HLB calculation

HLB calculated from glc relative retention ratios except tor PLURONIC R series estimated ranges Not compielety soluble tns Insoluble... 

One of the most important characteristics of the emulsifier is its CMC, which is defined as the critical concentration value below which no micelle formation occurs. The critical micelle concentration of an emulsifier is determined by the structure and the number of hydrophilic and hydrophobic groups included in the emulsifier molecule. The hydrophile-lipophile balance (HLB) number is a good criterion for the selection of proper emulsifier. The HLB scale was developed by W. C. Griffin [46,47]. Based on his approach, the HLB number of an emulsifier can be calculated by dividing... 

The HLB of a relatively pure poly(oxyethylene) adduct can be calculated from theoretical data [37]. For these agents the HLB is an indication of percentage by mass of the hydrophilic portion, divided by five to give a conveniently small number. For example, if the hydrophilic portion of a purely hypothetical nonionic agent accounted for 100% of the molecule (such a product cannot, of course, exist), its HLB is 20. Similarly, a more plausible product in which 85% of the molecule is accounted for by the hydrophilic portion has an HLB of 85/5 = 17. The ICI Americas Inc. method of calculating the theoretical HLB of a sorbitan monolaurate nonionic having 20 oxyethylene units per molecule is given in... 

As explained earlier, however, the actual constitution of a surfactant rarely conforms to its nominal structure. Consequently the theoretical method of calculation is of limited utility, practical methods being more reliable. The HLB value may be determined directly by analysis or by comparison with a range of surfactants of known HLB values. An analytical method for the sorbitan monolaurate described above uses Equation 9.2 [37]. 

Once the HLB values of a range of surfactants are known it is an easy matter to calculate the HLB value of a mixture as follows ... 

The i value and HLB value of polyhydroxyl and polycarboxylic xanfhates are calculated and shown in Table 5.5. It is obvious that the polyhydroxyl xanthate with more hydroxyl groups and polycarboxylic xanthate with more carboxylic groups have greater i or HLB value. Taking the i or HLB values as x-axis and the flotation recovery of arsenopyrite or pyrrhotite at depressant concentration... 

Surfactant Properties. Hydrophyllic-lipophyllic balance (HLB) was calculated from equation 2 (3) Molecular weights and chemical compositions were obtained from the literature or from the manufacturers. The partition coefficients and HLB values were not... 

Water-Hexadecane Partition Coefficients of NPE s and Calculated Values of HLB ... 

Original concentration = 0.2 g/1 Average mole ratio of ethylene oxide Average of four samples, unless specified otherwise Average of two samples Calculated from HLB = 0.36 In Kp + 7... 

Different surfactants are usually characterised by the solubility behaviour of their hydrophilic and hydrophobic molecule fraction in polar solvents, expressed by the HLB-value (hydrophilic-lipophilic-balance) of the surfactant. The HLB-value of a specific surfactant is often listed by the producer or can be easily calculated from listed increments [67]. If the water in a microemulsion contains electrolytes, the solubility of the surfactant in the water changes. It can be increased or decreased, depending on the kind of electrolyte [68,69]. The effect of electrolytes is explained by the HSAB principle (hard-soft-acid-base). For example, salts of hard acids and hard bases reduce the solubility of the surfactant in water. The solubility is increased by salts of soft acids and hard bases or by salts of hard acids and soft bases. Correspondingly, the solubility of the surfactant in water is increased by sodium alkyl sulfonates and decreased by sodium chloride or sodium sulfate. In the meantime, the physical interactions of the surfactant molecules and other components in microemulsions is well understood and the HSAB-principle was verified. The salts in water mainly influence the curvature of the surfactant film in a microemulsion. The curvature of the surfactant film can be expressed, analogous to the HLB-value, by the packing parameter Sp. The packing parameter is the ratio between the hydrophilic and lipophilic surfactant molecule part [70] ... 

Variations in the relative polarity or nonpolarity of surfactants (hydrophilic or hydrophobic) signiLcantly inLuence its interfacial behavior. A measure of this parameter is useful to classify surfactants. An HLB number is a direct expression of the hydrophilic and hydrophobic character of surfactants and is a useful means for surfactant classiLcation. HLB numbers for surfactants may be either calculated using the following empirical equation ... 

The amphiphilic nature of many emulsifying agents (particularly non-ionic surfactants) can be expressed in terms of an empirical scale of so-called HLB (hydrophile-lipophile balance) numbers222 (see Table 10.1). The least hydrophilic surfactants are assigned the lowest HLB values. Several formulae have been established for calculating HLB numbers from composition data and they can also be determined experimentally - e.g. from cloud-point measurements123,125. For mixed emulsifiers, approximate algebraic additivity holds. 

There also exist empirical equations for calculating HLB values. For example, in the case of polyoxyethylene alcohols CnH2n+i(OCH2CH2)mOH, a class of non-ionic surfactants, the HLB can be calculated from ... 

Figure 8 shows temperature dependence of the wetting power of PAE, SAE and NPE each having about the same calculated HLB. 

Griffin developed a simple equation for calculation of the HLB number of certain numbers of nonionic surfactants such as fatty acid esters and alcohol ethoxylates. For the polyhydroxy fatty the HLB number is given by the equation... 

For the simpler alcohol ethoxylates, the HLB number can be calculated from the weight percentages of oxyethy-lene E and polyhydric alcohol P, i.e.,... 

In spite of these important differences, silicone surfactants share much in common with conventional surfactants. Equilibrium and dynamic surface tension vary with concentration and molecular architecture in similar ways. Silicone surfactants self-associate in solution to form micelles, vesicles and liquid crystal phases. Self-association follows similar patterns as molecular size and shape are varied and silicone surfactants containing polyoxyalkylene groups exhibit a cloud point. HLB values can be calculated for silicone surfactants, although more useful values can be obtained from calculations that take into account the differences between silicone and hydrocarbon species. 

There are several empirical expressions to calculate the HLB values based on the chemical structures present. If the hydrophilic region is polyoxyethylene, the HLB value is calculated by ... 

It is not easy to match the required HLB value of the oil or the oil mixture with that of a single surfactant to form the most stable emulsion. The appropriate combination of surfactants (usually a binary system) should be chosen. The HLB value of the binary mixture of surfactants A ( HLBA ) and B ( HLBb ) is calculated by ... 

First, the required HLB value of the oil phase mixture must be calculated. The total weight percent of the oil phase is 43%. The weight fractions of each oil in the oil phase are 24/43,14/43, and 5/43 for beeswax, mineral oil, and cetyl alcohol, respectively. The HLB value of the oil mixture is given by ... 

The data for surface tension and contact angle, as well as the calculated values of the film pressure, n, are given in Table I, and the dependence of the film pressure on HLB is shown in Figure 1. 

The shapes of the curves are roughly similar, but there is a distinct dependence on the nature of the substrate, particularly with respect to the position of the maximum. Figure 2 shows the herbicidal activity of 2,4-D (containing 1.0% surface-active agent) on com and soybean plants, from the data of Jansen (II). These data were not originally presented in terms of HLB, and the HLB-values have been calculated from the... 

The effect of the HLB of surfactant blends (calculated as the weight average) on the stability of the concentrated emulsions is presented in Fig. 11. (No w/o concentrated emulsion could be prepared using the surfactant blends employed in Fig. 11 because of the phase inversion that occurred at the beginning of the... 

Calculate the HLB number for oleic acid, sodimn oleate, and sodium lauryl sulfate. 

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