乙烯系单体自由基聚合的阻聚效应研究 Ⅺ.羟胺类化合物对醋酸乙烯酯和丙烯腈自由基聚合的影响及链转移常数的测定

<正> 前文报道六种取代羟胺对苯乙烯自由基聚合阻聚反应活性及机理。本文继续研究二乙基羟胺(DEHA)、二异丙基羟胺(DIPHA)、吗啉羟胺(MPHA)、2,2,6,6-四甲基-4-羟基哌啶羟胺(TMHPHA)、苯基羟胺(PHA)和二苯基羟胺(DPHA)对富电

INHIBITING EFFECT OF RADICAL POLYMERIZATION FOR VINYL MONOMERS XI.Studies on the Inhibition and Their Chain Transfer Constants of Substituted Hydroxylamine Compounds in Bulk Polymerization of Vinyl Acetate and Acrylonitrile

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 hydroxylamines exhibited inhibiting properties. The effect is more pronounced for VAC than for AN. At die same time the chain transfer constants (Ct) of these compounds in bulk polymerization of VAC and AN has been calculated respectively by Mayo equation. The result demonstrated that the G 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 radical derved from them in reaction, but also on the electron-donating or electronaccepting properties of monomers used and radicals formed.