Emulsion Stability Test Research Articles

Pesticide Formulations as a Key Factor Affecting Chlorpyrifos-Ethyl and Lambda-Cyhalothrin Performance against Spodoptera littoralis (Boisd.)

Formulation is a term used in various senses in various applications, and its fundamental meaning is the putting together of components in an appropriate relationships or structures, according to a formula. Several prepared formulations for chlorpyrifos-ethyl and lambdacyhalothrin as Emulsifiable Concentrate (EC) formulation were subjected to WHO chemical tests to find out which formulation is matching the requirements. The physicochemical properties of the standard commercial formulation versus the prepared formulation were determined. The emulsion stability test was determined according to WHO specification method. Besides, the determination of free acidity and alkalinity as well as, viscosity and surface tension. The results of emulsion stability test indicated that the ml separation in the prepared formulation of chlorpyrifos was 0.1 ml cream after 1 hr in the case of hard water and 0.9 ml in soft water for chlorpyrifos 48% + Calcium dodecyl benzene sulfonate (CaDBS) 2.6% + Triton X-100 2.4% (F1) compared to < 0.1 ml and < 0.3 ml in hard and soft water respectively in the second formulation which consists of chlorpyrifos 48% + dodecyl benzene sulfonate (CaDBS) 2.8% + Triton X-100 2.2% (F2).The most successful prepared formulation was (F3) which consists of chlorpyrifos 48% + Calcium dodecyl benzene sulfonate (CaDBS) 3% + Triton X-100 2% with < 0.05 ml in both hard and soft water. While the ml separation in the commercial formulation of chlorpyrifos was 0.1 ml in hard water and 0.2 ml in soft water. The cream separation in emulsion stability test of prepared formulation of lambda-cyhalothrin was not observed after 1 hr in both hard and soft water for lambda-cyhalothrin 5% + dodecyl benzene sulfonate (CaDBS) 1.8% + Triton X-100 3.2% (F1) so it was the most successful prepared formulation compared to 0.9 ml in hard water and 0 ml in soft water in the second formulation which consists of lambda-cyhalothrin 5% + dodecyl benzene sulfonate (CaDBS) 2% + Triton X-100 3% (F2). While the ml separation in the commercial formulation of lambda-cyhalothrin was 0.4 ml cream + 0.3 ml oil in hard water and 0.7 ml cream + 0.2 ml oil in soft water. The most successful formulations were tested against susceptible and field strains of Spodoptera littoralis (Boisd.). The efficiency of the two prepared formulations were determined; in comparison with the standard (commercial) formulations of chlorpyrifos-ethyl and lambda-cyhalothrin respectively, against the susceptible and field strains of S. littoralis (Boisd.). Also, the effect of adding the synergist (Sylgard 309®) to each treatment was determined. In the susceptible strain after 48 hours bioassay; LC50 value for the prepared formulation of chlorpyrifos was10.12 ppm and after adding Sylgard 309® the result was found to be 7.14 ppm, while LC50 values for its commercial formulation alone and/or with Sylgard 309® were 13.74 and 9.61 ppm, respectively. LC50value for the prepared formulation of lambda-cyhalothrin was 85.70 ppm; after adding Sylgard 309® became 68.34 ppm, while LC50 for the commercial formulation of lambdacyhalothrin alone and/or with Sylgard 309® were 152.54 and 108.52 ppm, respectively. In the field strain after 48 hours bioassay; LC50 value for the prepared formulation of chlorpyrifos was 17.89 ppm, but with the addition of Sylgard 309®the result showed a magnificent effect as of 13.77 ppm. For its commercial formulation only and/or in addition to Sylgard 309® LC50 values were found to be 163.19 and 154.28 ppm respectively. LC50 value for the prepared formulation of lambda-cyhalothrin was 1212.62 ppm; with the addition of Sylgard 309® was slightly decreased to 1208.23 ppm, while LC50values for the commercial formulation only and/or in addition to Sylgard 309® were 1925.87 and 1914.77 ppm, respectively. The calculation of Resistance Factor (RF) after 48 hours bioassay revealed that the field strain compared to the susceptible one of S. littoralis showed a real case of resistance to both of the commercial formulations of chlorpyrifos and lambda-cyhalothrin while the prepared formulations of each showed either the natural tolerance or the vigor tolerance case, in respect.

