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1.
In order to improve the water solubility of sugar‐based surfactants, alkyl β‐d‐ xylopyranosides, novel sugar‐based surfactants, 1,2‐trans alkoxyethyl β‐d‐ xylopyranosides, with alkyl chain length n = 6–12 were stereoselectively prepared by the trichloroacetimidate method. Their properties including hydrophilic–lipophilic balance (HLB) number, water solubility, surface tension, emulsification, foamability, thermotropic liquid crystal, and hygroscopicity were investigated. The results indicated that their HLB number decreased with increase of alkyl chain, the water solubility improved since the hydrophilic oxyethene (─OCH2CH2─) fragment was introduced. The dissolution process was entropy driven at 25–45 °C for alkyl chain length n = 6–10. Octyloxyethyl β‐d‐ xylopyranoside had the best foaming ability. Nonyloxyethyl β‐d‐ xylopyranoside had the best foam stability and the emulsifying ability was better in toluene/water system than in rapeseed oil/water system. The surface tension of in aqueous solution dropped to 27.8 mN m?1 at the critical micelle concentration, and it also showed the most distinct thermotropic liquid phases with cross pattern texture upon heating and the fan schlieren texture on cooling. Hexyloxyethyl β‐d‐ xylopyranoside possessed the strongest hygroscopicity. Based on the effective improvement of water solubility, the prepared alkoxyethyl β‐d‐ xylopyranosides showed excellent surface activity and are expected to develop their practical application as a class of novel sugar‐based surfactants.  相似文献   

2.
In this study, the extraction of jojoba seed oil obtained from jojoba seed using both supercritical CO2 and supercritical CO2+ethanol mixtures was investigated. The recovery of jojoba seed oil was performed in a green and high-tech separation process. The extraction operating was carried out at operating pressures of 25, 35 and 45 MPa, operating temperatures of 343 and 363 K, supercritical fluid flow rates of 3.33 × 10−8, 6.67 × 10−8 and 13.33 × 10−8 m3 s−1, entrainer concentrations of 2, 4 and 8 vol.%, and average particle diameters of 4.1 × 10−4, 6.1 × 10−4, 8.6 × 10−4 and 1.2 × 10−3 m. It was found that a green chemical modifier such as ethanol could enhance the solubilities, initial extraction rate and extraction yield of jojoba seed oil from the seed matrix as compared to supercritical CO2. In addition, it was found that the solubility, the initial extraction rate and the extraction yield depended on operating pressure and operating temperature, entrainer concentration, average particle size and supercritical solvent flow rate. The solubility of jojoba seed oil and initial extraction rate increased with temperature at the operating pressures of 35 and 45 MPa and decreased with increasing temperature at the operating pressure of 25 MPa. Furthermore, supercritical fluid extraction involved short extraction time and minimal usage of small amounts entrainer to the CO2. About 80% of the total jojoba seed oil was extracted during the constant rate period at the pressure of 35 and 45 MPa.  相似文献   

3.
Enzymes can decrease the environmental and economic load of detergent products by reducing the amount of chemicals used in detergents and by allowing washing at ambient temperatures. In this study, Streptomyces cellulosae AU‐10 (GenBank accession number: MG780240) lipase was purified 7.08‐fold with 68% yield using an aqueous 2‐phase system. The Streptomyces sp. AU‐10 lipase showed maximal activity at pH 9.0 and 40 °C. Hundred percent activities were measured in the pH range from 9.0 to 11.0 for 1 h. The enzyme was also highly stable at 30–50 °C. The values of Km and Vmax were calculated as 0.34 mM and 0.83 mM min?1, respectively. The lipase has high hydrolytic activity for olive oil and sunflower oil. The effect of ethylenediamine tetraacetic acid on the enzyme has shown that the lipase is a metalloenzyme. The activity increased in the presence of Fe2+, Cu2+, and various boron compounds. The enzyme has shown a good stability not only with surfactants but also with oxidizing agents. In addition, activities in the presence of Omo, Ariel, Tursil, Pril, and Fairy were measured as 108.8%, 115.6%, 98.35%, 140.4%, and 107.6%, respectively. Considering its remarkable ability, the S. cellulosae AU‐10 lipase can be considered as a potential additive in the detergent industry.  相似文献   

