Reaction to fire of recycled poly(ethylene terephthalate)/polycarbonate blends

In the present paper, we study the effect of both morphology and compatibilization on the reaction to fire of blends of recycled poly(ethylene terephthalate) (PETr) with recycled polycarbonate (PCr). It is shown that while the flame retardancy of blends containing less than 50% w/w of PCr increases almost linearly with PCr content, blends containing more than 50% w/w of PCr react to fire like pure PCr. This change of reaction to fire correlates with the formation of a continuous PCr phase in the blend.The compatibilization of the blend by a trans-esterification reaction leading to the formation of copolymers at the interface decreases the overall fire performances due to PETr chain breaking as a side effect which results in a strong decrease of blend viscosity and of the temperature at which mass loss begins.