A Simplified Methodology to Measure the Characteristic Curvature (Cc) of Alkyl Ethoxylate Nonionic Surfactants

AbstractThis work introduces a simplified methodology for measuring the characteristic curvature (Cc) of commercial alkyl ethoxylate nonionic surfactants using carefully selected reference surfactants and oils that produce rapid and well defined separations in salinity scans. The Cc of the commercial reference surfactants was calculated using optimal salinities (S*) obtained from solubilization parameter curves, from interfacial tensions (for a selected system), and from emulsion stability tests. The latter provided a fast detection of S*, in a matter of minutes. The calibrated Cc of the reference surfactants was subsequently used to measure the Cc of various commercial alkyl ethoxylate surfactants. The combination of mixtures of test and reference surfactants and emulsion stability tests produced reproducible Cc values that could be obtained with simple bottle tests and in a timely manner. The values obtained using this methodology were cross‐checked, and proved to be consistent, when using different combinations of reference surfactants and oils, and when conducted by different individuals. The standard deviation of Cc from these measurements was typically ±0.2 Cc units, but it could be as large as 25 % of the Cc value for highly hydrophilic surfactants. After comparing the values of Cc obtained experimentally with values calculated from nominal structures (via a group contribution model) it became clear that there are differences between these values, likely because of the polydispersity of alkyl ethoxylate surfactants.

Effect of the Water Content on Silica Gel for the Isolation of Interfacial Material from Athabasca Bitumen

The role of the water content adsorbed to silica gel for the selective isolation of petroleum interfacially active material was examined. Systematic variation of the amount of water adsorbed on the silica surface and its effect on retained petroleum species (interfacially active) revealed that gravimetric yields of isolated interfacial material (IM) were inversely proportional to the amount of water loaded onto the silica gel. However, with the exception of the water-saturated silica gel (66.6% water g–1 silica gel), all silica gels investigated (11.1–53.8% water g–1 silica gel) were stained after IM isolation, indicating that >53.8% water g–1 silica gel is required to prevent irreversible, oil–silica interactions. Moreover, emulsion stability tests reveal that IM isolated from the water-saturated silica gel (66.6% water g–1 silica gel) forms the most stable emulsion relative to IM isolated from the unsaturated silica gels. Molecular-level analysis of isolated IM fractions as a function of the silica wate...

Investigating the Impact of Crude Oil Solubility on Water-in-Oil Emulsion Stability and Its Relation to Molecular Composition of Crude Oil at the Oil–Water Interface

Substantial work in the literature has been devoted to studying emulsion stability caused by specific fractions of crude oil, such as asphaltenes or naphthenic acids. However, emulsion stability issues occur in the field with whole crude oil present and not just fractions. Understanding how all molecules in whole crude oils behave when the solubility parameter is varied could help to answer the question of what makes an emulsion stable from a molecular perspective. This work attempts to address solubility and the molecules that lead to emulsion stability from the whole crude oil perspective. Investigating the specific solubility class of molecules for emulsion stability limits understanding of interactions between different solubility classes, whether competitive or synergistic. In this work, emulsion stability and the composition of the interfacially active crude oil molecules are studied in parallel. Emulsion stability tests were performed with solutions containing different amounts of asphaltenes and having varied solubility parameter (by changing the heptane/toluene ratio). Heavy water extractions were also carried out to isolate crude oil molecules found at the water–crude oil interface. The separation of molecules is not related specifically to a solubility class or other chemical fractionation method. The separation is based on the molecular capability to form a stable emulsion and adhere to the water–oil interface. Crude oils separated from different heptol ratios exhibit both physical and chemical differences between one another, and compositions are compared to both whole crude oil and n-heptane asphaltenes.

Emulsifying properties of water soluble yellow mustard mucilage: A comparative study with gum Arabic and citrus pectin