4.
In this work, a novel series of zwitterionic gemini surfactants with different hydrophobic tails were synthesized and characterized. The physico‐chemical properties of these products (such as surface tension, oil/water interfacial tension, foaming ability, and the wetting ability of paraffin‐coated sandstone) were fully studied. The CMC of the synthesized surfactants ranged from 2.17 × 10?4 mol L?1 to 5.36 × 10?4 mol L?1 and corresponding surface tension (γCMC) ranged from 26.49 mN m?1 to 29.06 mN m?1, which showed excellent efficiency among the comparison surfactants. All the products can reduce the interfacial tension to a relatively low level of about 0.1–1.0 mN m?1. Additionally, results from applying different hydrocarbons suggested that the synergy will be clearer and oil/water interfacial tension will be lower if the oil components are similar to the surfactants. Contact angle and foaming measurements indicated that the surfactants exhibited good wetting and foaming abilities. The results of oil flooding experiments using an authentic sandstone microscopic model showed that C‐12 and CA‐12 could effectively improve the displacement efficiency by 21–29 %.  相似文献   

5.
Esters of castor oil and hydrogenated castor oil were prepared with C6, C12, C16, C18 fatty acids, using tetra‐n‐butyl titanate as a catalyst and n‐butyl benzene as a water entrainer. Physical properties such as melting point, refractive index, viscosity, and specific gravity of these esters were measured. Slip melting points of the esters were very low in both cases. These esters did not crystallize even at low temperature. The highest slip melting point obtained was 21 °C with stearoyl hydrogenated castor oil ester and lowest slip melting point obtained was —6 °C with hexanoyl castor oil ester.  相似文献   

6.
Sn‐doped CdS/TiO2 heterojunction was synthesized on the conducting polymer fiber mat by hydrothermal method. The conducting polymer fiber mat was made by electrospinning from polyvinylidene fluoride, styrene‐maleic anhydride copolymer, and nano‐graphites as conducting fillers. The Sn‐doped CdS/TiO2 heterojunction was characterized by XRD, XPS, SEM, TEM, TGA, and UV–Vis absorption spectra. Under simulated solar light irradiation, a combination of Sn‐doped CdS/TiO2/conducting polymer was found to be highly efficient for photocatalytic hydrogen evolution from splitting of water. The photocatalytic hydrogen production efficiency was up to 2885 μmol h?1 g?1cat. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42300.  相似文献   

7.
Hyperbranched polyurethanes were synthesized from poly(ε‐caprolactone) diol as a macroglycol, butanediol as a chain extender, a monoglyceride of a vegetable oil (Mesua ferrea, castor, and sunflower oils separately) as a biobased chain extender, triethanolamine as a multifunctional moiety, and toluene diisocyanate by a prepolymerization technique with the A2 + B3 approach. The structure of the synthesized hyperbranched polyurethanes was characterized by 1H‐NMR and X‐ray diffraction studies. M. ferrea L. seed‐oil‐based polyurethane showed the highest thermal stability, whereas the castor‐oil‐based one showed the lowest. However, the castor‐oil‐based polyurethane exhibited the highest tensile strength compared to the other vegetable‐oil‐based polyurethanes. All of the vegetable‐oil‐based polyurethanes showed good shape fixity, although the castor‐oil‐based polyurethane showed the highest shape recovery. Thus, the characteristics of the vegetable oil had a prominent role in the control of the ultimate properties, including the shape‐memory behaviors, of the hyperbranched polyurethanes. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39579.  相似文献   

