Hydrophilic-lipophilic Balance Values Research Articles

MPEG grafted quaternized carboxymethyl chitosan for demulsification of crude oil emulsions

ABSTRACTFour novel environmentally friendly and highly branched crude oil demulsifiers were prepared by using different molecular weight (Mn = 350, 750, 1000, 1900 g/mol) of methoxy poly(ethylene glycol) to modify quaternized N,O‐carboxymethyl chitosan. Fourier transform infrared and 1H‐nuclear magnetic resonance were employed to confirm the structure of the demulsifiers. The surface tension of demulsifies was determined and hydrophile–lipophile balance value was calculated at the critical micelle concentration. The demulsification performance was evaluated by the bottle test method against water‐in‐oil emulsions simulated in the laboratory and it was found that the dehydration rate of four demulsifiers can come to 74.2%–80.4%, which have better demulsification performance than the commercial demulsifier JL‐1. Demulsification mechanism was discussed, and it was encouraging to find that the tiny water droplets in the emulsion coalesced to form the water phase and separated with the water from the polarization microscope. Results show that methoxy poly(ethylene glycol) grafted quaternized carboxymethyl chitosan has a promising application as a demulsifiers for dealing with W/O crude oil emulsions. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45867.

Understanding the Capsanthin Tails in Regulating the Hydrophilic-Lipophilic Balance of Carbon Dots for a Rapid Crossing Cell Membrane.

Here we use natural Chinese paprika to prepare a new kind of amphiphilic carbon dot (A-Dot) that exhibits bright, multicolored fluorescence and contains hydrophilic groups as well as lipophilic capsanthin tails on the surface. It is found that the capsanthin tails in a phospholipid-like structure can promote cell internalization of the A-Dots via crossing cell membranes rapidly in an energy-independent fashion. Compared to highly hydrophilic carbon dots (H-Dots), a control sample prepared from the microwave thermolysis of citric acid and ethylenediamine, our synthesized A-Dots can be taken up by CHO, HeLa, and HFF cells more easily. More importantly, we develop a method to calibrate the hydrophilic-lipophilic balance (HLB) values of various kinds of carbon dots (C-Dots). HLB values of A-Dots and H-Dots are determined to be 6.4 and 18.4, respectively. Moreover, we discover that the cellular uptake efficiency of C-Dots is closely related to their HLBs, and the C-Dots with an HLB value of around 6.4 cross the cell membrane easier and faster. As we regulate the HLB value of the A-Dots from 6.4 to 15.3 by removing the capsanthin tails from their surfaces via alkali refluxing, it is found that the refluxed A-Dots can hardly cross HeLa cell membranes. Our work is an essential step toward understanding the importance of regulating the HLB values as well as the surface polarity of the C-Dots for their practical use in bioimaging and also provides a simple but effective way to judge whether the C-Dots in hand are appropriate for cell imaging.

Surfactant concentration and type affects the removal of Escherichia coli from pig skin during a simulated hand wash.

This study characterizes the role of surfactants in removing microbes during a hand wash. Numerous studies address how surfactants support antimicrobial effect in soap, or cause irritation of skin, but no published studies show which surfactants are best for removing microbes. We used pig skin as a model for human skin and a lathering device to simulate a hand wash. A 10% sodium lauryl sulphate mixture was the only treatment significantly different from a water wash. There was a strong correlation between increasing surfactant concentrations above the critical micelle concentration and mean microbial reduction.

Synthesis and properties of polyester-based polymeric surfactants from diterpenic rosin