The emulsifying properties of water soluble yellow mustard mucilage (WSM) were compared with two commercial emulsifiers—gum Arabic and citrus pectin. Of the three polysaccharides examined, WSM exhibited excellent emulsion stability under various conditions applied in this study. The emulsion stability test showed that 1% and 2% WSM emulsions exhibited no phase separation after 21 days of storage at 25 °C. WSM also exhibited the highest surface activity among the three materials. The surface activity of 1% WSM is equivalent to that of a 15% gum Arabic solution. When exposed to heat at 90 °C for 20 min, WSM emulsion showed little change in droplet size, which was superior to both the gum Arabic and pectin emulsions, whose droplet size increased significantly following heat treatment. WSM emulsion also had a significantly larger magnitude of zeta-potential than the other two polysaccharides. Under different pH conditions, droplet size varied greatly among the three materials. WSM emulsions exhibited significantly smaller droplet size at pH 4.0 followed by pH 9.0 and 6.5. Pectin emulsions and gum Arabic emulsions were not sensitive to the pH range examined in this study. WSM also showed the best freeze–thaw stability among the three polysaccharides. After three freeze–thaw cycles, the 0.5% WSM emulsion exhibited a higher cream index than 2% gum Arabic emulsion or the 1% pectin emulsion.

Optimization of the formulation of water in oil emulsions entrapping polysaccharide by increasing the amount of water and the stability

Water in oil emulsions entrapping a polysaccharide have been formulated and the purpose of this study is first to increase the amount of dispersed water and the amount of polysaccharide. The second part of the study is devoted to check the stability of the obtained emulsion over 2 years. Encapsulation of polysaccharide was realized by introducing the aqueous phase (containing the required polysaccharide and glycerol) into a stirred oil phase (wherein the polyglycerol polyricinoleate (PGPR) as the surfactant has been previously dissolved). Emulsion stability tests were carried out immediately after preparation and after ageing tests. For that purpose the emulsions were submitted to cooling and heating cycles performed in a calorimeter in order to detect the freezing and melting temperatures of the dispersed water. Due to nucleation phenomena, the delay between freezing and melting is correlated to the way the water is dispersed within the emulsion and therefore gives information about the stability of the emulsions. To complete these tests other ones were performed such as bottle test, laser diffraction granulometry and rheometry. It was shown that it is possible to get emulsions containing 75% of water, showing the required stability and flow ability.

Evaluation of Chemicals Interaction with Heavy Crude Oil through Water/Oil Emulsion and Interfacial Tension Study

A newly-designed surfactant was formulated to tolerate the harsh conditions of oil reservoirs, including high salinity of the formation brine and temperature. The specific emulsion and interfacial tension (IFT) behavior of this new surface active agent were investigated by performing emulsion stability tests, emulsion size analysis, and IFT behavior in the presence of four different types of alkalis. Image processing was utilized to analyze the droplet size distribution using microscopic images of the samples. The results show that depending on the composition of the mixtures, the optimum phase region and interfacial tension behavior change considerably. Solutions containing a higher percentage of the surfactant (around 1 wt %) show good emulsification capability at different salinities; however, adding any selected alkali to these mixtures reduces the optimum range of salinity tolerance. Mixtures of the surfactant and triethanolamine exhibit optimum three-phase region at higher salinity conditions compar...

Rheological behaviour of acrylate/montmorillonite nanocomposite latexes and their application in leather finishing as binders

The paper describes the rheological behaviour of nanocomposite latexes based on butylacrylate–co-methylmethacrylate–co-acrylamide terpolymers including various commercial nanoclays obtained via in situ emulsion polymerization. Rotational, oscillatory, emulsion stability and thixotropy tests (recovery) were performed to evaluate the influence of clay incorporation, type of clay and also emulsifier content in the composition of these nanomaterials. It was observed that the viscosities of the nanocomposite latexes were increased by clay incorporation at low shear rates, while a shear thinning effect was observed at higher shear rates. Oscillatory tests indicated a dominant elastic behaviour and high physical stabilities for all the nanocomposites. The hydrophobic character of the clay and emulsifier content also influenced the viscosity and dynamic modulus of the emulsions.The nanocomposite latexes were tested for leather finishing as polymeric binders. Results showed that the finish performance of the leather surfaces was improved by clay incorporation. It was also concluded that for coating applications it is important to find a balance between the compatibility of the nanoclay type with the polymer and the emulsifier amount necessary for emulsion stabilization which both influence the rheology and the final performance of the coatings.