8.
In this research, a star‐shaped surfactant was synthesized through the chlorination reaction, alkylation reaction and sulfonation reaction of triethanolamine, which is composed of three hydrophobic chains and three sulfonate hydrophilic groups. The critical micelle concentration (CMC) of the surfactant was measured by the surface tension method, and the results showed that it had high surface activity with CMC of 5.53 × 10?5 mol/L. The surfactant was superior in surface active properties to the reference surfactants SDBS and DADS‐C12. The interfacial tension (IFT) of the studied crude oil–water system (surfactant concentration 0.1 g/L, NaOH concentration 0.5 g/L, and experimental temperature 50 °C) dropped to 1.1 × 10?4 mN/m, which can fulfil the requirement of surfactants for oil displacement. An aqueous solution of the surfactant and crude oil was emulsified by shaking, which formed a highly stable oil‐in‐water (O/W) emulsion with particle size of 5–20 μm. The oil displacement effect was almost 12%.  相似文献   

9.
The esterification of castor oil with lauric acid was investigated using tetra n-butyl titanate (TBT), SnCl2·2H2O (stannous chloride), CoCl2·6H2O (cobalt chloride), and (CH3COO)2Zn·2H2O (zinc acetate dihydrate) as catalysts. Effects of catalyst concentration and reaction temperature on the progress of the reaction were investigated. TBT was the best catalyst for the esterification of castor oil with lauric acid at temperatures lower than 200°C. The reaction was first order with respect to each reactant. The activation energy for the esterification reaction of castor oil with lauric acid using TBT was 26.69 kcal/mol. The rate constants obtained for the esterification of castor oil with decanoic, lauric, palmitic, and stearic acids were nearly the same (15.80, 15.44, 15.06, and 14.67 mL mol−1 min−1), as were the rate constants obtained for the reaction of castor oil and hydrogenated castor oil.  相似文献   

10.
Micrometer‐ and nanometer‐Al2O3‐particle‐filled poly(phthalazine ether sulfone ketone) (PPESK) composites with filler volume fractions ranging from 1 to 12.5 vol % were prepared by hot compression molding. We evaluated the tribological behaviors of the PPESK composites with the block‐on‐ring test rig by sliding PPESK‐based composite blocks against a mild carbon steel ring under dry‐friction conditions. The effects of different temperatures on the wear rate of the PPESK composites were also investigated with a ball‐on‐disc test rig. The wear debris and the worn surfaces of the PPESK composites were investigated with scanning electron microscopy, and the structures of the PPESK composites were analyzed with IR spectra. The lowest wear rate, 7.31 × 10?6 mm3 N?1 m?1, was obtained for the composite filled with 1 vol %‐nanometer Al2O3 particles. The composite with nanometer particles exhibited a higher friction coefficient (0.58–0.64) than unfilled PPESK (0.55). The wear rate of 1 vol %‐nanometer‐Al2O3‐particle‐filled PPESK was stable and was lower than that of unfilled PPESK from the ambient temperature to 270°C. We anticipate that 1 vol %‐nanometer‐Al2O3‐particle‐filled PPESK can be used as a good frictional material. We also found that micrometer‐Al2O3‐particle‐filled PPESK had a lower friction coefficient at a filler volume fraction below 5%. The filling of micrometer Al2O3 particles greatly increased the wear resistance of PPESK under filler volume fractions from 1 to 12.5%. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 993–1001, 2005  相似文献   

