The effect of drag-reducing agents on the rate of mass transfer from rotating cylinders was investigated. Significant reductions in the rate of mass transfer were obtained using aqueous solutions of Polyox WSR 301, Separan AP-30 and carboxymethylcellulose.A phenomenological interpretation of the data obtained, as well as of those reported for rotating disc and pipe flows, suggests that, in contrast with the case of drag reduction, large scale eddies play an important role in the process of mass transfer between solid surfaces and drag-reducing fluids.     

A Simple,Low-cost Method to Fabricate Drag-reducing Coatings on a Macroscopic Model Ship

A low-cost method was used to fabricate superhydrophobic coatings on a macroscopic model ship and the drag-reducing effect was investigated at both low and high speed. Hierarchical structures of the superhydrophobic copper coatings were characterized by means of scanning electron microscopy(SEM) and X-ray diffraction(XRD). Drag coefficient tests on surfaces with different wettability(superhydrophilic, hydrophilic, hydrophobic and superhydrophobic surfaces) showed that the as-prepared superhydrophobic surface exhibited a high remarkable drag reduction of 81% at a low speed of 1 mm/s. In the drag-reducing tests with model ship, the superhydrophobic coatings also exhibited around 16% drag reduction at a velocity of 0.3 m/s.     

A rheological model based on primary laboratory data of lubricants with polymers additives

The present work reports some experimental data consisting in traction behavior for lubricants with polymer additives. The rheological response of lubricants without polymer additives and with additives as a function of polymer concentration, pressure and temperature is discussed. Based on the laboratory data, the paper presents a quasi-empirical approach which predicts elastic shear modulus, limiting shear stress and characteristic shear stress of a lubricant with polymer additives.     

Effects of molar mass, concentration and thermodynamic conditions on polymer-induced flow drag reduction

Drag reduction in Taylor flow of polystyrene solutions is investigated using a commercial rheometer equipped with a standard double-gap sample holder with axial symmetry. The dependence of drag reduction on various factors, including polymer molar mass, polymer concentration, and thermodynamic conditions is studied. Drag reduction induced by polystyrene in toluene is found to increase with increasing polymer concentration in the dilute concentration regime. It is also seen that molecules with high molar mass of the polymer promote drag reduction. In terms of hydrodynamic volume fraction normalisation, it is found that most of the drag reduction effect occurs at volume fractions below 0.2. It is observed that drag reduction is favoured by good thermodynamic conditions of the polymer-solvent system. Both the flow induced extension of the polymer chains and the hydrodynamic volume fraction occupied by the polymer molecules seem to play an important role for the drag reduction effect.     

Fossil fuel applications of SFC and SFE: A review

The use of supercritical fluid technology for sample preparation and analysis in the petroleum industry will be described using various examples including: separation of petroleum fuels into hydrocarbon classes, determination of polynuclear aromatic hydrocarbon in soils and petroleum fuels, characterization of fuel-contaminated soil, assessment of fuel boiling point distribution, determination of polymer additives, and characterization of shale rock and drilling mud.     

Study the effect of antioxidants on biological activity and on homopolypropylene; mechanical and physical properties

Exposure of polymers to temperature, atmospheric oxygen, or even light could result in some degradation of the polymer properties and features during processing (application), storage and end use. In hydrocarbon polymers, the polymer tend to free radical formation, eventually resulting in chain damage or crosslinking that leads to degradation. Antioxidants are used to terminate these chain reactions by removing radicals. Antioxidants are used in most hydrocarbon polymers including, polypropylene. a good addiction package must be existed to overcome the effect of degradation and save the polymer shape and characteristics. The practical experiment was carried out on a pure polypropylene (intermediate polypropylene resin without additives) and another practical experiment but with adding several types of additives with a certain concentration and study the behavior of polypropylene in all cases with successive extrusions. On other hand Flexible molecular docking on heme oxygenase, an important stress protein that is involved in cellular protection, antioxidant and anti-inflammatory activities, justified the antioxidant activity of the isolated compounds. From the binding energy 3114 and 1680 they could consider to be powerful and available antioxidant.     

Structure and Stability of Polyvinyl Chloride

Abstract

Polyvinyl chloride (PVC) was first prepared in the laboratory over a hundred years ago. Due to its inherent instability the commercial applications of the polymer could only be developed after the development of effective means for its stabilization. PVC started to gain commercial significance in the late thirties and since then has continued to gain in importance. By using modifying agents (plasticizers, fillers, stabilizers, and other additives), it can be modified to exhibit an extremely wide range of properties.     