A series of polymeric surfactants, poly acrylic acid rosin polyethylene glycol esters (P-AAR-PEG), have been synthesized from natural diterpenic rosin. Their structures were characterized by Fourier Transform Infrared Spectrometer (FTIR) and their molecular weights were characterized by Gel Permeation Chromatography (GPC). Their critical micelle concentration (CMC), surface tension (γCMC), foaming property (FP), and hydrophile-lipophile balance (HLB) value were evaluated. Their thermal properties were measured by Thermal Gravimetric Analyzer (TGA) and fluid behaviors were studied by Rotational Rheometer. The influence of concentration on the properties of oil-in-water emulsions was examined and contrasted the stability of emulsion by the mean droplet size between day1 and day7. The weight-average molecular weight of P-AAR-PEG ranged from 1770 to 5071. CMC values of P-AAR-PEG were ranged from 0.33 to 0.87g/L and the corresponding γCMC values were ranged from 37.8 to 39.1mN/m respectively. Their CMC and γCMC values decreased and then increased with the increment of molecular weight of hydrophile group. Rheological measurements indicated that the P-AAR-PEG solutions changed from pseudoplastic property to Newtonian with increasing shear rate. P-AAR-PEG1000 had good emulsion ability to turpentine in water. When the concentration of P-AAR-PEG1000 was 8wt%, the emulsion remained stable for more than 7days.

Essential oil from Pterodon emarginatus as a promising natural raw material for larvicidal nanoemulsions against a tropical disease vector

The oleoresin obtained from fruits of Pterodon emarginatus was previously subjected to development of larvicidal nanoemulsions. To our knowledge, no efforts aiming at developing nanoemulsions with the essential oil from this species were carried out. This study describes the preparation and evaluation of the larvicidal activity of a novel oil in water nanoemulsion prepared with essential oil from fruits of P. emarginatus against Aedes aegypti larvae. β-caryophyllene is the major compound, corresponding to 25.8% of relative percentage of the essential oil. A series of nanoemulsions were obtained and better physical results were achieved using polysorbate 80, suggesting that a required Hydrophile-Lipophile balance value of this oil is around 15. Mean droplet size decreased from 128.0 ± 6.2nm to 53.2 ± 0.5nm, when surfactant to oil ratio increased from 1.0 to 2.0. The nanoemulsion prepared with P. emarginatus essential oil and polysorbate 80 (1:1) was able to induce mortality on early 4th instar larvae. This study allowed preparation of nanoemulsions with essential oil from fruits of P. emarginatus for the first time, which proved to be a potential larvicidal against Aedes aegypti. The utilization of a low cost and solvent-free method can be considered an advantage in terms of potential applications of this natural product in ecofriendly integrative practices of vector control. Moreover, the great potential of this plant species is highlighted by the fact that its fruits can be obtained by a sustainable management of biodiversity, using the concept of standing trees to protect and stimulate conservation of the species.

Formulation, Characterization and Properties of Hemp Seed Oil and Its Emulsions.

The formulation, characterization, and anticipated antibacterial properties of hemp seed oil and its emulsions were investigated. The oil obtained from the seeds of Cannabis sativa L. in refined and unrefined form was characterized using iodine, saponification, acid values, and gas chromatography, and was employed for the preparation of stable oil-in-water emulsions. The emulsions were prepared using pairs of non-ionic surfactants (Tween, Span). The effects of the emulsification method (spontaneous emulsification vs. high-intensity stirring), hydrophilic lipophilic balance (HLB), type and concentration of surfactant, and oil type on the size and distribution of the emulsion particles were investigated. It was found that the ability to form stable emulsions with small, initial particle sizes is primarily dependent on the given method of preparation and the HLB value. The most efficient method of emulsification that afforded the best emulsions with the smallest particles (151 ± 1 nm) comprised the high-energy method, and emulsions stable over the long-term were observed at HBL 9 with 10 wt % concentration of surfactants. Under high-intensity emulsification, refined and unrefined oils performed similarly. The oils as well as their emulsions were tested against the growth of selected bacteria using the disk diffusion and broth microdilution methods. The antibacterial effect of hemp seed oil was documented against Micrococcus luteus and Staphylococcus aureus subsp. aureus. The formulated emulsions did not exhibit the antibacterial activity that had been anticipated.