11.
Injected chemical flooding systems with high salinity tolerance and fast‐dissolving performance are specially required for enhancing oil recovery in offshore oilfields. In this work, a new type of viscoelastic‐surfactant (VES) solution, which meets these criteria, was prepared by simply mixing the zwitterionic surfactant N‐hexadecyl‐N,N‐dimethyl‐3‐ammonio‐1‐propane sulfonate (HDPS) or N‐octyldecyl‐N,N‐dimethyl‐3‐ammonio‐1‐propane sulfonate (ODPS) with anionic surfactants such as sodium dodecyl sulfate (SDS). Various properties of the surfactant system, including viscoelasticity, dissolution properties, reduction of oil/water interfacial tension (IFT), and oil‐displacement efficiency of the mixed surfactant system, have been studied systematically. A rheology study proves that at high salinity, 0.73 wt.% HDPS/SDS‐ and 0.39 wt.% ODPS/SDS‐mixed surfactant systems formed worm‐like micelles with viscosity reaching 42.3 and 23.8 mPa s at a shear rate of 6 s?1, respectively. Additionally, the HDPS/SDS and ODPS/SDS surfactant mixtures also exhibit a fast‐dissolving property (dissolution time <25 min) in brine. More importantly, those surfactant mixtures can significantly reduce the IFT of oil–water interfaces. As an example, the minimum of dynamic‐IFT (IFTmin) could reach 1.17 × 10?2 mN m?1 between the Bohai Oilfield crude oil and 0.39 wt.% ODPS/SDS solution. Another interesting finding is that polyelectrolytes such as sodium of polyepoxysuccinic acid can be used as a regulator for adjusting IFTmin to an ultralow level (<10?2 mN m?1). Taking advantage of the mobility control and reducing the oil/water IFT of those surfactant mixtures, the VES flooding demonstrates excellent oil‐displacement efficiency, which is close to that of polymer/surfactant flooding or polymer/surfactant/alkali flooding. Our work provides a new type of VES flooding system with excellent performances for chemical flooding in offshore oilfields.  相似文献   

12.
Maleic anhydride modified soybean‐ and castor‐oil‐based monomers, prepared via the malination of the alcoholysis products of the oils with various polyols, such as pentaerythritol, glycerol, and bisphenol A propoxylate, were copolymerized with styrene to give hard rigid plastics. These triglyceride‐based polymers exhibited a wide range of properties depending on their chemical structure. They exhibited flexural moduli in the 0.8–2.5 GPa range, flexural strength in the 32–112 MPa range, glass transition temperatures (Tg) ranging from 72 to 152°C, and surface hardness values in the 77–90 D range. The polymers prepared from castor oil exhibited significantly improved modulus, strength, and Tg values when compared with soybean‐oil‐based polymers. These novel castor and soybean‐oil‐based polymers show comparable properties to those of the high‐performance unsaturated polyester (UP) resins and show promise as an alternative to replace these petroleum‐based materials. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1497–1504, 2006  相似文献   

13.
In this work, acrylic/acrylate copolymeric surfactants, which can be used in the preparation of pesticide oil‐in‐water emulsions (EW), were synthesized by emulsion polymerization, using potassium persulfate (K2S2O8) as an initiator, dodecyl mercaptan (DDM) as a chain transfer agent at the temperature range of 82–85°C. When the weight ratio of monomers was m(butyl acrylate) : m(methyl methacrylate) : m(acrylic acid) = 4 : 4 : 1.6 and the dosage of DDM was 2% (percentage of monomer mass), the prepared acrylic/acrylate copolymeric surfactants had a number‐average molecular weight of 2.5 × 104 and exhibited good stability for pesticide EW. The carboxylic group distribution studies show that only the surface carboxylic groups make dispersed pesticide oil droplets more stable. The acrylic/acrylate copolymeric surfactants prepared by shot‐monomer had the most surface carboxylic group distribution (46.6%). To obtain greater surface carboxylic group distribution, maleic anhydride (MA) was used to modify the polymer system. Adding 2% MA (percentage of monomer mass) to the polymerization system, the surface carboxylic groups were increased 12% over unmodified acrylic/acrylate copolymeric surfactants. Compared with traditional pesticide EW, the avermectin EW prepared with acrylic/acrylate polymeric surfactant had much better stability. Meanwhile, its pesticide effect was similar to that of a control (1.8% abamectin emulsifiable solution). © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012  相似文献   