Direct sample injection in supercritical fluid chromatography with packed fused silica column

A direct sample injection technique was developed for supercritical fluid chromatography in a packed capillary column, with carbon dioxide as mobile phase and a flame ionization detector. The method allowed solutions, neat liquids, and even solids to be introduced as samples. Also, extraction with supercritical carbon dioxide was combined with this method to separate polymer additives.     

咪唑盐类聚离子液体抗菌剂的制备及其在水凝胶敷料中的应用

皮肤伤口的感染严重威胁患者的生命安全,虽然传统的含有银离子或小分子抗生素的抗菌水凝胶伤口敷料具有广谱的杀菌功效,但这些抗菌水凝胶敷料中的抗菌剂存在一定的生物毒性和耐药性风险,无法满足临床长期使用的要求.咪唑盐类聚离子液体由于其含有较强的正电荷效应以及疏水链段,因此其作为新型的聚合物抗菌剂具有较强的抗菌效果.本研究首先通...     

Wetting kinetics of films containing nonadsorbing polymers

Kinetics of wetting by a polymer solution have been studied theoretically for a film pinned to a slot. The fluid mechanical equations have been solved using a numerical scheme. The role of polymers appears in the disjoining pressure in the model. The spreading kinetics are observed to follow a power law: a power of 14 is observed at short times due to the Laplace pressure, and 12 at large times under the Hamaker part of the disjoining pressure at very large times and with no equilibration. It is argued and demonstrated that techniques which have low resolutions such as microscopy will measure quite different kinetics: at short times a power of 14 as for wetting liquids and then a sudden equilibration as reported in these experiments. It is also argued on the basis of steric exclusion, and quantified in the disjoining pressure, that the behavior returns to that of wetting liquids when the polymer molecular weight becomes very high, as also observed in the experiments. Examples of how these features can find practical applications, and hence, the importance of use of polymers as additives are given.     

Effects of Congo red on the drag reduction properties of poly(ethylene oxide) in aqueous solution based on drop impact images

The presence of very small amounts (ppm) of high-MW polymers in solution produces high levels of drag reduction in a turbulent flow. This phenomenon, often termed as the Toms effect, is highly dependent not only on MW, but also on the flexibility of the macromolecular chain. The Toms effect can be studied through the images of the structures produced after the drop impact against shallow solution surfaces. The splash structures composed of crown, cavity, and Rayleigh jet are highly dependent on the elongational properties of the solution. This work presents the effects of Congo red on the drag reduction properties of poly(ethylene oxide) in aqueous solutions through the analysis of splash structures. Results obtained in this analysis indicate that Congo red molecules act as physical cross-linking agents, decreasing the polymer elasticity and its drag reduction capacity. It was observed that the maximum height of the Rayleigh jet can be used as a sensitive parameter to the complexation between the dye and the polymer molecules.     

Influence of additives on the protoplasts electrofusion.

Various neutral or charged surface active substances were used for testing the influence of additives on the electrofusion of barley protoplasts. It was found that neutral surface active agents DX, TAGB, Span-80 and AEO-9 could promote the electrofusion. The positively charged surface active agents Bardac 2080, Bardac 2280 and amphoteric surface active agents dodecyl-propyl betaine and CAB betaine also promote the electrofusion, but at high concentration the electrofusion efficiency will reduce. The negatively charged polymer agents Cibacron blue DX, Fluoresceinylthiocarbamoyl DX, and active surface substances K12 and Carsonol TLS- presented negative effect. These phenomena were discussed from the view of adsorption of additives on the membrane and the interactions between protoplasts.     

Application of Waste Liquids Containing Lignin from Pulp-producing Industry to CWM Preparation

IntroductionSince the first oil crisis in1 973,coal conver-sion technologies such as coal gasification,lique-faction and combustion have been studied in orderto use coal as an alternative resource of oil.In thiscontext,coal water mixtures( CWMs) are attrac-tive because they are more transportable andstorable than non- treated coal for being used as analternative resource of oil.To prepare CWMs witha higher energy density,the coal concentrationshould be high in CWMs.However,high coal con-ce…     

Water-soluble ionic liquids as novel stabilizers in suspension polymerization reactions: engineering polymer beads

Aqueous solutions of ionic liquids have been used as novel and environmentally friendly reaction media to synthesize and "control" the size of different cross-linked polymer beads by suspension polymerization reactions. It was found that the investigated ionic liquids can act as novel stabilizing agents of the suspensions as a result of their surface-active properties. The results have demonstrated that the average size of polymer beads can be varied from the macro- to the nanoscale and their surface area can also be "adjusted" by this synthetic approach. Furthermore, the use of a combination of ionic liquids and water for the synthesis of polymers, the simple isolation of the products formed in this polymerization procedure, as well as the recycling of the continuous medium for further reactions open up possibilities for the development of "new and green" polymerization processes.     