Emulsifying properties and degradation characteristics of bioresorbable polymeric emulsifiers in aqueous solution and oil-in-water emulsion

Three amphiphilic bioresorbable copolymers derived from lactide (LA), ε-caprolatcone (CL) and poly(ethylene glycol) (PEG) were investigated for their emulsifying properties and degradation characteristics. Polymers consisted of 80 wt% hydrophilic PEG block and 20 wt% lipophilic PLA, PCL, PLACL block were synthesized by ring-opening polymerization of LA and/or CL in the presence of monomethoxy PEG. By possessing similar hydrophilic-lipophilic balance (HLB) values, these polymeric emulsifiers have an equivalent ability to stabilize squalane/water interfaces during emulsification. Degradation of polymers in aqueous solution and within emulsion was carried out in water at 37 °C selected to mimic the human body conditions. Our results demonstrated that the degradability intrinsic to each polymer is the predominant cause of destroying the emulsion. Moreover, polymer matrices within the emulsion exhibited lower degradation rates than the corresponding polymers in aqueous solution. These features are of great interest in pharmaceutical applications, especially for the design of sustained delivery systems.

Determination of Surface-Active Characteristics of a Natural Surfactant Extracted from Sapindus Saponaria

Abstract The pulp of the fruit of Sapindus saponaria (soapnut tree) consists mainly of saponin. Surface-active characteristics of this raw saponin such as critical micelle concentration, area per molecule and, hydrophilic-lipophilic balance were investigated; this information is valuable to assess its implementation in different applications of industrial interest. By using surface tension measures and dynamic light scattering studies, the value of critical micelle concentration was found in the range of 0.03 – 0.046 g mL−1. Further increase in the concentration of crude saponin leads to a constant value of surface tension (44 mN m−1). These results were analyzed using the Gibbs adsorption isotherm yielding an estimated value of the area occupied per molecule at the air/water interface of 57.2 A2. Besides, Griffin method was used to determine the hydrophilic-lipophilic balance value (14.3). Sapindus saponaria extract properties are comparable to that of commercial surfactants, hence it could be used as an...

Size and Stability of Curcumin Niosomes from Combinations of Tween 80 and Span 80

The ratios of Tween 80 to Span 80 are important in controlling the physicochemical characteristics of curcumin niosomes. Thus, in this study the correlations of combination of Tween 80 and Span 80 at different ratios with the size and stability of curcumin niosomes were investigated. Initially curcumin was dissolved in chloroform and methanol (v/v= 3:1), followed by the preparation of niosomes by thin-film hydration method with the mole ratio of mixture of Tween 80 and Span 80 to cholesterol of 2:1. The ratios of Tween 80 to Span 80 in the mixture were set at 1:1, 1:9, 9:1, 2:3 and 3:2 with Hydrophilic-Lipophilic Balance (HLB) values of 9.65, 5.37, 13.93, 8.58 and 10.72, respectively. As expected, niosome barely formed at HLB value 13.93. This might be due to the molecule being hydrophilic and well hydrated which inhibits the formation of a stable bilayer in solution. It was found that the formulation which has higher Span 80 and lower HLB value leads to larger niosome before sonication. The largest niosome size achieved from Tween 80 to Span 80 ratio of 1:9 and 2:3 was 77.36 and 59.85 μm, respectively. On the other hand, for the ratio of 3:2, the largest niosome formed before sonication was less than 50.00 μm. After sonication, the niosome size reduced to less than 35.00 μm for all formulations. It was showed that formulation with Tween 80 to Span 80 ratio of 1:9 has superior curcumin entrapment efficiency and best stability during storage. The results demonstrated that appropriate ratio of Tween 80 to Span 80 was necessary for forming small and stable curcumin niosomes.

Surfactant effects on water recovery from produced water via direct-contact membrane distillation

