Abstract
The effect of perfluoroalkane sulfonic acid on the flame retardancy of polycarbonate (PC) has been studied. In particular, the very small amount of additives to restrain the combustion, as well as the thermal degradation path, was focused on. The flaming combustion times of PC blended with 100 ppm of the strong acid salts by the Underwriter Laboratory (UL)‐test were less than 5 sec, which satisfied the V‐0 level of the UL‐94 test. The ignition times of the UL test did not change remarkably, but those observed in a cone calorimeter test clearly got shorter. Referring to the results of thermal and elemental analyses, the process by which PC was shown excellent flame retardancy is not dehydration and subsequent char‐formation, but includes different scission routes. In particular, the flame retardancy strongly depends on the scission of the isopropylidene group on the main chain.
Acknowledgment
We greatly appreciate New Energy and Industrial Technology Development Organization (NEDO) for her proposal of research fund to this study for three years since 1999.