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.