Titration Application Note T-136
Determination of epoxide
equivalents in two-component
adhesive according to DIN EN
ISO 3001
The analysis of the epoxide equivalent is based on the reaction of hydrogen
bromide with the epoxide groups of the sample. Hydrogen bromide is produced
by the reaction of tetraethylammonium bromide (TEABr) with standardized
perchloric acid.
Method description
Sample
Parameters
Two-component adhesive
Titration Mode
DET U
Stirring rate
8
Sample preparation
Pause
30 s
The sample should only be taken from the epoxidecontaining component.
Signal drift
30 mV/min
Min. waiting time
5s
Max. waiting time
32 s
Meas. point density
4
EP criterion
10
EP recognition
Greatest
Configuration
907 Titrando
2.907.0010
800 Dosino
2.800.0010
804 Ti Stand with stand
2.804.0040
802 Stirrer
2.802.0020
20 mL Dosing unit
6.3032.220
Solvotrode easyClean
6.0229.010
Solutions
Titrant
c(HClO4) = 0.1 mol/L in
anhydrous glacial acetic acid
If possible, this solution
should be bought from a
supplier.
TEABr solution
β(TEABr) = 250 g/L
25 g tetraethylammonium
bromide are weighed into a
100 mL volumetric flask,
dissolved in glacial acetic
acid and the flask is filled up
to the mark with glacial
acetic acid.
This solution is not very
stable and should be
prepared daily.
Chloroform
p.a.
Glacial acetic acid
p.a.
Analysis
Titration Application Note T-136
Version 1
The sample, containing 0.6 to 0.9 mmol epoxy groups,
is weighed into a titration beaker. The sample is then
dissolved in 10 mL chloroform. Afterwards, 10 mL
β(TEABr) = 250 g/L and 20 mL glacial acetic acid are
added and the solution is titrated with c(HClO4) =
0.1 mol/L until after the equivalence point.
Results
Mean result for n = 3
Epoxide equivalent / (g/mol)
186.35
s(rel) / %
0.98