Use of some emulsified plant seed oils as a safe alternative for the management of Meloidogyne incognita infecting tomato

The aim of the present study was to formulate six different plant seed oils namely canola, cotton, flax, olive, sesame and soybean as emulsifiable concentrates. The composition of the formulation comprises at least one organic solvent, one surfactant and one plant oil. Physico-chemical properties of the formulated oils (emulsion stability test, cold stability and heat stability tests) were measured. The successfully emulsified oils were evaluated for nematicidal activity against Meloidogyne incognita infecting tomato plants under greenhouse conditions. Emulsified canola oil proved to be the most effective oil as a protectant against M. incognita infection to tomatoes followed by soybean, cotton, flax and sesame oil. In addition, employing a high rate of the tested emulsified oils gave higher activity in suppressing nematodes both in the soil and in tomato roots than using a low rate. Moreover, all tested formulated oils at both rates of application had no adverse effect on the growth of tomato plants except sesame oil which significantly decreased the shoot length when compared to the control. The prepared plant oils might be used as potential sources for sustainable eco-friendly botanical nematicides to protect plants from nematode attack.

Monitoring and Predicting Emulsion Stability of Metalworking Fluids by Salt Titration and Laser Light Scattering Method

The prediction of emulsion stability is very important in the study, formulation, quality control, and technical service of metalworking fluids. Conventional emulsion stability test methods can be very time consuming. One quick method to determine emulsion stability is to titrate an emulsion with a salt solution until the emulsion separates. The salt (or electrolyte) concentration at which an emulsion starts to separate is called the critical coagulation concentration (CCC). The higher the CCC value, the more stable the emulsion. Another technique, called laser light scattering method, collects transmission and backscattering light by scanning emulsion samples with a laser. It is a very useful instrument to monitor emulsions and dispersions in kinetic studies of emulsion stability. The response of the laser light scattering method is very sensitive to any change in emulsion or dispersion stability. It has also been utilized in the quick selection of additives in semisynthetic metalworking fluids formulation. Presented at the STLE Annual Meeting in Las Vegas, Nevada, May 15–19, 2005 Review led by Jerry Byers

Biocides formulation of essential oils having antimicrobial activity

Essential oils of fennel, peppermint, caraway, eucalyptus, geranium and lemon were tested for their antimicrobial activities against some plant pathogenic micro-organisms (Fusarium oxysporum, Alternaria alternate, Penicilium italicum Penicilium digitatum and Botyritus cinerea). Essential oils of fennel, peppermint, caraway were selected as an active ingredient for the formulation of biocides due to their efficiency in controlling the tested micro-organisms. Successful emulsifiable concentrates (biocides) were prepared from these oils using different emulsifiers (Emulgator B.L.M. Tween20 and Tween80) and different fixed oils (sesame, olive, cotton and soybean oils). Physico-chemical properties of the formulated biocide (spontaneous emulsification, emulsion stability test, cold stability and heat stability tests as well as viscosity, surface tension and pH) were measured. The prepared biocides were ready to be tested for application in a future work as a safe pesticide against different pathogens.

Soybean lecithin fractionation and functionality

AbstractSoybean lecithin contains primarity PC, PE, and PI. Fractionation of these phospholipids (PL) is desirable for certain applications. Ethanol was used to fractionate PC and PI, which have different solubilities in this solvent. Various concentrations of ethanol (90, 95, and 100%) and ethanol/gum ratios (0.5, 1.0, 1.5, 2.0, and 2.5) were used. Ethanol concentration significantly influenced the yield of the PC‐enriched fraction and the PC and PI fractionation: The highest ethanol concentration resulted in the highest yield of PC fraction, the most PC in the PC fraction, and the most PI in the PI fraction. The ethanol/gum ratio significantly affected the yield of PC‐enriched fraction, but did not affect the relative PL composition of the PC‐enriched fraction. Ethanol of 90% concentration with a solvent/gum ratio of 3 was used for further large‐scale fractionation. Such fractionation resulted in a PC‐enriched fraction containing 73% PC, 24% PE, and 3% PI based on the total PL content, whereas the PI fraction contained 26% PC, 35% PE, and 39% PI. Functional properties of these two purified fractions, i.e., surface tension reduction, emulsion stability, and oxidative stability, were investigated. The PI‐enriched fraction had a much lower critical micelle concentration than the PC‐enriched fraction, which suggests the PI‐enriched fraction has a higher surface tension reduction capability. For the emulsion stability test, the PI‐enriched fraction performed better than the PC fraction in both water‐in‐oil and oil‐in‐water emulsions. An oxidative stability test showed that these PL were very stable to lipid oxidation.