Increasing demand for oil and gas leads to the generation of substantial amount of produced water, bringing about deleterious impacts on the environment. Direct-contact membrane distillation (DCMD) could be a possible option for dewatering oil-in-water (O/W) emulsions because of many benefits brought by the DCMD process. However, these low surface tension solutions pose some difficult issues such as membrane fouling and pore wetting. The mechanisms involved are not fully understood due to the lack of study of the interaction between the emulsions and the membrane surface in the DCMD domain. To address the challenges, this study aims at developing a fundamental understanding of the relationship between surfactant-stabilized O/W emulsions and polyvinylidene fluoride (PVDF) membrane surface in DCMD operations. Effects of surfactant types (Span 20, Tween 20, and sodium dodecyl sulfate), oil concentration, and oil types (petroleum and vacuum pump oil) were systematically studied to better understand the fouling and wetting mechanisms involved. The results reveal that surfactant concentration and hydrophobicity had an influence on the membrane fouling and wetting behaviors. Surfactants with a lower hydrophilic-lipophilic balance (HLB) value could make the PVDF membrane surface less hydrophobic and cause less severe fouling by restraining the adsorption of oil droplets on the membrane surface. These findings suggest that membrane surface modification is required to achieve anti-fouling and anti-wetting properties to make DCMD an energy-efficient and effective technology for treating produced water.

Influence of the nonionic surfactants’ nature on the structures and properties of organo-montmorillonites

Montmorillonite (Mt) was modified with three nonionic surfactants, i.e., Span-80, Span-20 and OP-10. The influence of the structures and properties of nonionic surfactants on the structures and properties of organo-montmorillonite (OMt) was researched. X-ray diffraction results demonstrated that nonionic surfactants with low Hydrophile-Lipophile Balance (HLB) values could not intercalate into the interlayer space of Mt while surfactants with high HLB values could. Scanning electron microscope images indicated that the modified Mt was disaggregated into thin lamellas, instead of big particles. Surfactants were able to help to disperse Mt in water. Contact angle tests showed that the hydrophobicity of OMt was higher than raw Mt. However, the hydrophobicity of OMt was not as high as expected. The highest contact angle of OMt was 52°. With the increase of HLB values of nonionic surfactants, the hydrophobicity of OMt gradually decreased. The swelling ability of OMt in organic solvents was poor. The swelling ability of OMt was related to the structure of OMt and the HLB values of nonionic surfactants. Finally, the different mechanisms of OMt prepared with different nonionic surfactants were discussed.

Technological Evaluation of Emulsions Containing The Volatile Oil from Leaves of Plectranthus Amboinicus Lour.

Background:Plectranthus amboinicus Lour is a species which is widespread throughout tropical countries where it is widely used against respiratory tract disorders such as bronchodilator, antitussive, and expectorant conditions.Objective:This study aims to characterize the essential oil of P. amboinicus (PaEO) and produce and evaluate emulsions containing PaEO.Materials and Methods:The essential oil was characterized by physical-chemical analyses for density, refractive index, 90% ethanol solubility, color, appearance, and identification by gas chromatography coupled to mass spectrometry detection. The emulsions were prepared following a hydrophile-lipophile balance [HLB] spreadsheet design from two nonionic surfactants (Span 80® and Tween 20®) producing HLB values ranging from 4.3 to 16.7. The products were stored at room temperature at 5°C. The emulsion stabilities were tested both in the long and short-term.Results:The PaEO was obtained by steam distillation and the total extraction was reached after 3 hours yielding of 0.2% (w/w). This essential oil was characterized by physicochemical analyses for density [1.5 g.ml-1], refraction index [0.9167], ethanol 90% solubility [1:2], color, and appearance (yellow/clear). Nineteen components were identified in the oil, among them the sesquiterpenes: carvacrol [33.50%], p-cymene [28.20%] and γ-terpinene [14.77%]. The emulsions obtained successfully showed, for the first time, HLB values for essential oils from Plectranthus amboinicus [15.7].Conclusion:The experimental data shows a relationship between HLB values of the surfactant mixtures contributing to the emulsified systems production containing phytopharmaceuticals. Such an approach is of great importance to the development of lipid carriers for therapeutic drugs.SUMMARY The essential oil from leaves of Plectranthus amboinicus was extracted by steam distillation and characterized.The emulsions containing essential oil were produced and the stability was performed in the short and long term.The critical hydrophilic-lipophilic balance (HLB) of the essential oil was 15.7 and was achieved by the combination of surfactants (Tween 80® and Span 20®). Abbreviations used: PaEO: essential oil of P. amboinicus, HLB: hydrophilic-lipophilic balance, CI: Creaming Index, MET: micro-emultocrit technique

Prescription Optimization and Oral Bioavailability Study of Salvianolic Acid Extracts W/O/W Multiple Emulsion.

