Measurement of HLB (Hydrophile - Lipophile Balance) values by NMR
HLB (Hydrophilic - Lipophilic Balance) is the ratio of oil and water-soluble constituents of a non ionic surfactant.
Griffin, who proposed the following calculation method, originally developed the system in 1954:
HLB = MH/M * 20 or %MH/5
...where MH is the molecular mass of the hydrophilic portion of the Molecule, and M is the molecular mass of the whole molecule giving a result on an arbitrary sclae of 0 to 20.
The lower the HLB the more lipophilic or oil soluble the surfactant becomes. The higher the HLB the more water soluble or hydrophilic the surfactant becomes. HLB values are traditionally calculated for nonionic surfactants for example Oleyl alcohol 20 mole ethoxylate would have a calculated HLB of 880/1150 * 20 - 15.3
Alternatively, HLB may be determined experimentally by invert emulsion experiments, gas-liquid chromatography or NMR.
HLB Numbers |
|
Ethylene Oxide % mole |
|
Applications |
4-6 |
|
20-30 |
|
W/O emulsifier |
7-15 |
|
35-75 |
|
Wetting agent |
8-18 |
|
40-90 |
|
W/O emulsifier |
10-15 |
|
50-75 |
|
Detergent |
10-18 |
|
50-90 |
|
Solubiliser |
Comparison of NMR experimental derived HLB against supplied HLB:
Non Ionic |
|
HLB NMR |
|
HLB Manufacturer |
|
Difference |
Tween 20 |
|
16.8 |
|
16.6 |
|
0.2 |
tween 21 |
|
11.8 |
|
13.3 |
|
-1.5 |
Tween 80 |
|
15.2 |
|
15.0 |
|
0.2 |
Tween 85 |
|
15.0 |
|
11.0 |
|
4.0 |
Tergitol 15s9 |
|
13.7 |
|
13.3 |
|
0.4 |
Lubrol 17A17 |
|
15.1 |
|
0.0 |
|
15.1 |
Brij C20PA |
|
16.0 |
|
15.7 |
|
0.3 |
Brij C20PA |
|
15.9 |
|
15.7 |
|
0.2 |
Lutensol NP 10 |
|
14.9 |
|
14.0 |
|
0.9 |
MYRJ 59 |
|
18.8 |
|
18.8 |
|
0.0 |
MYRJ 49P |
|
15.3 |
|
15.0 |
|
0.3 |
MYRJ S20 |
|
15.3 |
|
15.0 |
|
0.3 |
MYRJ 53P |
|
17.7 |
|
0.0 |
|
17.7 |
Arlatone 983 |
|
9.8 |
|
7.5 |
|
2.3 |
Arlatone 983 |
|
9.0 |
|
7.5 |
|
1.5 |
Atmer 154 |
|
14.6 |
|
14.5 |
|
0.1 |
Nonylphenol 10 |
|
14.9 |
|
13.3 |
|
1.6 |
Advantages:
NMR provides a quick and accurate method for determination of HLB values
Disadvantages:
This method works best with alcohol ethoxylates and fatty acid ethoxylate esters it becomes increasingly inaccurate with addition of PPG. Therefore would not recommend this method for PPG containing non ionic's. The system is yet untested on blends of non ionic ethoxylates consequently it needs validation with non ionic mixtures with known HLB values.
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