Influence of water-soluble and water-insoluble natural surface active components on the stability of water-in-toluene-diluted bitumen emulsion

Bitumen, a very heavy crude oil, contains both water-soluble and water-insoluble natural surface active species. This study shows that complete removal of the water-soluble surface active species from bitumen by water extraction resulted in an increased emulsion stability and that the water-insoluble surface active asphaltenes are the key stabilizing agents for water-in-toluene-diluted bitumen emulsions. Separation of the toluene-diluted bitumen continuous phase from the emulsion by centrifuging at 1, 10, 100, 1000 and 10,000 g was conducted. Emulsion stability tests for the separated toluene-diluted bitumen and element analysis of the precipitated asphaltenes indicated that the asphaltenes in the separated organic continuous phase are different from those associated with the water droplet interface. The asphaltenes associated with the interface had a lower H/C ratio and a higher O/C ratio.

Synthesis and properties of polyurethane modified with an aminoethylaminopropyl-substituted polydimethylsiloxane. II. Waterborne polyurethanes

A series of polyurethane (PU) emulsions modified with aminosilicone were synthesized, based on 2,4-toluene diisocyanate (TDI), poly(tetramethylene oxide) (PTMO), and dimethylolpropionic acid (DMPA) as a prepolymer which was chain-extended with aminoethylaminopropyl polydimethylsiloxane (AEAPS) in an aqueous emulsion. Their chemical compositions, structures, bulk and surface properties, and emulsion morphologies were investigated using Fourier transform infrared spectrum analysis (FTIR), tensile and surface contact angle measurements, electron spectroscopy for chemical analysis (ESCA), water swellablity, an emulsion stability test, and transmission electron microscopy (TEM). It was shown that the PU emulsions were stable and the siloxane chains were enriched on the PU surface. The water resistance of the PU film increased but the bulk tensile properties of the PU film were not changed significantly with a small amount siloxane modification up to 6 wt %. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 295–301, 2001

Accelerated tests for predicting long-term creaming stability of infant formula emulsion systems

Models for sterilized, concentrated infant formulae were prepared from whey protein concentrate (WPC) and high-heat non-fat dry milk (NFDM) to yield a casein to whey ratio of 40:60%. The protein, carrageenan and lecithin levels were varied within a number of 2 × 3 factorial designs. Statistical techniques were used to evaluate the relationship of compositional factors to physical stability and to determine which emulsion stability test best predicted stability toward creaming after prolonged storage. Emulsion stability was assessed by gravitational and centrifugal creaming, relative viscosity, adsorbed protein and light scattering. Centrifugation and relative viscosity were the best predictors of 10 and 18-week stability, whereas emulsion activity index and particle size were poor predictors of stability in the infant formula model.

CHEMICAL AND PHYSICAL CHARACTERISTICS OF FRANKFURTERS PREPARED WITH MECHANICALLY PROCESSED PORK PRODUCT

ABSTRACTFrankfurters were prepared with frozen beef trim, pork fat, and 0, 10, 20, 30, 40, and 50% mechanically processed pork product (MPPP) produced by a hydraulic press deboner. Beef trim, salt, and ice were chopped to 8°C in a laboratory chopper, the appropriate amount of MPPP and pork fat added to maintain 25% fat, and the mixture was chopped to a final temperature of 135°C. Emulsion stability tests indicated that formulations with 30% or less MPPP were similar in smokehouse yield and percentage of water and fat lost during processing. Water‐holding capacity increased with increasing levels of MPPP, but frankfurters containing greater than 30% MPPP were softer in texture as determined by Warner‐Bratzler shear force values.

EFFECTS OF LEVELS OF FAT AND PROTEIN ON THE STABILITY AND VISCOSITY OF EMULSIONS PREPARED FROM MECHANICALLY DEBONED POULTRY MEAT

ABSTRACTA temperature controlled, capillary extrusion viscometer was used to compare meat batters prepared from mechanically deboned poultry meat (MDPM). Protein levels of 12% produced more viscous batters and less release of gel water and fat during emulsion stability tests than 11% protein. Product formulated with 21% fat gave less stable batters than meat with 16% fat; however, the viscosity of the meat batter increased with increased level of fat. Although meat batters prepared from two different sources of MDPM exhibited similar emulsion stability and extrusion capillary viscometry characteristics, a mixture of the meat from the two sources was lower in all components released during the emulsion stability test.