The purpose of this study is to develop a new method of preparing salvianolic acid extracts (SAE) water-in-oil-in-water (W/O/W) multiple emulsion (ME). SAE injection is used in the treatment of brain infarct and promotion of blood circulation in China. However, the injection is not convenient, and the oral preparation has poor bioavailability. Hence, a new preparation that is convenient and stable with good biological availability is required. SAE ME was prepared by two-step emulsification method. Combined with single-factor investigation and orthogonal test, the embedding rate and centrifugal retention rate were taken as the comprehensive indexes to optimize the formulation of SAE ME. The ME size was tested by laser particle size analyzer. The pharmacokinetic studies were conducted in Sprague-Dawley rats with HPLC-MS/MS method. The blood coagulation and hemorheology tests were conducted to assess the effect of preparation in rats. The best preparation technique for SAE ME is by the use of trospium chloride; SAE represent 12% of water in the phase, lipophilic emulsifier hydrophilic lipophilic balance value=4.3, lipophilic emulsifier is 20% of the oil phase. The median diameter of particle is (0.608±0.05) µm and the Cmax of ME is 3-fold higher compared to Cmax of free drug. The oral biavailability of ME is 26.71-fold higher than that of free drug with good effect on blood circulation. SAE ME is stable hence, improves the biological availability and slows down drug release.

Evaluation of Sucrose Fatty Acid Esters as Lubricants in Tablet Manufacturing.

Lubricants are essential additives in tablet formulations. Magnesium stearate (Mg-St) is the most commonly used lubricant in tableting. Here, we used sucrose fatty acid ester (SE) as an additive to manufacture tablets by direct compression. We evaluated the effects of hydrophile-lipophile balance (HLB) and the amount of SE on the flowability of a pharmaceutical powder using angle of repose and practical angle of internal friction measurements. In addition, we investigated the effects of SE on tablet properties. When SEs with an HLB ≥3 were added, the angle of repose was approximately the same as that of a pharmaceutical powder containing Mg-St, with no major differences in flowability. However, the practical angle of internal friction became closer to pharmaceutical powder containing Mg-St as HLB decreased. As HLB increased, the practical angle of internal friction approached the value of additive-free pharmaceutical powder. Tablets containing 2.0% Mg-St had a mean hardness of 40 N and disintegrated in approximately 6 min, whereas tablets containing 2.0% SE (low HLB) had a mean hardness of approximately ≥80 N and disintegrated within 3 min. The results indicate that SEs can be used as lubricants in tablet production by direct compression and to reduce problems associated with the use of Mg-St. In particular, we suggest that SEs with low HLB values can be used as excipients to achieve high tablet hardness and short disintegration time.

Properties of water in oil emulsions (W/O) stabilized with mixtures of PGPR and polyglycerol fatty acid esters

Water in oil (W/O) emulsions are dispersed systems which have very wide application as a carriers in the food, pharmaceutical and cosmetic industry products. The main problem with practical application of such systems is their low stability. The emulsifiers used to stabilize this type of emulsions are with low hydrophilic-lipophilic balance values. The present work examines the possibility of the application of mixtures of lipophilic emulsifiers polyglycerol polyricinoleate (PGPR) and polyglycerol fatty acid esters for stabilization of W/O emulsions. First of all, the adsorption properties of the used emulsifiers were examined by tensiometic measurements. Based on these results, two emulsifiers PGPR and decaglycerol decaoleate (Caprol 10G10O) were selected for the preparation of the emulsions, as well as their mass ratios and total concentrations. The results of the investigation of the emulsions properties (dispersion analysis and sedimentation stability) showed that more stable emulsions can be obtained by decreasing the Caprol 10G10O mass ratio and increasing the total concentration of emulsifiers.

