1 Scope
This International Standard specifies a method of determining the total active-oxygen
content of organic peresters.
It applies to those peresters used to initiate crosslinking of unsaturated-polyester thermosets.
The peresters most widely used in the crosslinking of unsaturated-polyester resins are given in
Table 1.
Table 1
—
Main types of organic perester
|
Perester
|
Molecular mass |
|
tert-Butyl perbenzoate |
194,2 |
|
tert-Butyl 2-ethylperhexanoate |
216,3 |
|
iso-Propyl tert-butylperoxy carbonate |
176,2 |
|
tert-Amyl 2-ethylperhexanoate |
230,3 |
|
tert-Amyl perbenzoate |
208,3 |
|
tert-Butyl 3,5,5-trimethylperhexanoate |
230,4 |
Butyl peresters may contain traces of tert-butyl hydroperoxide (TBHP), the active oxygen in which can be determined separately
from that in the perester itself (see annex A). The active-oxygen content of the perester alone can then be obtained by subtraction.