The effects of the addition of 2.38×10-2 to 2.86×10-2 M AIBN and 8.8×10-2 to 6.1×10-4 M six substituted hydroxylamines

such as

N

N-diethlhydroxylamine (DEHA)

N

N'-diisopro-pylhydroxylamine (DIPHA)

N-hydroxyl-mofpholine ; (MPHA)

2

2

6

6-tetramethyl-4-hydro xyl-piperidinehydroxylamine (TMHPHA)

N-phenylhydroxylamine (PHA) and N

N'-diph-enylhydroxyamine (DPHA) at 60℃ on the bulk polymerization of vinyl acetate (VAC) and .acrylonitrile (AN) has been studied respectively. The results showed that all six hydroxyla-mines exhibited inhibiting properties. The effect is more pronounced for VAC than for AN. At the sametime the chain transfer constants (Cs) of these compounds in bulk polymerization of VAC and AN has been calculated respectively by Mayo equation. The result demonstrated that the Cs value for VAC in bulk polymerization is larger than that of AN under same condition. These differences not only depend on the structure of six hydroxylamines and the nitroxide ra-dical derved from them in reaction

but also on the electron-donating or electronaccepting pro-perties of monomers used and radicals formed.