Rheological properties of organo-palygorskite in oil-based drilling fluids aged at different temperatures

Aiming to develop a new excellent rheological additive for use in oil-based drilling fluids, palygorskite (Pal) was organically modified with three cationic surfactants using wet method. The surfactants were octadecyl trimethyl ammonium chloride (C18-A), benzyl dimethyl octadecyl ammonium chloride (C18-B) and dimethyl dioctadecyl ammonium chloride (DC18). The structure and properties of organo-palygorskite (OPal) and its use in oil-based drilling fluids were characterized by X-ray diffraction (XRD), scanning electronic microscope (SEM), thermal analysis, gel volume and rheological tests. Surfactant-modification did not change the crystal structure of Pal, but changed the aggregation of Pal fibers. Surfactants mainly coated on the surface of Pal. But the details were influenced by the molecular scale of surfactants and the coating level. The scale of polar heads of surfactants being smaller than the channels' scale is expected. Surface modification decreased the particle size of Pal and loosened the arrangement of Pal fibers. The thermal stability of OPal decreased as follows: C18-A-Pal>C18-B-Pal>DC18-Pal, as well as the thermal stability of corresponding oil-based drilling fluids. Particularly, C18-A-Pal fluids could bear heat of 200°C. OPal could increase the viscosity of oil-based drilling fluids well. In addition, the oil-based drilling fluids containing OPal showed excellent thixotropy aged above 150°C. Temperatures below 150°C increased the rheological properties of oil-based drilling fluids while high temperature helped to disperse the OPal particles and fibers. The rheological properties of oil-based drilling fluids containing OPal were influenced by surfactants nature (polar head scale of surfactant cation, Hydrophilic-Lipophilic Balance (HLB) value, molecular conformation), coating level and temperature. The rheological properties of OPal fluids indicated that OPal was very suitable for oil-based drilling fluids.

Ultrasonic assisted formation and stability of mustard oil in water nanoemulsion: Effect of process parameters and their optimization

The present work reports the ultrasound assisted preparation of mustard oil in water nanoemulsion stabilized by Span 80 and Tween 80 at different operating conditions. Effects of various operating parameters such as HLB (Hydrophilic Lipophilic Balance) value, surfactant volume fraction (φS), oil volume fraction (φO) and power amplitude were investigated and optimized on the basis of droplet size and stability of nanoemulsions. It was observed that minimum droplet size of about 87.38nm was obtained within 30min of ultrasonication at an optimum HLB value of 10, φS of 0.08 (8%, v/v), φO of 0.1 (10%, v/v) and ultrasonic power amplitude of 40%. The stability of the nanoemulsion was measured through visual observation and it was found that the unstable emulsions got separated within 24h whereas, stable emulsions never showed any separation until 90days. In addition to that, the kinetic stability of the prepared nanoemulsions was also assessed under centrifuge and thermal stress conditions. The emulsion stability was found to be unaffected by these forces as the droplet size remained unchanged. The ultrasound prepared emulsion was found to be long term stable even after 3months of storage at ambient conditions without any visual evidence of creaming and phase separation and also remained kinetically stable. FTIR analysis of the emulsions at different sonication conditions was carried out to examine the possible impact of ultrasonically induced chemical effects on oil structure during emulsification and it was found that the oil molecular structure was unaffected by ultrasonication process. The present work illustrates the formation and stability of mustard oil in water nanoemulsion using ultrasound cavitation which may be useful in food and cosmetic based applications.

Influence of the surfactants' nature on the structure and rheology of organo-montmorillonite in oil-based drilling fluids

Aiming to select appropriate organo-montmorillonites (OMt) for the use in oil-based drilling fluids, the influences of surfactants' nature on the structure of OMt, structure and rheology of OMt in oil-based drilling fluids were studied in this work. X-ray diffraction (XRD) results indicated a tendency that bigger modifiers resulted in higher basal spacing and more ordered internal arrangement. Scanning electron microscope (SEM) images testified a trend that modifiers with bigger size and low Hydrophile-Lipophile Balance (HLB) value resulted in more OMt lamellaes (thickness of ca. 50nm) scattered. Contact angle tests demonstrated that lipophilicity of OMt was influenced by the HLB values of surfactants. XRD results of OMt in oil-based drilling fluids indicated a tendency that surfactants with bigger size and low HLB values led to easier exfoliation in oil. OMt modified with small size and high HLB values obviously shrank while OMt modified with bigger size and low HLB values kept exfoliation above 180°C. The rheological flow model of OMt in oil-based drilling fluids was very different from the surfactants' size and polarity. Exfoliation of OMt in oil improved the rheological properties of oil-based drilling fluids, such as viscosity and thixotropy. Thixotropy of oil-based drilling fluids benefited from the exfoliation of OMt in oil while excessive exfoliation was harmful to increasing viscosity.

