Abstract: The inhibiting effect of 1,3,5-triphenylformazane(TFH) on the free radical polymeriza-tion of methyl methacrylate(MMA), initiated by AIBN, has been studied by dilatometricmethod.The results indicated that when TFH was incorporated with another inhibitors suchas benzoquinone(BQ) or 1,4-naphtholquinone(NQ), the induction period of polymerizationof MMA become longer than when TFH, hydroquinone(HQ) and p-tert-butylcatechol(TBC)was used alone. The results pointed out that when the mixture of TFH and chloranil(CA)in whatever proportion used, the induction period was shorter than when TFH used alone.Prec radicals TF· have been observed in the polymerization of MMA with added TFH.

Key words: Inhibitor, Polymerization, 1,3,5-Triphenylformazane, Quinones, Methyl methacrylate