14.
In order to enhance oil recovery from high‐salinity reservoirs, a series of cationic gemini surfactants with different hydrophobic tails were synthesized. The surfactants were characterized by elemental analysis, infrared spectroscopy, mass spectrometry, and 1H‐NMR. According to the requirements of surfactants used in enhanced oil recovery technology, physicochemical properties including surface tension, critical micelle concentration (CMC), contact angle, oil/water interfacial tension, and compatibility with formation water were fully studied. All cationic gemini surfactants have significant impact on the wettability of the oil‐wet surface, and the contact angle decreased remarkably from 98° to 33° after adding the gemini surfactant BA‐14. Under the condition of solution salinity of 65,430 mg/L, the cationic gemini surfactant BA‐14 reduces the interfacial tension to 10?3 mN/m. Other related tests, including salt tolerance, adsorption, and flooding experiments, have been done. The concentration of 0.1% BA‐14 remains transparent with 120 g/L salinity at 50 °C. The adsorption capacity of BA‐14 is 6.3–11.5 mg/g. The gemini surfactant BA‐14 can improve the oil displacement efficiency by 11.09%. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46086.  相似文献   

15.
In spite of the increasing interest in cold temperature detergency of vegetable oils and fats, very limited research has been published on this topic. Extended surfactants have recently been shown to produce very promising detergency with vegetable oils at ambient temperature. However, the excessive salinity requirement (4–14 %) for these surfactants has limited their use in practical applications. In this work, we investigated the mixture of a linear C10–18PO–2EO–NaSO4 extended surfactant and a hydrophobic twin‐tailed sodium dioctyl sulfosuccinate surfactant for cold temperature detergency of vegetable oils and semi‐solid fats. Four vegetable oils of varying melting points (from ?10 to 28 °C) were studied, these were canola, jojoba, coconut and palm kernel oils. Anionic surfactant mixtures showed synergism in detergency performance compared to single surfactant systems. At temperatures above the melting point, greater than 90 % detergency was achieved at 0.5 % NaCl. While detergency performance decreased at temperatures below the melting point, it was still superior to that of a commercial detergent (up to 80 vs. 40 %). Further, results show that the experimental microemulsion phase behaviors correlated very well with predictions from the hydrophilic–lipophilic deviation concept.  相似文献   

16.
Two semiinterpenetrating polymer networks (semi‐IPNs) based on trihydroxyl methylpropane–polyurethane (T‐PU) or castor oil–polyurethane (C‐PU) were prepared by curing the mixed solution of the polyurethane prepolymer and nitrochitosan (NCH). During the curing process, crosslinking and grafting reaction between the molecules of the PU prepolymer and NCH occurred, because of the high reactivity of remaining hydroxyl groups in the NCH with ? NCO groups of PU. The structure of the original semi‐IPN sheets and the sheets treated with acetone were studied by infrared, 13C‐NMR, scanning electron microscopy, and dynamic mechanical analysis, showing interpenetration of NCH molecules into the PU networks. When nitrochitosan content (CNCH) was lower than 10 wt %, the semi‐IPN sheets T‐PU and C‐PU had higher density and tensile strength (σb) than the systems with CNCH more than 20%. The trihydroxymethyl propane‐based PU reacted more readily with nitrochitosan to form the semi‐IPNs than castor oil‐based PU. The semi‐IPN coatings T‐PU and C‐PU were used to coat cellophane, resulting in intimate interfacial bonding. The mechanical strength and water resistivity of the cellophane coated with T‐PU coating were improved remarkably. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3109–3117, 2001  相似文献   