Production and Emulsifying Effect of Polyglycerol and Fatty Acid Esters with Varying Degrees of Esterification

AbstractEsters with acyl groups can be formed by the esterification of polyglycerol. The purpose of the present study was to produce fatty acid esters [hexanoic (caproic), octanoic (caprylic), decanoic (capric), dodecanoic (lauric), tetradecanoic (myristic), hexadecanoic (palmitic), octadecanoic (stearic)] and polyglycerol (average number‐of degrees of polymerization of 5) with varying degrees of esterification and to examine their emulsifying properties. A number of fundamental catalysts of polyglycerol acylation reactions by methyl esters of carboxylic acid were studied, and sodium methoxide was found to be the best choice. The temperature rate of transesterification increased from 180 to 220 °C with the fatty acid chain alkyl residue. Synthesized mono‐, di‐, tri‐, tetra‐, and heptaesters of various fatty acids and polyglycerol provided the highest hydroxyl values from 15 to 815 mg KOH g−1 and saponification values from 82 to 321 mg KOH g−1. The emulsifying properties were assessed for all polyglycerol and fatty acid esters, with results showing maximum emulsifying effect for tri‐ and tetraesters of capric, lauric, and caprylic acids. Regardless of the hydrophilic–lipophilic balance value (HLB) of polyglycerol esters and carboxylic acid, a 4:1 ratio of sunflower oil to water formed a water‐in‐oil type emulsion. When mixing oil and water in a 1:1 ratio, mono‐ and diesters of polyglycerol formed an oil‐in‐water type emulsion, heptaesters formed a water‐in‐oil type emulsion, and tri‐ and tetraesters formed both of types of emulsions, depending on the length of the acid hydrocarbon radicals.

사삼산화철 기반의 소립자시약(Small Particle Reagent)의 접착면 잠재지문 현출 효과에 영향을 미치는 요인

강력범죄사건에서 발견할 수 있는 증거물인 테이프는 접착면에 지문이 쉽게 유류될 수 있다. 청 테이프에 유류된 지문을 현출하고자 사삼산화철(<TEX>$Fe_3O_4$</TEX>)기반의 Small Particle Reagents(SPR)를 사용하여 SPR의 제조비율 및 현출에 영향을 주는 요인에 대해 연구하였다. SPR이 지문현출에 영향을 주는 요인은 제조시 첨가되는 분말의 양, 계면활성제의 양, 계면활성제의 HLB(hydrophile-lipophile balance)에 의해 영향을 받는다. 증류수 100ml를 기준으로 분말의 양은 0.5g~1.0g일 때 융선에 적절한 양이 흡착되었으며 계면활성제의 양은 0.5ml이상이면 배경에 흡착된 분말들을 잘 씻어냈다. 또한 계면활성제의 HLB가 배경과 융선과의 대조비를 높이는 중요한 요인이었으며 유류된 지문의 지질 성분을 용해시키지 않는 11~18사이의 HLB가 뛰어난 현출력을 보였다. Latent fingerprint left on the adhesive sides of tapes can be easily found at a crime scene. Small Particle Reagents(SPR) based on iron oxide(<TEX>$Fe_3O_4$</TEX>) is a technique for the detection of a latent fingerprint adhesive surface. In this study, found out that the causes affecting the quality of the fingerprints developed when used SPR based on iron oxide. To a suspension of 0.5g of iron oxide in 100ml of distilled water, 0.5ml or more surfactant were added can be developed latent fingerprints of good quality. In addition, using surfactants HLB(hydrophile-lipophile balance) value of 11~18 showed good contrast to the background and latent fingerprint.