Viscosities of liquids, colloidal suspensions, and polymeric systems under zero or non-zero electric field

The viscosities of pure liquids, polymer solutions and melts, and colloidal suspensions under zero or non-zero electric field are surveyed in this paper and the focus is placed on the case that no electric field is applied. The free volume concept and Eyring's rate theory is used for deriving the viscosity equations of pure liquids, polymer solutions and melts, and colloidal suspensions. The derived equations are found to be more universal and could be reduced to many currently used equations under certain simplifications. Qualitatively, those derived equations are in consistent with experimental results, too.     

The use of cationic surfactants and ionic liquids in the detection of microbial contamination by capillary electrophoresis

A rapid test of whether a laboratory sample contains any microorganisms is important and necessary for many areas of science and technology. Currently, most of the standard procedures for the detection of aerobic bacteria, anaerobic bacteria and fungi, require the preparation of microbial cultures in respective growth media, which are dramatically slow. Different approaches providing fast analysis such as CE are becoming more desired. To compensate for the natural electrophoretic heterogeneity of microbes, various buffer additives were examined to stack all bacteria and fungi in a sample plug into a single peak. This peak was removed from the molecular contaminants in the sample to prevent false positives. Both cationic surfactants and ionic liquids (IL) were investigated as run buffer additives and they are both widely applicable to different species of bacteria and fungi. Given that high concentrations of surfactants can potentially lyse cells, dicationic IL offer attractive auxiliary buffer additives for use in CE-based sterility tests. The analysis can be completed in 10 min, thus providing a great advantage over traditional direct inoculation methods that require several weeks to complete.     

Photodegradation of poly(methyl methacrylate) studied by ESR and viscosity measurements

The photodegradation of poly(methyl methacrylate) has been investigated by electron spin resonance and viscosity measurements. On UV irradiation of poly(methyl methacrylate) film at 40°C in either a vacuum or in air, radicals were produced. Although the observed radical concentration in air is considerably different from that in a vacuum, the number of radicals responsible for the chain scission processes were almost the same in both cases. When the polymer film is irradiated with light of wavelength longer than 290 nm, radical formation is suppressed and the viscosity average molecular weight remains unchanged. The photodegradation has also been examined for poly(methyl methacrylate) films containing benzophenone and 2-hydroxy-4-methoxybenzophenone. Both additives were found to act as protective agents for the polymer. A mechanism of protection by these additives against photodegradation is proposed on the basis of the experimental results.     

Utilization of α-olefins obtained by pyrolysis of waste high density polyethylene to synthesize α-olefin-succinic-anhydride based cold flow improvers

A new route of utilization of α-olefin rich hydrocarbon fractions obtained by waste polymer pyrolysis was investigated. α-olefin-succinic-anhydride intermediate-based pour point depressant additives for diesel fuel were synthesized, in which reactions needed α-olefins were obtained by pyrolysis of waste high-density polyethylene (HDPE). Fraction of α-olefins was produced by the de-polymerization of plastic waste in a tube reactor at 500℃ in the absence of catalysts and air. C17～22 range of mixtures of olefins and paraffins were separated for synthesis and then, these hydrocarbons were reacted with maleic-anhydride (MA) for formation of α-olefin-succinic-anhydride intermediates. The olefin-rich hydrocarbon fraction contained approximately 60% of olefins, including 90%～95% α-olefins. Other intermediates were produced in the same way by using commercial C20 α-olefin instead of C17～22 olefin mixture. The two different experimental intermediates with number average molecular weights of 1850g/mol and 1760g/mol were reacted with different alcohols: 1-butanol, 1-hexanol, 1-octanol, i-butanol, and c-hexanol to produce their ester derivatives. The synthesized ten experimental pour point depressants were added in different concentrations to conventional diesel fuel, which had no other additive content before. The structure and efficiency of experimental additives were followed by different standardized and non-standardized methods. Results showed that the experimental additives on the basis of the product of waste pyrolysis were able to decrease not only the pour but also the cloud point and cold filter plugging point (CFPP) of diesel fuel, whose effects could be observed even if the concentration of additives was low. Furthermore, all additives had anti-wear and anti-friction effects in diesel fuel.     

Tailoring of interfacial properties by ionic liquids in a fluorinated matrix based nanocomposites

Different ionic liquids based on alkyltriphenylphosphonium and imidazolium-functionalized either with two alkyl chains or with a fluorinated chain have been synthesized and used as interfacial agents for the layered silicates. The effect of the chemical nature of the organic cation on the morphology and the physical properties of the polyvinylidene fluoride (PVDF) nanocomposites has been studied. The influence of ionic liquids on polymorphic crystalline forms, i.e. α and β phases of the polymer matrix was discussed.