17.
Photocatalytic water splitting for hydrogen production was recognized as an effective strategy to obtain renewable energy for solving the environmental pollution and resource shortage crisis. Herein, we explored the solvothermal deposition method to successfully prepare blanket-like Bi2MoO6 coated on TiO2 nanotube arrays (TiO2 NTA/Bi2MoO6), and the TiO2 NTA/Bi2MoO6 photocatalyst showed outstanding visible light-driven photocatalytic water splitting capacity, and the hydrogen evolution rate achieved 129.26 μmol h-1 cm-2. Moreover, the sample also exhibited high photocatalytic pollutant decomposition performance. The remarkable photocatalytic performance was attributed to the synergistic effect of Bi2MoO6 and TiO2 NTA in the matched energy band location for solar absorption and carrier transportation. The synthesis and photocatalytic water splitting of Bi2MoO6/TiO2 NTA could afford the reproducible lesson for novel resource utilization of semiconductor photocatalysts.  相似文献   

18.
The properties of jojoba oil make it uniquely suited as a raw material for the cosmetics industry. Water-based, thermodynamically stable preparations of jojoba oil are essential in many formulations. New microemulsions were prepared based on jojoba oil and different nonionic surfactants, namely polyoxyethylene-(ethylene oxide)10-oleyl alcohol (Brij 96V) and ethoxylated sorbitan esters (Tweens). The effects of the surfactants and of primary alcohols as cosurfactants on the isotropic regions of the phase diagram were elucidated. It was found that, up to a certain cosurfactant chain length, the isotropic region expanded considerably as chain length increased. The size of the isotropic region also increased as a function of the ethylene glycol content of the aqueous phase in microemulsions based on ethoxylated alcohol but shrank when ethylene glycol was included in microemulsions prepared with ethoxylated sorbitan esters. Secondary structural phase transitions from water-in-oil to bicontinous and to oil-in-water structures (as determined by measuring conductivity and viscosity) were found to be related to jojoba oil content. Dynamic light scattering and small angle X-ray scattering studies established that incorporation of jojoba oil into Brij 96V micelles caused micellar transformation from elongated to spherical droplets and a decrease in the aggregation number.  相似文献   

19.
In this study, 2 types of amino acid‐based biosurfactants such as potassium cocoyl glycinate (CGK) and sodium cocoyl glycinate (CGN) were synthesized from coconut oil. Their chemical structures were identified using FT‐IR, 1H NMR, and 13C NMR spectroscopies. Characterization of their interfacial properties has shown that both CGK and CGN surfactants are surface‐active and effective in reducing interfacial free energy. Washing test results indicated relatively good detergency compared with surfactants commonly employed in detergent applications. From environmental compatibility tests, both CGK and CGN are found to be readily biodegradable, nontoxic, nonirritating, and very mild. In particular, the CGK surfactant was found to be more efficient in reducing interfacial free energy since a larger number of CGK molecules are preferentially adsorbed at the air–water interface due to higher hydrophobicity and larger mobility of CGK than CGN, indicating possible uses in detergent applications.  相似文献   

20.
Porous ultrahigh‐molecular‐weight polyethylene (UHMWPE)‐based composites filled with surface‐modified Ce‐doped TiO2 nanoparticles (Ce–TiO2/UHMWPE) were prepared by template dissolution. The composites were characterized by Fourier transform infrared spectroscopy, ultraviolet (UV)–visible spectroscopy, diffuse reflectance spectra, and scanning electron microscopy); the photocatalytic activity was also evaluated by the decomposition of methyl orange under UV exposure. The results demonstrate that the severe aggregation of Ce–TiO2 nanoparticles could be reduced by surface modification via a silane coupling agent (KH570). The Ce–TiO2/UHMWPE porous composites exhibited a uniform pore size. Doping with Ce4+ effectively extended the spectral response from the UV to the visible region and enhanced the surface hydroxyl groups of the TiO2 attached to the matrix. With a degradation rate of 85.3%, the 1.5 vol % Ce–TiO2/UHMWPE sample showed the best photocatalytic activity. The excellent permeability of the porous composites is encouraging for their possible use in wastewater treatment. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013  相似文献   

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